Nutrition Exam 2

Describe the different types, structures, and functions of lipids including fatty acids (7 matching, 2) 5.2 Lipids: Triglycerides, Phospholipids, and Sterols (pp. 162-167)

Fatty acids and triglycerides fatty acids: the simplest form of lipids essential fatty acids triglycerides phospholipids sterols

Explain why plant oils are hydrogenated and describe the health implications of trans-fats. (2) 5.1 Lipids: Triglycerides, Phospholipids, and Sterols (pp. 164) 5.3 Fats and Oils in Foods, Rancidity Limits Shelf Life of Foods, Hydrogenation of Fatty Acids in Food Production Increases Trans Fatty Acid Content (pp. 174-176)

General Lipid info: Lipids are composed primarily of the elements carbon and hydrogen; they contain fewer oxygen atoms than do carbohydrates. Chemical energy can be derived from breakdown of all those carbon-hydrogen bonds, so lipids yield more than twice as much energy (9 kcal per gram) as carbohydrates or proteins (4 kcal per gram). Lipid is a generic term that includes triglycerides, phospholipids, and sterols. As a class of nutrients, lipids share one main characteristic: they do not readily dissolve in water. Triglycerides are the most common type of lipid found in the body and in foods. ---Each triglyceride molecule consists of three fatty acids bonded to glycerol. ---Phospholipids and sterols (including cholesterol) are also classified as lipids, although their structures can be quite different from the structure of triglycerides. The foods highest in fat (and therefore energy density) include salad oils and spreads such as butter, margarine, and mayonnaise. ---All of these foods contain close to 100% of calories as fat While you certainly should monitor the total amount of fat, the type of fat in foods is another important consideration when it comes to selecting a dietary pattern that promotes optimal health. Fatty acid types: ---each dietary fat, or triglyceride, is a complex mixture of many different fatty acids, the combination of which provides each food its unique taste and smell. Fatty acids can be saturated or unsaturated with hydrogen. Chemically speaking, a carbon atom can form four bonds. Within the carbon chain of a fatty acid, each carbon bonds to two other carbons and to hydrogens. The carbons that make up the chain of a saturated fatty acid are all connected to each other by single bonds. This allows the maximum number of hydrogens to be bound. Just as a sponge can be saturated (full) with water, a saturated fatty acid, such as stearic acid, is saturated with hydrogen. The saturated fatty acids are very straight and linear and therefore can pack very close together. This close packing or stacking of saturated fat molecules makes them solidify at room temperature. ---If the carbon chain of a fatty acid contains a double bond, those carbons in the chain have fewer bonds to share with hydrogen, and the chain is said to be unsaturated. A fatty acid with only one double bond is monounsaturated. Canola oil, olive oil, and avocados contain a high percentage of monounsaturated fatty acids. If two or more of the bonds between the carbons are double bonds, the fatty acid is even less saturated with hydrogens, and so it is polyunsaturated. The double bonds in unsaturated fatty acids create kinks in their structure that keep them from packing closely together, so they are liquid at room temperature. Corn, soybean, sunflower, and safflower oils are rich in polyunsaturated fatty acids. ---Unsaturated fatty acids, with their double bonds, can exist in two different structural forms: the cis and trans forms. In nature, monounsaturated and polyunsaturated fatty acids usually are in the cis form. In a cis fatty acid, the hydrogens are on the same side of the carbon-carbon double bond. During certain types of food processing, some hydrogens are transferred to opposite sides of the carbon-carbon double bond, creating a trans fatty acid. The cis bond causes the fatty acid's carbon chain to bend, whereas the trans bond allows the chain to remain straighter. This makes it similar to the shape and functions of a saturated fatty acid. ------Some trans fatty acids, known as conjugated linoleic acid (CLA), occur naturally. CLA is a family of fatty acids derived from linoleic acid. The bacteria that live in the rumens of some animals (cows, sheep, and goats, for example) produce trans fatty acids from the polyunsaturated fats in the grass the animals are fed. These natural trans fats, or CLA, eventually appear in foods such as beef, milk, and butter. CLA contains both cis and trans bonds, and the trans bond is in a different location compared to industrial trans fats. Research studies suggest that CLA improves insulin levels in diabetics and decreases the risk of heart disease, cancer, and obesity—the very same diseases that industrial trans fats have been shown to increase. About 20% of trans fatty acids in our diets come from this source. Dietary supplements of CLA are available but are highly variable in their quality. Trans fats: Trans fatty acids tend to increase blood cholesterol more than saturated fat ---main food sources: Margarine (squeeze, tub, stick), shortening Health implications of trans fats: ---Decomposing oils emit a disagreeable odor and taste sour and stale (ex. Stale potato chips) ------The double bonds in unsaturated fatty acids break down, producing rancid by-products. Ultraviolet light, oxygen, and heat (as in deep-fat frying) can break double bonds and, in turn, destroy the structure of polyunsaturated fatty acids. ---Saturated fats and trans fats can more readily resist these effects because they contain fewer carbon-carbon double bonds. ---Rancidity is a problem for the food industry and restaurant business because it reduces a product's shelf life. ------To increase shelf life, manufacturers often add partially hydrogenated plant oils to products. Hydrogenation: ------If oils with unsaturated fatty acids are used to replace solid fats, they often must be made more saturated (with hydrogen), as this solidifies the vegetable oils into shortenings and margarines. ------Hydrogen is added by bubbling hydrogen gas under pressure into liquid vegetable oils in a process called hydrogenation ------The fatty acids are not fully hydrogenated to the saturated fatty acid form, as this would make the product too hard and brittle ------Partial hydrogenation—leaving some monounsaturated fatty acids—creates a semisolid product. Trans-fats from hydrogenation: ---The process of hydrogenation produces trans fatty acids ---Most natural monounsaturated and polyunsaturated fatty acids exist in the cis form, causing a bend in the carbon chain, whereas the straighter carbon forms of trans fat more closely resemble saturated fatty acids ---This may be the mechanism whereby trans fat increases the risk for heart disease. ------trans fats increase overall inflammation in the body, which is not healthful. ------Thus, the Dietary Guidelines for Americans, the American Heart Association, and the Food and Nutrition Board each recommend minimal trans fat intake, or avoid food sources of trans fats, such as foods prepared with partially hydrogenated oils ------In 2015, the FDA determined that partially hydrogenated oils—the main sources of trans fats in the diet—are no longer "generally recognized as safe" for use in human food products ---------Partially hydrogenated soybean oil—rich in trans fat—became the major fat in food processing when manufacturers eliminated the tropical oils rich in saturated fat (palm, palm olein, and coconut). While foods made with partially hydrogenated oil were becoming popular, there was very little known about the trans fats they contained and their harmful effects. Currently, trans fat intake in North America amounts to 3 to 4 grams per day Minimizing trans fat intake---general guidelines are: ---Limit consumption of: ------fried (especially deep-fat fried) food items ------any pastries or flaky bread products (such as pie crusts, crackers, croissants, and biscuits), and cookies ---Most importantly, use little or no stick margarine or shortening ------Instead, substitute vegetable oils and softer tub margarines (whose labels list vegetable oil or water as the first ingredient) ---Avoid deep-fat frying any food in shortening. ------Substitute baking, panfrying, broiling, steaming, grilling, or deep-fat frying in unhydrogenated oils with high "smoke points," meaning they do not break down at deep-frying temperatures (peanut, safflower, sunflower, and canola oils are good choices) ---Replace nondairy creamers with reduced-fat or fat-free milk, as most nondairy creamers are rich in partially hydrogenated vegetable oils ---Finally, read the ingredients on food labels ------If partially hydrogenated vegetable oil is one of the first three ingredients on the label, you can assume that there is a significant amount of trans fat in the product

Describe BMI and other ways to assess weight, body composition, and fat distribution, and identify their limitations. Calculate and interpret BMI & interpret waist measurements to assess chronic disease risks. (6, 3 matching) 7.3 Assessing Healthy Body Weight (pp. 245-250) and Figure 7-17

Listening to the body's hunger cues, regularly eating a balanced and healthy dietary pattern, and remaining physically active are all positive behaviors that help one maintain a healthy weight over time. Indications that your weight may be unhealthy include the following: ---Hypertension (high blood pressure) ---Elevated non-HDL cholesterol ---Family history of obesity or obesity-related diseases ---Pattern of upper-body (apple-shaped) android fat distribution ---Elevated blood glucose (hyperglycemia) Currently, body mass index (BMI) is the most widely used weight-for-height standard because it is a noninvasive clinical measurement related to risk of disease for most individuals Calculating BMI: (weight (pounds) × 703) / height squared (inches) Body Mass Index Categories: --Underweight: <18.5 --Healthy weight: 18.5-24.9 --overweight: 25-29.9 --obese: 30-39.9 --severely (morbidly) obese: 40 or greater Any weight-for-height standard remains a crude measure and does not consider body fatness ---a BMI of 25 to 29.9 is a marker of overweight (compared to a standard population) and not necessarily a marker of excessive body fatness. ---Many men (especially athletes) have a BMI greater than 25 because extra muscle mass weighs more. ---Also, very short adults (under 5 feet tall) may have a high BMI that may not necessarily reflect overweight or fatness. ---For this reason, BMI should be used only as a screening tool for overweight or obesity ---Adult BMIs should not be applied to children, growing adolescents, frail older adults, pregnant and lactating women, and highly muscular individuals Diagnosing Obesity: ---BMI values can be used as a convenient clinical tool to screen for overweight (BMI ≥ 25), obesity (BMI ≥ 30), and morbid obesity (BMI ≥ 40) in individuals older than 20 years of age ---Medical experts, however, recommend that an individual's diagnosis of obesity should not be based primarily on body weight or BMI but rather on the total amount of fat in the body, the location of body fat, and the presence or absence of weight-related medical conditions. Estimating body fat content: ---Good to acceptable amounts of body fat: ------about 11% to 20% for men ------and 16% to 30% for women ---Obese amount of body fat: ------men with over 25% body fat ------women with over 35% body fat To measure body fat content accurately, both body weight and body volume of the person are used to calculate body density. ---Body weight is easy to measure on a conventional scale. ---Of the typical methods used to estimate body volume, underwater (hydrostatic) weighing remains the most accurate. ------This technique determines body volume using the difference between conventional body weight and body weight measured while submerged under water, along with the relative densities of fat tissue and lean tissue, using a mathematical Page 247formula. This procedure requires that an individual be totally submerged in a tank of water, with a trained technician directing the procedure. ---(Bod Pod)® is another method of determining body volume. Body volume is quantified by measuring the space a person takes up inside a measurement chamber Body density = body weight / body volume % body fat = (495 ÷ body density) −450 Other ways of calculating body fat: ---Skinfold thickness measurements are also a common anthropometric method to estimate total body fat content, although there are some limits to its accuracy. ------Clinicians use calipers to measure the fat layer directly under the skin at multiple sites and then plug these values into a mathematical formula ---The analysis of bioelectrical impedance (BIA) is also used to estimate body fat content. ------This procedure sends a painless, low-energy electrical current through the body to estimate body fat. This estimation is based on the assumption that adipose (fat) tissue resists electrical flow more than lean tissue because it has a lower electrolyte and water content. More adipose tissue has proportionately greater electrical resistance than lean tissue. Within a few seconds, bioelectrical impedance analyzers convert body electrical resistance into an approximate estimate of total body fat, as long as hydration is adequate in the person being measured. Dehydration skews these results. Body composition monitors, better known as body fat calculators, which use bioelectric impedance, are now available for home use. These machines are similar in shape and use to bathroom scales, but their main purpose is to measure body fat. An electrical current passes easily through conductive foot pads and/or handheld electrodes. ---A more advanced determination of body fat content can be made using dual energy X-ray absorptiometry (DEXA). ------ DEXA is considered the most accurate way to determine body fat, but the equipment is expensive and not widely available. This x-ray system allows the clinician to separate body weight into separate components: fat, fat-free soft tissue, and bone mineral. Additional software can determine body fat distribution. The typical whole-body scan requires about 10 to 25 minutes, and the dose of radiation is less than a chest X ray. An assessment of bone mineral density and the risk of osteoporosis can also be made using DEXA Using body fat distribution to further evaluate obesity: ---In addition to the amount of fat we store, the location of that body fat is an important predictor of health risks. Some people store fat in upper-body areas, whereas others store fat lower on the body. Upper-body (android) obesity: ---Characterized by a large abdomen or waist, is more often called abdominal, visceral, or central obesity and is related to insulin resistance and fatty liver leading to obesity-related chronic diseases such as cancer, type 2 diabetes, high blood lipids, and heart disease. ---Because men typically develop upper-body obesity, it is also known as android obesity. ---While other adipose cells empty fat into general blood circulation, the fat released from abdominal adipose cells goes directly to the liver, by way of the portal vein. ---This influx of fat interferes with the liver's ability to use insulin and negatively affects lipoprotein metabolism by the liver. These upper-body adipose cells are not just storage depots; they are metabolically active cells that release many hormones and other peptides, called adipokines, involved in long-term energy regulation. ---When they fill with excess fat, the cells become dysfunctional, resulting in inflammation, insulin resistance, and other adverse health conditions leading to chronic disease. ---High blood testosterone levels encourage upper-body obesity, as does excessive alcohol intake, and smoking. ---This pattern of fat storage is commonly known as the apple shape (large abdomen and small buttocks and thighs). ---Upper-body obesity is assessed by measuring the circumference of the abdomen at the waist. ---A waist circumference of: ***more than 40 inches (102 centimeters) in men and ***more than 35 inches (88 centimeters) in women indicates risk for upper-body obesity ---If BMI is also 25 or more, health risks are significantly increased. Lower-body (gymnoid) obesity: ---Estrogen and progesterone encourage lower-body (gynoid) obesity—the typical female pattern. ---The small abdomen and much larger buttocks and thighs give a pear shape appearance. ---Fat deposited in the lower body is not mobilized as easily as android fat cells and often resists being released. ---After menopause, blood estrogen levels fall, encouraging greater upper-body fat distribution and raising the risk of chronic disease dramatically for postmenopausal females. Health problems associated with excess body fat and their likely causes: ---Surgical complications: Increased anesthesia needs; greater risk of wound infections (decreased immune function) ---Pulmonary disease and sleep disorders: Excess weight stressing the lungs and pharynx ---Type 2 diabetes: Enlarged adipose (fat) cells poorly bind insulin and inadequately respond to insulin signals; reduced synthesis of factors that promote insulin action and increased synthesis of factors that counter insulin action ---Hypertension: Increased miles of blood vessels found in the adipose tissue, increased blood volume, and increased resistance to blood flow related to hormones made by adipose cells ---Cardiovascular disease (e.g., coronary heart disease and stroke): Increased LDL cholesterol and triglycerides; reduced HDL cholesterol; increased synthesis of blood clotting and inflammatory factors by enlarged adipose cells; potential for altered heart rhythm ---Bone and joint disorders (including gout): Excess pressure placed on knees, ankles, and hip joints ---Gallstones: Increased cholesterol content of bile ---Skin disorders: Accumulation and trapping of moisture and microorganisms in tissue folds ---Various cancers: Estrogen and other hormones contribute to tumor growth by adipose cells; increased hyperinsulinemia or insulin resistance; systemic inflammation associated with cancer risk; excess calorie intake may encourage tumor development (animal studies) ---Shorter stature (in some forms of obesity): Earlier onset of puberty ---Pregnancy risks: More difficult delivery; increased birth defects and gestational diabetes; greater anesthesia needs ---Reduced physical agility and increased risk of accidents and falls: Excess weight impairs physical movement and gait ---Menstrual irregularities and infertility: Hormone imbalances; insulin resistance; increased oxidative stress ---Vision problems: Higher rates of cataracts and other eye disorders ---Premature death: Comorbidities and greater risk factors for numerous chronic diseases and complicationsInfectionsReduced immune system activity ---Liver damage and eventual failure: Excess fat accumulation in the liver (fatty liver) ---Erectile dysfunction in men: Low-grade inflammation caused by reduced function of the cells lining the blood vessels and impaired blood circulation

Identify food sources of different types of lipids including saturated , monounsaturated, and polyunsaturated fatty acids, and cholesterol (5) 5.3 Fats and Oils in Foods (pp. 168-176)

The foods highest in fat (and therefore energy density) include salad oils and spreads such as butter, margarine, and mayonnaise. All of these foods contain close to 100% of calories as fat. Other high-fat foods include nuts, bologna, avocados, and bacon, which have about 80% of calories as fat Next, peanut butter and cheddar cheese have about 75% of calories from fat. Marbled steak and hamburgers (ground chuck) have about 60% of calories from fat chocolate bars, ice cream, doughnuts, and whole milk have about 50% of calories as fat Eggs, pumpkin pie, and cupcakes have 35%, as do lean cuts of meat such as top round, ground round, and sirloin Bread contains about 15% of calories as fat Foods such as cornflakes, sugar, and fat-free milk have essentially no fat. Types of fat: a fat or an oil is classified as saturated, monounsaturated, or polyunsaturated based on the type of fatty acids present in the greatest concentration Fats in foods that contain primarily saturated fatty acids are solid at room temperature, especially if the fatty acids have long carbon chains as opposed to shorter versions fats containing primarily polyunsaturated or monounsaturated fatty acids (regardless of the length of the carbon chain) are usually liquid at room temperature Almost all fatty acids in the body and in foods are long-chain fatty acids. Saturated Fat food sources: ---Animal fats are the chief contributors of saturated fatty acids to the North American diet (dairy and meat) ---Palm oil and coconut oil (two plant oils) ---AMDR urges limited saturated fat intake Unsaturated Fat food sources: ---most other plant oils are rich in unsaturated fatty acids (canola oil, olive oil, and peanut oil) Polyunsaturated fatty acids food sources: ---Corn, cottonseed, sunflower, soybean, and safflower oils Essential fatty acids food sources: ---linoleic acid—the essential omega-6 fatty acid---chicken, safflower, sunflower, corn, and cottonseed oils, as well as nuts and seeds ----alpha-linolenic acid (the essential omega-3 fatty acid)---flax seeds and walnuts, oils from perilla seeds, chia seeds, canola, and soybeans Omega 3 fatty acids food sources: ---Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)---non-essential fatty acids ---fatty fish such as salmon, tuna, sardines, anchovies, striped bass, catfish, herring, mackerel, trout, and halibut ---AMDR recommends two servings of fatty fish per week for optimal cardiovascular health ---some types of fish can be a source of mercury, which is toxic in high amounts---shark, swordfish, king mackerel, tilefish, marlin, orange roughy, and bigeye, or ahi, tuna ---better options---Salmon, sardines, herring, and albacore or yellowfin tuna ---benefits of fish intake, especially in reducing the risk of cardiovascular disease, outweigh the possible risks of mercury contamination Phospholipids food sources: ---ex. lecithin--a component in egg yolks--used as an emulsifier in these and other products because of its ability to keep mixtures of lipids and water from separating ---Wheat germ, peanuts, egg yolks, soybeans, and organ meats Sterols food sources: ---Cholesterol is found only in animal foods ---One large egg yolk contains about 185 milligrams of cholesterol ---Eggs, meats, and whole milk are our main dietary sources of cholesterol ---Foods of plant origin are naturally cholesterol free, but they may contain plant sterols ---Some plant sterols have blood cholesterol-lowering properties Foods that contain hidden fat include whole milk, pastries, cookies, cake, cheese, hot dogs, crackers, French fries, and ice cream look on the food label ---total fat, saturated fat, and trans fat. ---ingredients--presence of animal fats (e.g., bacon, beef, ham, lamb, pork, chicken, and turkey fats), dairy fats (e.g., butter and cream), egg and egg-yolk solids, nuts, vegetable oils, and partially hydrogenated shortening or vegetable oil ---ingredients listed by weight---If fat is one of the first ingredients listed, you are probably looking at a high-fat product

Describe the components of energy expenditure and the factors that affect BMR. (5) 7.1 Energy Balance, Energy Output (pp. 241-243), Figure 7-6

The most reliable and successful weight loss comes from hard work and commitment. A combination of decreased calorie intake, increased physical activity, and behavior modification is considered to be the most reliable treatment for the overweight condition the prevention of the overweight condition in the first place is the most successful approach Positive and Negative energy balance: ---Energy input (calories from food intake) = Energy output (metabolism; digestion, absorption, and transport of nutrients; physical activity) ---The balance of energy (or calories, measured in kilocalories) on the two sides of this equation can influence energy stores, especially the amount of triglyceride stored in adipose tissue. Positive Energy balance: ---When energy input is greater than energy output, the result is positive energy balance. ---The excess calories consumed are stored in the body, which results in weight gain. ---Normal and healthy during pregnancy and lactation (breastfeeding) ------a surplus of calories supports the developing fetus. ------Infants and children also require a positive energy balance for normal growth and development during youth and puberty. ---Unhealthy in adults ------even a small positive energy balance typically results in fat storage rather than muscle and bone and, over time, this can contribute to increased body fatness Negative Energy Balance: ---On the other hand, if energy input is less than energy output, there is a calorie deficit and negative energy balance results. ---A negative energy balance is necessary for successful weight loss. ---It is important to realize that when we lose weight, we typically lose some lean tissue in addition to adipose tissue. Maintenance of Energy balance: ---The maintenance of energy balance while at an optimal weight substantially contributes to optimal health and well-being by minimizing the risk of developing many common health problems associated with increased body fat. ---Adulthood is often a time of subtle weight which can lead to obesity and a greater risk of disease if left unchecked. ---Aging does not directly cause weight gain; rather the problem stems from a pattern of excess energy intake coupled with limited physical activity and slower metabolism. Factors affecting energy balance: Energy intake: ---Energy needs are met by dietary intake, represented by the number of calories consumed each day. ---Determining the appropriate amount and type of food to meet our energy needs is a challenge for many of us. ---Our desire to consume food and the ability of our bodies to use it efficiently are survival mechanisms that have evolved with humans. ---The overabundance of energy-dense food and high-calorie beverages lead to overconsumption and excess stores of body fat ---Bomb colorimeter: The number of calories in a food is determined with an instrument called a bomb calorimeter. ------The bomb calorimeter measures the amount of calories (kilocalories--the amojnt of heat needed to raise the temp of 1 kilogram of water by 1 degree C) coming from carbohydrate, fat, protein, and alcohol. -------Recall that carbohydrates and proteins each yield 4 kcal per gram, fats yield 9 kcal per gram, and alcohol yields 7 kcal per gram. ---------These calorie estimates have been adjusted for: (1) the body's ability to digest the food; and (2) substances in food, such as fibrous plant parts, that burn in the bomb calorimeter but are not absorbed by our bodies, so they do not provide calories to the human body. Energy output: ---The body uses energy for three general purposes: (1) basal metabolism; (2) physical activity; and (3) digestion, absorption, and processing of ingested nutrients. A fourth minor form of energy output, known as adaptive thermogenesis, refers to energy expended during fidgeting or shivering when cold Basal Metabolism (or BMR): ---expressed as basal metabolic rate (BMR) and represents the minimal amount of calories expended in a fasting state to keep a resting, awake body alive in a warm, quiet environment. ---For a sedentary person, basal metabolism accounts for about 60% to 75% of total energy use by the body. ---Some of the processes that utilize energy include the beating of the heart, respiration by the lungs, and the activity required by other organs, such as the liver, brain, and kidney. ---It does NOT include energy used for physical activity or digestion, absorption, and processing of recently consumed nutrients. ---If the person is not fasting or completely rested, the term resting metabolism is used and expressed as resting metabolic rate (RMR). ------An individual's RMR is typically higher than his or her BMR Calculating BMR: ---To see how basal metabolism contributes to energy needs, consider a 130-pound woman. ---First, knowing that there are 2.2 pounds (lbs) for every kilogram (kg), convert her weight into metric units: 130 lb ÷ 2.2 lb/kg = 59 kg Then, using a rough estimate of BMR of 0.9 kcal per kilogram per hour for an average female (note 1 kcal per kilogram per hour is used for an average male), and calculate her BMR: 59 kg × 0.9 kcal/kg = 53 kcal/hr Finally, use this hourly BMR to find her BMR for an entire day (24 hours): 53 kcal/hr × 24 hr = 1272 kcal/day These calculations provide an estimate of basal metabolism, as it can vary as much as 25% to 30% among individuals. Factors increasing BMR (or energy output): ---the amount of lean body mass a person has is the most important. ------Persons with higher amounts of lean body mass have a higher BMR because lean tissue is more metabolically active than fat. ------the lean tissue, therefore, requires more energy to support its activity. ------Although overweight and obese persons have an increased amount of body fat, they also typically have a high amount of lean body mass to support their weight and therefore a high BMR to go along with it ---physical activity ------Physical activity increases energy expenditure above and beyond basal energy needs by as much as 15% to 35%. The calorie expenditure from physical activity varies widely among people. ---thermic effect of food (TEF) ------the body uses energy to digest food, and absorb and further process the nutrients recently consumed. Energy used for these tasks is referred to as the thermic effect of food (TEF). ------equates to between 5 and 10 kcal extra for every 100 kcal needed for basal metabolism and physical activity. If your daily calorie intake was 3000 kcal, for example, TEF would account for 150 to 300 kcal ------Food composition influences TEF. For example, the TEF value for a protein-rich meal is 20% to 30% of the calories consumed and is higher than that of a carbohydrate-rich (5% to 10%) or fat-rich (0% to 3%) meal ---------Lean protein foods such as chicken breast, egg whites, and whitefish have the highest TEF at almost 30%. This means that if you eat 100 kcal of chicken breast, almost 30 of those calories are burned off just to digest it ------------this is because it takes more energy to metabolize amino acids (from protein sources) into fat than to convert glucose (from carbohydrate sources) into glycogen or transfer absorbed fat into adipose stores ---adaptive thermogenesis ------the increase in nonvoluntary physical activity triggered by reflex responses (versus intentional physical activity) ------shivering when cold, fidgeting, maintenance of muscle tone, and maintaining body posture when not lying down ------The contribution of thermogenesis to overall calorie output is fairly small. The combination of BMR and TEF accounts for 70% to 85% of energy used by a sedentary person. The remaining 15% to 30% is used mostly for physical activity, with a small amount used for thermogenesis. Persons of the same body weight can have different amounts of LBM and body fat and, therefore, have varying energy needs. ---two women 130 lbs--- ------1 has 20% body fat (26 lb fat) and 114 lb lean body mass---has a higher BMR ------1 has 30% body fat (39 lb fat) and 91 lb lean body mass Factors decreasing basal metabolism (or energy output): ---a low calorie intake, such as an extreme diet regime, decreases basal metabolism by about 10% to 20% (about 150 to 300 kcal per day) as the body shifts into a conservation or starvation mode. ---effects of aging also make weight maintenance a challenge--As lean body mass slowly and steadily decreases, basal metabolism declines 1% to 2% for each decade past the age of 30.

Describe the structure of proteins Explain why adequate amounts of all the essential amino acids are required for protein synthesis. (3) 6.1 Amino Acids - Building Blocks of Protein (pp. 204-205) 6.2 Protein Synthesis and Organization (pp. 206-208) and Figure 6-3

Aside from water, proteins form the major part of lean body tissue, totaling about 17% of body weight. Amino acids are compounds that serve as the building blocks for proteins. ---They are chemically unique in that they contain nitrogen along with carbon, oxygen, and hydrogen ---Plants combine nitrogen from the soil with carbon and other elements to form amino acids. They then link these amino acids together to make proteins Proteins are an essential part of a healthy eating pattern because they supply nitrogen in a form we can readily use, namely, amino acids Proteins are crucial to the regulation and maintenance of the body. ---Body functions such as blood clotting, fluid balance, hormone and enzyme production, visual processes, transport of many substances in the bloodstream, and cell repair require specific proteins. Formation of these body proteins begins with amino acids from both the protein-containing foods we eat and those synthesized from other compounds within the body. Proteins can also be broken down to supply energy for the body—on average, 4 kcal per gram Your body uses 20 different amino acids to function Although all of these commonly found amino acids are important, 11 (alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine) are considered nonessential with respect to our eating patterns. Structure of amino acids: ---Amino acids are formed mostly of carbon, hydrogen, oxygen, and nitrogen. ---The various amino acids used to make proteins are slight variations of generic amino acid with different chemical makeups ---Each amino acid has an "acid" group, an "amino" group, and a "side chain" or R group specific to the amino acid. ---The R group on some amino acids has a branched shape, like a tree. These so-called branched-chain amino acids are leucine, isoleucine, and valine ------The branched-chain amino acids are the primary amino acids that promote and signal protein synthesis and turnover in muscles Essential Amino Acids: ---The nine amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) the body cannot make in sufficient amounts or at all are known as essential. ---The essential amino acids must be obtained from foods because body cells cannot make the needed carbon-based foundation of the amino acid, cannot put a nitrogen group on the needed carbon-based foundation, or just cannot do the whole process fast enough to meet body needs. ---If you do not eat enough essential amino acids, your body first struggles to conserve what essential amino acids it can. ------eventually your body slows production of new proteins until at some point, you will break protein down faster than you can make it...When that happens, health deteriorates. ---Animal sources of protein, such as meat and dairy products, and plant sources of protein, such as beans, nuts, and seeds, can supply us with an adequate amount of both the essential and nonessential amino acid building blocks needed to maintain good health. ------Both nonessential and essential amino acids are present in foods that contain protein. ---The essential amino acid in smallest supply in a food or meal in relation to body needs becomes the limiting factor or limiting amino acid because it limits the amount of protein the body can synthesize. ---Typically, 50% of the amino acids in dietary proteins are essential. Fortunately, adults need only about 11% of their total protein requirement to be supplied by them. ---Some of the nonessential amino acids, which are usually synthesized in the body, can become essential during times of rapid growth, disease, or metabolic stress. ------For example, the need for amino acids to promote healing during recovery from surgery or burns is so high that the activity of enzymes that synthesize nonessential amino acids cannot keep up with demands. ------Arginine and glutamine are two examples of conditionally essential amino acids Protein Synthesis and Organization: ---Within body cells, amino acids are linked together by chemical bonds—technically called peptide bonds—to form proteins ---Peptide bonds form between the amino group of one amino acid and the acid (carboxyl) group of another. ------Through peptide bonding of amino acids, cells can synthesize: ---------dipeptides (joining of two amino acids) ---------tripeptides (joining of three amino acids) ---------oligopeptides (joining of four to nine amino acids) ---------polypeptides (joining of 10 or more amino acids). ------------Most proteins are polypeptides ranging from about 50 to 2000 amino acids. ---The body can synthesize many different proteins by linking together the 20 common types of amino acids with peptide bonds. ------These bonds are difficult to break, but heat, acids, enzymes, and other agents are able to do so during cooking and chemical digestion. Synthesis: 1) DNA contains the information necessary to produce the proteins ---DNA is present in the nucleus of the cell and contains coded instructions for protein synthesis (i.e., which specific amino acids are to be placed in a protein and in which order) ---Protein synthesis, however, takes place in the cytoplasm of the cell, not in the nucleus -----The DNA code used for synthesis of a specific protein must be transferred from the nucleus to the cytoplasm to allow for protein synthesis. This transfer is the job of messenger RNA (mRNA) 2) Transcription or copying of a segment of DNA results in mRNA, a copy of the info in DNA needed to make a protein ---During transcription, enzymes in the nucleus first read the code (a gene) on a DNA base sequence that encodes one or more proteins and then transcribe that information into a single-stranded mRNA molecule that is ready to leave the nucleus 3) the mRNA leaves the nucleus and goes to a ribosome ---Once in the cytoplasm, mRNA travels to the ribosomes. ---The ribosomes read the mRNA code and translate those instructions to produce a specific protein. ---During translation, amino acids are added one at a time to the growing polypeptide chain, according to the instructions on the mRNA. 4) Amino acids, the building blocks of proteins, are carried to the ribosome by tRNAs containing the code that matches that on the mRNA ---Another key participant in protein synthesis, transfer RNA (tRNA), is responsible for bringing the specific amino acids to the ribosomes as needed during protein synthesis. ---Energy input is required to add each amino acid to the chain, making protein synthesis "costly" in terms of calorie use 5) in the process of translation, the info contained in mRNA is used to determine the number, types, and arrangement of amino acids in the protein ---Once synthesis of a polypeptide is complete, it twists and folds into the appropriate three-dimensional shape of the intended protein. ---These structural changes occur based on specific interactions among the amino acids on the polypeptide chain. ---Some polypeptides, such as the hormone insulin, also undergo further changes in the cell before they are functional. Protein organization: ---Through the bonding together of the 20 common types of amino acids into various combinations, the body synthesizes thousands of different proteins. ---The sequential order of the amino acids then ultimately determines the protein's shape. ---An important point is that only correctly positioned amino acids can interact and fold properly to form the intended shape for the protein. ---The resulting unique, three-dimensional form goes on to dictate the function of each particular protein. ---If it lacks the proper structure, a protein cannot function. ---The relationship between DNA and the proteins eventually produced by a cell is very important---A defect in the DNA can dictate that a wrong amino acid will be built into the sequence of the body proteins ---If the DNA code contains errors, a genetic defect and an incorrect mRNA will be produced. ---The ribosomes will then read this incorrect message, and an incorrect amino acid will be added, resulting in an incorrect polypeptide chain being produced. ------Example: sickle cell disease, or sickle cell anemia---caused by a mutation in the genetic code for hemoglobin, a protein that carries oxygen in red blood cells---can cause severe bone and joint pain, abdominal pain, headache, convulsions, paralysis, and even death due to the lack of oxygen ---Genetic engineering has begun to be used to correct gene defects in humans by placing the correct DNA code in the nucleus so that the correct protein can be made by the ribosomes. Denaturation of proteins: ---The process of altering the three-dimensional structure of a protein is called denaturation ---Changing the shape of a protein often destroys its ability to function normally such that it loses its biological activity. ---Exposure to acid or alkaline substances, heat, or agitation (e.g., whipping egg whites) can alter a protein's structure, leaving it uncoiled or otherwise deformed. ---Denaturation of dietary proteins does not alter their nutritional value and is a necessary part of digestion and other body processes ---the heat produced during cooking starts the denaturation of some proteins ---After food is ingested, the secretion of stomach acid denatures many forms of proteins in foods such as some bacterial proteins, plant hormones, and many active enzymes, making it safer to eat. ---Denaturation enhances digestion because the unraveling increases exposure of the polypeptide chain to digestive enzymes. ---Denaturing proteins in some foods can also reduce their tendencies to cause allergic reactions.

List and describe the roles of protein in the body and explain protein balance. (4) 6.5 Putting Proteins to Work in the Body (pp. 216-219) 6.6 Protein Needs (pp. 220-224), Figure 6-14

Proteins function in many crucial ways in human metabolism and in the formation of body structures ------We rely on foods to supply the amino acids needed to form these proteins; however, only when we also eat enough carbohydrate and fat can food proteins be used most efficiently. ------If we do not consume enough total calories to meet needs, proteins are broken down to supply energy to cells. ------This renders the amino acids unavailable for growth and repair of body tissues ---If you fail to consume an adequate amount of protein for weeks at a time, many metabolic processes slow down because the body does not have enough amino acids available to build the proteins it needs. ------For example, the immune system no longer functions efficiently when it lacks key proteins, thereby increasing the risk of infections, disease, and death. ---The amino acid pool in a cell can be used to form body proteins, as well as a variety of other possible compounds. ------Every cell contains protein: Muscles, connective tissue, mucus, blood-clotting factors, transport proteins in the bloodstream, lipoproteins, enzymes, immune antibodies, some hormones, visual pigments, and the support structure inside bones. ------Excess protein in the diet does not enhance the synthesis of these body components, but eating too little protein can prevent it. ---Protein turnover (amino acid metabolism) is a process by which a cell can respond to its changing environment by making proteins that are needed and disassembling proteins that are not needed ------During a 24-hour period, an adult turns over (makes and degrades) about 250 grams of protein, recycling many of the amino acids. ------If a person's diet is low in protein for a long period, the processes of rebuilding and repairing body proteins will slow down. ---------Over time, skeletal muscles, blood proteins, and vital organs such as the heart and liver will decrease in size or volume. Only the brain resists protein breakdown. Proteins also contribute to the body: ---Blood proteins help maintain body fluid balance. With an inadequate consumption of protein, the concentration of proteins in the bloodstream drops below normal. Excessive fluid then builds up in the surrounding tissues because the counteracting force produced by the smaller amount of blood proteins is too weak to pull enough of the fluid back from the tissues into the bloodstream. As fluids accumulate in the tissues, the tissues swell, causing edema. ---Proteins help regulate acid-base balance in the blood...Proteins located in cell membranes pump chemical ions in and out of cells. The ion concentration that results from the pumping action, among other factors, keeps the blood slightly alkaline. In addition, some blood proteins are especially good buffers in the bloodstream. Buffers are compounds that maintain acid-base conditions within a narrow range. If this doesn't happen, blood acidity issues can happen. ---Many hormones, our internal body messengers, are proteins and therefore require amino acids for synthesis. Some hormones, such as the thyroid hormones, are made from only one type of amino acid, tyrosine. Insulin, on the other hand, is a hormone composed of 51 amino acids. Almost all enzymes are proteins or have a protein component. ---Proteins are a key component of cells within the immune system. Antibodies are proteins produced by one type of white blood cell. These antibodies can bind to foreign proteins in the bloodstream—an important step in removing invaders from the body. Without sufficient dietary protein, the immune system lacks the materials needed to function properly. For example, a low-protein status can turn an infection such as measles into a fatal disease for a malnourished child. ---Protein can form glucose, but only in "starvation mode". If you do not consume enough carbohydrate to supply the glucose, your liver (and kidneys, to a lesser extent) will be forced to make glucose from amino acids present in body tissues ---Proteins supply little energy for a person at a healthy weight. Two situations in which a person does use protein to meet energy needs are during prolonged exercise and during calorie restriction, as with a weight-loss diet. ------In these cases, the amino group (−NH2) from the amino acid is removed, and the remaining carbon skeleton is metabolized for energy needs. When the carbon skeletons of amino acids are metabolized to produce glucose or fat, ammonia (NH3) is a resulting waste product. The ammonia is converted into urea and excreted in the urine. ---------Under most conditions, cells primarily use fats and carbohydrates for energy needs. Although proteins contain the same amount of calories (on average, 4 kcal per gram) as carbohydrates, proteins are a costly source of calories, considering the amount of processing the liver and kidneys must perform to use this calorie source. ---Compared to the other macronutrients, proteins provide the highest feeling of satiety after a meal. Meeting protein needs is important, and exceeding needs somewhat may provide an additional benefit when dieting to lose weight ---People who are not growing need to eat only enough protein to match whatever they lose daily from protein breakdown. ------The amount of breakdown can be determined by measuring the amount of urea and other nitrogen-containing compounds in the urine, as well as losses of protein from feces, skin, hair, nails, and so on ---people need to balance protein intake with such losses to maintain a state of protein equilibrium, also called protein balance Positive protein balance: ---When a body is growing or recovering from an illness or injury, it needs a positive protein balance to supply the raw materials required to build new tissues. ---To achieve this, a person must eat more protein daily than he or she loses. ---In addition, the hormones insulin, growth hormone, and testosterone all stimulate positive protein balance. ---Resistance exercise (weight training) also enhances positive protein balance. Negative protein balance: ---Consuming less protein than needed leads to negative protein balance, such as when acute illness reduces the desire to eat, causing a person to lose more protein than he or she consumes. Protein equilibrium: ---For healthy people, the amount of dietary protein needed to maintain protein equilibrium (where intake equals losses) can be determined by increasing protein intake until it equals losses of protein and its related breakdown products (e.g., urea). ---Calorie needs must also be met so that amino acids are not diverted for use as energy. Recommendations: ---The Dietary Guidelines for Americans recommend a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), nuts, seeds, and soy products. ---The following shifts are also recommended to increase variety in protein food choices and to make more nutrient-dense choices: ------Increase the amount and variety of seafood consumed by choosing seafood in place of some meat and poultry. ------Increase seafood intake, but the foods to be replaced depend on the individual's current intake from the other protein subgroups. ------Incorporate seafood as the protein foods choice in meals twice per week in place of meat, poultry, or eggs. ------Use legumes or nuts and seeds in mixed dishes instead of some meat or poultry. ------Shift to nutrient-dense options, including lean and lower sodium options, to improve the nutritional quality of protein food choices and support healthy eating patterns. ------Some individuals, especially teen boys and adult men, also need to reduce overall intake of protein foods by decreasing intakes of meats, poultry, and eggs and increasing amounts of vegetables or other under-consumed food groups ---The RDA for the amount of protein required for nearly all adults to maintain protein equilibrium is 0.8 gram of protein per kilogram of healthy body weight. ---Requirements are higher during periods of growth, such as pregnancy and infancy, and an increased protein intake of more than 1.0 grams per kilogram of body weight per day has been recommended for older adults ---The RDA for protein translates into about 10% of total calories. ---Many experts recommend up to 15% of total calories as protein to provide flexibility in diet planning and to allow for the variety of protein-rich foods typically consumed. ---The Dietary Guidelines encourage the consumption of protein-rich foods such as beans, nuts, seeds, fat-free milk, and seafood. ---The Food and Nutrition Board has set an upper range for protein intake at 35% of calories consumed. ---Studies have found that consuming at least 20 to 30 grams of protein at a given meal has positive effects on muscle protein synthesis, compared with spreading the same total amount of protein across multiple small meals. ---Researchers now recommend that adults consume at least 30 grams of protein at more than one meal in order to maintain healthy muscles and bones. ---Protein at breakfast is especially critical to regulate appetite and daily food intake and to replenish body proteins after an overnight fast ---An increased daily protein intake of more than 1.0 grams per kilogram for older adults is recommended ------Specific recommendations are for older adults to consume meals with greater than 20 grams of protein, including more than 2.2 grams of leucine, to optimize protein synthesis in skeletal muscle, and resistance exercise enhances the protein synthesis response, especially muscle growth. Our bodies cannot store excess protein once it is consumed, so the excess amino acids are stripped of the nitrogen-containing amino group and may be turned into glucose or ketone bodies and contribute to a positive energy balance, which would be undesirable if weight loss is the goal Protein and amino acid supplements are used primarily by those trying to lose weight and by athletes hoping to build muscle. ---The amino acids methionine, cysteine, and histidine are most likely to cause toxicity when consumed in large amounts. ---Due to this potential for imbalances and toxicities, the best advice to ensure adequacy is to stick to whole foods as sources of amino acids rather than supplements. ---Amino acid supplements also have a disagreeable odor and flavor and are much more expensive than food protein.

Define atherosclerosis and identify dietary, lifestyle, blood lipid levels, and blood pressure measurements that are helpful or harmful for cardiovascular disease risk. (4) 5.7 Recommendations for Fat Intake (pp. 185-189) 5.8 Nutrition and Your Health: Lipids and Cardiovascular Disease (pp. 191-195) and Figure 5-16.

Recommendations: total fat intake should be 20% to 35% of total calories ---equates to 44 to 78 grams per day for a person who consumes 2000 kcal daily. ---doesn't apply to infants and toddlers linoleic acid and alpha-linolenic acid recommendations: only need to consume 2 to 4 tablespoons of plant oil each day, which equates to roughly 5% of our total calories ----cooking oils, salad dressings, nuts and seeds, vegetables, and whole grain breads. ---Even a low-fat diet will provide enough essential fatty acids if it follows a balanced plan such as MyPlate. To reduce risk for cardiovascular disease, the AHA recommends reducing trans fat and limiting saturated fat to no more than 5% to 6% of total calories. These are the primary fatty acids that raise LDL the latest guidelines set no specific limits on dietary cholesterol because dietary cholesterol intake has little impact on blood cholesterol levels. ---Instead, evidence shows that saturated fat and trans fat have the greatest impact on blood lipids. ------That doesn't mean you should eat limitless quantities of cholesterol-rich foods though... As it turns out, rich food sources of cholesterol are usually sources of saturated fat, as well. ------Thus, as you reduce the saturated fat in your diet, you will likely reduce your cholesterol intake, too. Atherosclerosis: a disease of the arteries characterized by the deposition of plaques of fatty material on their inner walls ---first develops to repair damage in a vessel lining ---A healthy blood vessel is smooth and flexible so that blood can easily move through it. ------Damage to a blood vessel--- smoking, diabetes, high blood pressure, high blood cholesterol, infection—basically any process that causes inflammation in the body ---can be seen in arteries throughout the body. ------The damage develops especially at points where an artery branches into two smaller vessels. ------ A great deal of stress is placed on the vessel walls at these points due to changes in blood flow. ---Once blood vessel damage has occurred, plaque continues to build up at the site of initial damage. ------The rate of plaque buildup is directly related to the amount of LDL in the blood. Specifically, oxidized LDL appears to be responsible for plaque formation. ---The body also sends white blood cells called macrophages to the location of the cholesterol accumulation on the blood vessel wall. ------In an attempt to destroy it, the macrophage surrounds the fatty deposit and produces lipid-loaded foam cells. ------Over years, the blood vessels stiffen, so they cannot dilate or constrict to accommodate normal changes in blood pressure throughout the day. ------The buildup of plaque can restrict or block blood flow. ------Some plaques can become unstable and tear away from the artery. ---------If they rupture, a blood clot will form inside the artery, and within minutes, blood flow is cut off, resulting in a heart attack or stroke Cardiovascular disease: typically involves the coronary arteries and, thus, frequently the term coronary heart disease (CHD) or coronary artery disease (CAD) is used Typical forms: coronary heart disease and strokes Causes: ---autopsies of young adults under 20 years of age have shown that many of them had atherosclerotic plaque in their arteries ------plaque buildup can begin in childhood and continue throughout life, although it usually goes undetected for some time ---inadequate blood circulation in the heart and brain related to buildup of plaque ------When blood flow via the coronary arteries surrounding the heart is interrupted, the heart muscle can be damaged. A heart attack, or myocardial infarction, may result ---------A heart attack may cause the heart to beat irregularly or to stop. ---------About 25% of people do not survive their first heart attack. ---------Similarly, if blood flow to parts of the brain is interrupted long enough, part of the brain dies, causing a cerebrovascular accident, or stroke. ---------Aspirin helps to reduce the blood clotting that leads to a heart attack. Risk Factors: (The term risk factor is not equivalent to "cause of disease"; nevertheless, the more of these risk factors one has, the greater the chances of ultimately developing cardiovascular disease) ---total blood cholesterol over 200 milligrams per 1 deciliter of blood (200 mg/dl; 1 deciliter equals 100 milliliters) ---smoking---greatly increases the expression of a person's genetically linked risk for cardiovascular disease, even if one's blood lipids are low, and makes blood more likely to clot ---hypertension---systolic blood pressure over 139 (millimeters of mercury) and diastolic blood pressure over 89 indicate hypertension. Healthy blood pressure values are less than 120 and 80, respectively. ---diabetes---virtually guarantees development of cardiovascular disease...Insulin increases cholesterol synthesis in the liver, in turn increasing LDL in the bloodstream. Negates any female advantage ---HDL cholesterol---under 40 mg/dl, especially when the ratio of total cholesterol to HDL cholesterol is greater than 4:1 (3.5:1 or less is optimal)... A value of 60 mg/dl or more is especially protective. Before menopause, women often have high HDL, which affords them some protection against cardiovascular disease ---age---Men over 45 years and women over 55 years are at heightened risk ---family history---especially before age 50 ---Blood triglycerides---200 mg/dl or greater in the fasting state increase risk...Triglyceride levels less than 100 mg/dl are optimal ---obesity---(especially fat accumulation in the waist) increases risk in a variety of ways...Typical weight gain seen in adults is a chief contributor to the increase in LDL seen with aging, insulin resistance--creating a diabetes-like state and ultimately the disease itself, and also increased overall inflammation throughout the body. ---Inactivity---Exercise conditions the arteries to adapt to physical stress...Regular exercise also improves insulin action in the body, and the corresponding reduction in insulin output leads to a reduction in lipoprotein synthesis in the liver. ---Metabolic syndrome---abdominal obesity, high blood triglycerides, low HDL cholesterol, hypertension, poor blood glucose regulation (i.e., high fasting blood glucose), and increased blood clotting Helpful for cardiovascular disease risk... Dietary and Lifestyle: overall healthy eating pattern; appropriate body weight; and a desirable blood cholesterol profile, blood pressure, and blood glucose level Dietary: ---Eat a variety of nutritious foods from all the food groups, including: A variety of fruits and vegetables, Whole grains, Low-fat dairy products, Skinless poultry and fish, Nuts and legumes, Nontropical vegetable oils ---Eat less of the nutrient-poor foods: Limit foods and beverages that are high in calories but low in nutrients, and Limit the amount of saturated fat, trans fat, and sodium you eat. ---As you make daily food choices, base your eating pattern on these recommendations: Eat a variety of fresh, frozen, and canned fruits and vegetables without high-calorie sauces or added salt and sugars, Choose fiber-rich whole grains for most grain servings, Choose poultry and fish without the skin and prepare them in healthy ways, Eat a variety of fish (especially those rich in omega-3 fatty acids) at least twice a week, Select fat-free and low-fat dairy products, Avoid foods containing partially hydrogenated vegetable oils to reduce trans fat in your diet, Limit saturated fat and trans fat and replace them with monounsaturated and polyunsaturated fats, If you need to lower blood cholesterol, reduce saturated fats to no more than 5% to 6% of total calories, Cut back on beverages and foods with added sugars, Choose foods with less sodium and prepare foods with little or no salt, If you drink alcohol, drink in moderation (no more than 1 drink per day for women and no more than 2 drinks per day for men), Follow the AHA recommendations when you eat out and keep an eye on portion sizes. ---fish consumption: eat 2 or more servings of fatty fish each week. ------Fish is not only a rich source of omega-3 fatty acids but also a valuable source of protein and trace elements that may provide protective effects for the cardiovascular system. ------Broiled or baked fish is recommended rather than fried fish because frying may increase the ratio of omega-6 to omega-3 fatty acids and may produce trans fatty acids and oxidized lipid products that may increase cardiovascular disease risk. ------fish oil capsules can be safely substituted for fish if a person does not like fish ---------fish oil capsules should be limited for individuals who have bleeding disorders, take anticoagulant medications, or anticipate surgery because they may increase risk of uncontrollable bleeding and hemorrhagic stroke ---Mediterranean diet: ------The major sources of fat in the Mediterranean diet include liberal amounts of olive oil compared to a small amount of animal fat (from animal flesh, eggs, and dairy products). ------consume moderate alcohol (usually in the form of red wine, which contains many antioxidants), eat plenty of whole grains and few refined carbohydrates, and are also more physically active ---Vegetarian (vegan) diet: ------very low in fat, including only a scant quantity of vegetable oil used in cooking and the small amount of oils present in plant foods. ------Individuals restricting fat intake to 20% of calories should be monitored by a physician, as the resulting increase in carbohydrate intake can increase blood triglycerides in some people, which is not a healthful change. Over time, however, the initial problem of high blood triglycerides on a low-fat diet may self-correct. ------Among people following the Ornish plan, blood triglycerides initially increased but within a year fell to normal values as long as the individuals emphasized high-fiber carbohydrate sources, controlled (or improved) body weight, and followed a regular exercise program. ---Fat Quality vs Fat Quantity: ------it is usually not necessary to drastically lower the quantity of fat in your diet. ------We should aim to choose more foods that provide omega-3 fatty acids, while choosing fewer sources of saturated and trans fats. ------Simply selecting the reduced-fat versions of pastries, cookies, and cakes will not improve the quality of your diet...Often, extra sugar or salt has been added to these foods to compensate for losses of taste and texture. ------Instead, focus your efforts on choosing plant sources of fat more often than animal sources ---------Fruits, vegetables, and whole grains are usually low in total fat and saturated fat; the (mostly unsaturated) fats they do provide are accompanied by vitamin E, vitamin K, and a variety of health-promoting phytochemicals. Eat less of: ---grains: Pasta dishes with cheese or cream sauces, Croissants, Pastries, Doughnuts, Pie crust ---Vegetables: French fries, Potato chips, Vegetables cooked in butter, cheese, or cream sauces ---Fruit: fruit pies ---Dairy: Whole milk, Ice cream, High-fat cheese, Cheesecake ---Protein: Bacon, Sausage, Organ meats (e.g., liver), Egg yolks ---Fat and oils: butter, lard, stick margarine Eat more of: ---grains: Whole grain breads, Whole grain pasta, Brown rice, Air-popped popcorn ---vegetables: Fresh, frozen, baked, or steamed vegetables ---fruit: Fresh, frozen, or canned fruits ---dairy: Fat-free and reduced-fat milk, Low-fat frozen desserts (e.g., yogurt, sherbet, and ice milk), Reduced-fat/part-skim cheese ---protein: Fish, Skinless poultry, Lean cuts of meat (with fat trimmed away), Soy products, Egg whites/egg substitutes ---fat and oils: Plant oils, Tub margarine (with no trans fat) Lifestyle: ---restricting saturated fat intake even further to 5% to 6% of total kilocalories. ---scientific evidence links saturated and trans fat intake to higher levels of LDL, which promote plaque formation in blood vessels ---Even while cutting back on saturated and trans fat, overall fat intake should generally fall within the range of 20% to 35% of total kilocalories. ---This means you shouldn't simply cut fat out of your diet. ------Rather, you should choose unsaturated sources of fat, such as fatty fish, plant oils, nuts, and seeds, instead of foods rich in saturated fats. ---Remember that eating for heart health involves more than just fat ------Over the past few decades, evidence has accumulated that excessive intakes of added sugars have contributed to the high rate of cardiovascular disease. ------important to replace saturated fat with unsaturated fat, rather than with simple carbohydrates. ---Excessive intakes of refined carbohydrates and added sugars promote high levels of insulin, inflammation, and increased blood cholesterol ---Avoid LDL oxidation---Nutrients and phytochemicals that have antioxidant properties may reduce LDL oxidation. ------Fruits and vegetables are particularly rich in these compounds...Eating fruits and vegetables regularly is one positive step we can make to reduce plaque buildup and slow the progression of cardiovascular disease. ------Some fruits and vegetables particularly helpful in this regard include legumes (beans), nuts, dried plums (prunes), raisins, berries, plums, apples, cherries, oranges, grapes, spinach, broccoli, red bell peppers, and onions...tea, coffee, and dark chocolate ------foods are the best choices for antioxidants vs. antioxidant supplements (such as vitamin E) because large-scale studies have shown no decrease in cardiovascular disease risk with use of antioxidant supplements. ------Some rich food sources of plant sterols include wheat germ, sesame seeds, pistachios, and sunflower seeds--these have been clinically shown to reduce LDL (bad) cholesterol. Also Smart Balance® margarines and Minute Maid Heart Wise® orange juice ---exercise is an important way to modify risk for cardiovascular disease. Exercising for at least 45 minutes four times a week can increase HDL by about 5 mg/dl. Both regular aerobic exercise and resistance exercise are recommended ---medications offer a more aggressive approach to treating high cholesterol ------appropriate for people at heightened risk for this disease---Some factors to take into consideration include clinical evidence of atherosclerosis, very high LDL levels, or pre-existing diabetes or hypertension ------Medications work to lower blood cholesterol in several ways. -----aspirin, statins, selected cholesterol absorption inhibitors, resins, fibrates, niacin, combination drugs ---surgical treatment ------two most common surgical treatments for coronary artery blockage are percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft (CABG) ------PTCA involves the insertion of a balloon catheter into an artery. Once it is advanced to the area of the blockage, the balloon is expanded to crush the buildup of plaque. Afterward, the blood vessel may be held open with metal mesh, called a stent. ------CABG involves the relocation of a large vein-from the leg, for example-to bypass the blocked blood vessel.

Identify the strengths and limitations of vegetarian and meat-containing diets. (3) 6.8 Nutrition and Your Health: Vegetarian and Plant-Based Dietary Patterns (pp. 227-231)

Vegetarianism: There are many documented health benefits of following a vegetarian eating pattern. Studies show that death rates from some chronic diseases, such as certain forms of cardiovascular disease, hypertension, many forms of cancer, type 2 diabetes, and obesity, are lower for vegetarians than for nonvegetarians. Vegetarians often live longer, as shown in religious groups that practice vegetarianism the Dietary Guidelines for Americans and MyPlate emphasize a plant-based diet of whole grain breads and cereals, fruits, and vegetables. In addition, the American Institute for Cancer Research promotes "The New American Plate," which includes plant-based foods covering two-thirds (or more) of the plate and meat, fish, poultry, or low-fat dairy covering only one-third (or less) of the plate. Although these recommendations allow the inclusion of animal products, they are definitely more "vegetarian-like" than typical North American diets. it limits saturated fat and cholesterol intake, while encouraging a high intake of complex carbohydrates; vitamins A, E, and C; carotenoids; magnesium; and fiber. Some advocates of vegetarianism base their food preference upon the inefficient use of animals as a source of protein. Benefits: ---Disease prevention ------First, the plant foods we eat contain no cholesterol nor trans fat and little saturated fat ---------a vegan diet coupled with regular exercise and other lifestyle changes can lead to a reversal of atherosclerotic plaque in various arteries in the body. ---------Beans and nuts contain soluble fiber, which binds to cholesterol in the small intestine and prevents it from being absorbed by the intestinal cells ---------due to the activity of some phytochemicals, foods made from soybeans can lower production of cholesterol by the liver ---------The major types of fat in plant foods are monounsaturated and polyunsaturated fats ---------heart-protective compounds in plant foods--- Some of the phytochemicals may help to prevent blood clots and relax the blood vessels. Nuts are an especially good source of nutrients implicated in heart health, including vitamin E, folate, magnesium, and copper ------cancer prevention ---------numerous phytochemicals in plant foods are also thought to aid in preventing cancers of the breast, prostate, and colon. ---------Many of the proposed anticancer effects of foods containing plant protein are through antioxidant mechanisms ------diabetes control ---------Plants also may be particularly good sources of protein for people with diabetes or impaired glucose tolerance because the high fiber content of plant foods leads to a slower increase in blood glucose. ---------Frequent nut consumption may reduce the risk of gallstones, obesity, and type 2 diabetes. Many legumes are deficient in the essential amino acid methionine, whereas grains are limited in lysine. Eating a combination of legumes and grains, such as beans and rice, will supply the body with adequate amounts of all essential amino acids A pescovegetarian diet, one that includes aquatic animal protein, has been associated with a lower risk of colon cancer Problems with Vegetarianism: ---Low nutrients: ------Aside from amino acids, low intakes of certain micronutrients can be a problem for the vegan. ------At the forefront of nutritional concerns are riboflavin, vitamin B-12, iron, zinc, iodine, calcium, and vitamin D. ---Vitamin B-12: ------Vitamin B-12 only occurs naturally in animal foods. ------Vegans can prevent a vitamin B-12 deficiency by finding a reliable source of this vitamin, such as fortified soybean milk, ready-to-eat breakfast cereals, and special nutritional yeast grown on media rich in vitamin B-12. ------If dietary B-12 inadequacy persists, deficiency can lead to anemia, nerve damage, and mental dysfunction. ------These deficiency consequences have been noted in the infants of vegetarian mothers whose breast milk was low in vitamin B-12. ---Iron deficiency: ------For iron, the vegan can consume whole grains and ready-to-eat breakfast cereals, dried fruits and nuts, and legumes. ------The iron in these foods is not absorbed as well as iron in animal foods, but consuming these foods with a good source of vitamin C can enhance iron absorption. ------Cooking in iron pots and skillets can also add iron to food ---zinc deficiency: ------vegan can find zinc in whole grains (especially ready-to-eat breakfast cereals), nuts, and legumes, but phytic acid and other substances in these foods limit zinc absorption ------Breads are a good source of zinc because the leavening process (rising of the bread dough) reduces the influence of phytic acid. ---iodine deficiency: ------Iodized salt is a reliable source of iodine. It should be used instead of plain salt, both of which are found in U.S. supermarkets. ---Of all nutrients, calcium and vitamin D are the most difficult to consume in sufficient quantities for vegans: ------Fortified foods including fortified soy milk, fortified orange juice, calcium-rich tofu (check the label), and certain ready-to-eat breakfast cereals and snacks are the vegan's best option for obtaining these nutrients. ------In addition to fortified foods, alternate sources of vitamin D include some mushroom varieties and regular sun exposure. ------Green leafy vegetables and nuts also contain calcium, but the mineral is either not well absorbed or not very plentiful from these sources. ------Dietary supplements are another option. Special diet planning is always required because even a multivitamin and mineral supplement will not supply enough calcium to meet the needs for bone health ---omega-3 fatty acids: ------Fish and fish oils, abundant sources of these heart-healthy fats, are omitted from many types of vegetarian plans. ------Alternative plant sources of omega-3 fatty acids include canola oil, soybean oil, seaweed, microalgae, flax seeds, chia seeds, and walnuts

Describe functions of fat in the body and in foods (2) 5.6 Roles of Lipids in the Body (pp. 182-184) 5.3 Fats and Oils in Foods, Fat in Food Provides Some Satiety, Flavor, and Texture (pp. 172-173)

Roles: provide energy Storing energy for later use Insulating and protecting the body Transporting fat-soluble vitamins Regulating body processes Phospholipids in the body: Cholesterol in the body: Fats and oils in foods: ---Using food labels to identify fat ---fat in food provides some satiety, flavor, and texture ---fat-replacement strategies for reduced-fat foods

Describe protein digestion, absorption, and metabolism. (7) 6.4 Protein Digestion and Absorption (pp. 214-215) and Figure 6-12 6.6 Protein Needs (pp. 220-224) 6.5 Putting Proteins to Work in the Body (pp. 216-219), Figure 6-14

Protein digestion and absorption process: 1) partial protein digestion by stomach acid and the enzyme pepsin ---The enzymatic digestion of protein begins in the stomach. ---Proteins are first denatured by stomach acid. ---Pepsin, a major stomach enzyme for digesting proteins, then goes to work on the unraveled polypeptide chains. ---Pepsin breaks the polypeptide into shorter chains of amino acids because it can break only a few of the many peptide bonds found in these large molecules. ---The release of pepsin is controlled by the hormone gastrin. ---Thinking about food or chewing food stimulates gastrin release in the stomach. ---Gastrin then stimulates the stomach to produce acid and release pepsin. 2) pancreas releases enzymes that will further digest polypeptides in the small intestine. and 3) final digestion of peptides into single amino acids takes place mostly inside cells of the small intestine. Once in the small intestine, the partially digested proteins (and fats) trigger the release of the hormone cholecystokinin (CCK) from the walls of the small intestine. CCK causes the pancreas to release protein =-splitting enzymes, such as trypsin. ---The partially digested proteins move from the stomach into the small intestine along with the rest of the nutrients and other substances in a meal (chyme). ---Once in the small intestine, the partially digested proteins (and any fats accompanying them) trigger the release of the hormone cholecystokinin (CCK) from the walls of the small intestine. ---CCK, in turn, travels through the bloodstream to the pancreas, where it causes the pancreas to release protein-splitting enzymes, such as trypsin. ---These digestive enzymes further divide the chains of amino acids into segments of two to three amino acids and some individual amino acids. ---Eventually, this mixture is digested into amino acids, using other enzymes from the lining of the small intestine and enzymes present in the absorptive cells themselves. 4) amino acids absorbed into the portal vein and transported to the liver. From there, they enter the general bloodstream ---The short chains of amino acids and any individual amino acids in the small intestine are taken up by active transport into the absorptive cells lining the small intestine. ---Any remaining peptide bonds are broken inside intestinal cells to yield individual amino acids. ---They are water soluble, so the amino acids travel to the liver via the portal vein, which drains absorbed nutrients from the intestinal tract ---In the liver, individual amino acids can undergo several modifications, depending on the needs of various body tissues: ------Individual amino acids may be ---------(1) combined into the proteins needed by specific cells; ---------(2) broken down for energy needs; ---------(3) released into the bloodstream; or ---------(4) converted into nonessential amino acids, glucose, or fat. ---With excess protein intake, amino acids are converted into fat as a last resort. ---Except during infancy, it is uncommon for intact proteins to be absorbed from the digestive tract. 5) little dietary protein is present in feces Protein Metabolism: ---Proteins function in many crucial ways in human metabolism and in the formation of body structures ------We rely on foods to supply the amino acids needed to form these proteins; however, only when we also eat enough carbohydrate and fat can food proteins be used most efficiently. ------If we do not consume enough total calories to meet needs, proteins are broken down to supply energy to cells. ------This renders the amino acids unavailable for growth and repair of body tissues ---If you fail to consume an adequate amount of protein for weeks at a time, many metabolic processes slow down because the body does not have enough amino acids available to build the proteins it needs. ------For example, the immune system no longer functions efficiently when it lacks key proteins, thereby increasing the risk of infections, disease, and death. ---The amino acid pool in a cell can be used to form body proteins, as well as a variety of other possible compounds. ------Every cell contains protein: Muscles, connective tissue, mucus, blood-clotting factors, transport proteins in the bloodstream, lipoproteins, enzymes, immune antibodies, some hormones, visual pigments, and the support structure inside bones. ------Excess protein in the diet does not enhance the synthesis of these body components, but eating too little protein can prevent it. ---Protein turnover is a process by which a cell can respond to its changing environment by making proteins that are needed and disassembling proteins that are not needed ------During a 24-hour period, an adult turns over (makes and degrades) about 250 grams of protein, recycling many of the amino acids. ------If a person's diet is low in protein for a long period, the processes of rebuilding and repairing body proteins will slow down. ---------Over time, skeletal muscles, blood proteins, and vital organs such as the heart and liver will decrease in size or volume. Only the brain resists protein breakdown. Amino Acid metabolism: ---The amino acid pool in a cell can be used to form body proteins, as well as a variety of other possible products. When the carbon skeletons of amino acids are metabolized to produce glucose or fat, ammonia (NH3) is a resulting waste product. The ammonia is converted into urea and excreted in the urine. 1) Amino acids from cell breakdown and amino acids from diet make the amino acid pool in a cell 2) Products: ---synthesis of nonprotein nitrogen-containing compounds, such as serotonin ---fat or ketones made form amino acid carbon skeletons (liver cells only and generally not much) ------yields free ammonia (NH3) ---glucose production from amino acid carbon skeletons (liver and kidney cells only) ------yields free ammonia (NH3) ---synthesis of body proteins for cell structure and other needed components, such as enzymes, hormones, and muscle contractile proteins ---energy production from amino acid carbon skeletons for body cells: yields on average 4 kcal per gram ------yields free ammonia (NH3) 3) free ammonia (NH3) --> urea synthesis in the liver --->excretion of urea by the kidneys

Describe lipid digestion, absorption, and transport in the body. (5, 3 matching) 5.4 Making Lipids Available for Body Use (pp. 176-178) 5.5 Carrying Lipids in the Bloodstream (pp. 179-181)

Digestion (Triglycerides) 1) Stomach: only minor digestion of fat takes place in the stomach through the action of salivary and gastric lipase enzymes ---the stomach (and salivary glands to some extent) secretes the enzyme lipase. ---Salivary lipase and gastric lipase act primarily on triglycerides that have fatty acids with short chain lengths, such as those found in butterfat 2) Liver: the liver produces bile, which is stored in the gallbladder and released through the bile duct into the small intestine. Bile aids in fat digestion and absorption by emulsifying lipids in the digestive juices ---Bile acids (components of bile) act to emulsify fats in the watery digestive juices. ---Emulsification improves digestion and absorption because it separates large fat globules into smaller ones, thereby increasing the total surface area for lipase action ---bile acids get recycled, or absorbed in the last segment of the small intestine and transported back to the liver, after participating in fat digestion 3) Pancreas: the pancreas secretes a mixture of enzymes, including pancreatic lipase, into the small intestine ---Lipase enzyme that is released from the pancreas digests fats in the small intestine. 4) Small intestine: the small intestine is the primary site for digestion and absorption of lipids. Once inside small intestinal cells, long-chain fatty acids are packaged as chylomicrons and transported first through the lymph, then the bloodstream. (shorter-chain fatty acids are absorbed directly into portal circulation) ---Most of the triglycerides in the diet contain fatty acids with longer chain lengths and are generally not digested until they reach the small intestine ---In the small intestine, triglycerides are broken down by lipase into smaller products, namely monoglycerides (glycerol backbones with a single fatty acid attached) and fatty acids. 5) Large intestine: less than 5% of ingested fat is normally excreted in the feces Under the right circumstances, digestion is rapid and thorough--depending on the presence of bile from the gallbladder Phospholipid digestion: is similar to triglyceride digestion. Enzymes from the pancreas and cells in the wall of the small intestine digest phospholipids. ---The eventual products are glycerol, fatty acids, and the remaining phosphorus-containing parts Cholesterol digestion: any cholesterol with a fatty acid attached is broken down to free cholesterol and fatty acids by enzymes released from the pancreas. ---Any fatty acids that are part of these structures could be broken down to yield energy, but contribution to overall calorie intake is minuscule compared to the energy stored in triglycerides. Absorption: ---The products of fat digestion in the small intestine are fatty acids and monoglycerides ---These products diffuse into the absorptive cells of the small intestine---about 95% of dietary fat is absorbed in this way ---The chain length of fatty acids dictates how they will be distributed to the rest of the body. ------If the chain length of a fatty acid is less than 12 carbon atoms, it is relatively soluble in water and small enough to be absorbed into the capillaries and transported via the portal vein directly to the liver. ------Longer chain fatty acids are too large to be absorbed directly into portal circulation. ---------These larger products of fat digestion are reformed into triglycerides within the absorptive cells of the small intestine and eventually enter circulation via the lymphatic system Transport in the bloodstream: ------fat and water do not mix easily---challenge for the transport of fats through the blood and lymph, which are mostly water ---Digestion of dietary fats results in a mixture of glycerol, monoglycerides, and fatty acids. Once these products are absorbed by the cells of the small intestine, they are reassembled into triglycerides... ---Lipoproteins---serve as vehicles for transport of lipids from the small intestine and liver to the body tissues. ------They are found in the bloodstream and contain a core of lipids with a shell composed of protein, phospholipids, and cholesterol ---Chylomicron, VLDL, LDL, and HDL Chylomicron: ---composed of triglyceride ---carries fat from the small intestine to cells ---largest of the lipoproteins, loaded with dietary fat and originate only from the intestinal cells. ---Like the other lipoproteins, chylomicrons are composed of large droplets of lipid surrounded by a thin, water-soluble shell of phospholipids, cholesterol, and protein Process of Chylomicron transport: ---intestinal cells package the triglycerides (from above) into chylomicrons, which enter the lymphatic system and eventually the bloodstream. ---The water-soluble shell around a chylomicron allows the lipid to float freely in the lymph and blood, which are both water based. ---Once a chylomicron enters the bloodstream, the triglycerides in its core are broken down into fatty acids and glycerol by yet another lipase enzyme called lipoprotein lipase, and it is attached to the inside walls of the blood vessels. ---As soon as the fatty acids are released to the bloodstream, they are absorbed by nearby cells. ---The remaining glycerol backbone circulates back to the liver. ---Muscle cells can immediately use the absorbed fatty acids for fuel. ---Adipose cells, on the other hand, tend to reassemble the fatty acids into triglycerides for storage. ---after triglycerides have been removed---The leftover materials are called chylomicron remnants ------Chylomicron remnants are removed from circulation by the liver, and their components are recycled to make other lipoproteins and bile acids. VLDL: ---very-low-density lipoproteins (VLDL) ---Mainly composed of triglyceride (and some cholesterol) surrounded by a water-soluble shell of phospholipids and protein ---VLDLs are rich in triglycerides and thus are very low in density ---carries lipids made and taken up by the liver to cells Process of VLDL transport: ---The liver takes up various lipids from the blood and is the manufacturing site for lipids and cholesterol. ---The raw materials for lipid and cholesterol synthesis include free fatty acids taken up from the bloodstream, as well as carbon and hydrogen derived from carbohydrates, protein, and alcohol. ---The liver then must package the lipids it makes into lipoproteins for transport in the blood to body tissues. ---Once in the bloodstream, lipoprotein lipase on the inner surface of the blood vessels breaks down the triglycerides into fatty acids and glycerol. ---Fatty acids and glycerol are released from the VLDL into the bloodstream and are taken up by the body cells. ---As its triglycerides are released, the VLDL becomes proportionately more dense. ---Much of what eventually remains of the VLDL particle is then called low-density lipoprotein (LDL) LDL: ---low-density lipoprotein (LDL) ---composed of cholesterol ---carries cholesterol made by the liver and from other sources to tissue cells ---"bad" cholesterol---LDL is taken up by receptors on various cells. ------If LDL is not readily cleared from the bloodstream, scavenger cells in the arteries take up the lipoprotein, leading to a buildup of cholesterol in the blood vessels. ------This buildup, known as atherosclerosis, greatly increases the risk for cardiovascular disease. ------Low amounts of LDL are needed as part of routine body functions, but a high level of LDL cholesterol is a risk factor for cardiovascular disease Process of LDL transport: ---LDL particles are taken up from the bloodstream by specific receptors on cells, especially liver cells, and are then broken down. ---The cholesterol and protein components of LDL provide some of the building blocks necessary for cell growth and development, such as synthesis of cell membranes and hormones. HDL: ---high-density lipoproteins (HDL) ---composed of protein ---contributes to cholesterol removal from cells and, in turn, excretion of it from the body ---critical and beneficial participant in this process of lipid transport ---Its high proportion of protein makes it the densest lipoprotein ---"good" cholesterol---amount of HDL in the bloodstream can closely predict the risk for cardiovascular disease. ------Risk increases with low HDL because little cholesterol is transported back to the liver and excreted. ------Women tend to have high amounts of HDL, especially before menopause, compared to men. ------High amounts of HDL slow the development of cardiovascular disease, so any cholesterol carried by HDL can be considered "good" cholesterol Process of HDL transport: ---The liver and intestine produce most of the HDL in the blood ---It roams the bloodstream, picking up cholesterol from dying cells and other sources ---HDL donates the cholesterol primarily to other lipoproteins for transport back to the liver to be excreted. Some HDL travels directly back to the liver. The cholesterol in foods is not designated as "good" or "bad." It is only after cholesterol has been made or processed by the liver that it shows up in the bloodstream as part of LDL or HDL. Dietary patterns can certainly affect the lipoproteins in your blood. The cholesterol in your diet does not have a very big impact on the levels of LDL and HDL in the blood. However, dietary patterns that are low in saturated and trans fats tend to lower total cholesterol, particularly LDL.

Describe the consequences of consuming too much or too little protein. (4) 6.6 Protein Needs, Amino Acid Supplements (pp. 223-224) 6.7 Protein-Calorie Malnutrition (pp. 224-226), Figure 6-16

Our bodies cannot store excess protein once it is consumed, so the excess amino acids are stripped of the nitrogen-containing amino group and may be turned into glucose or ketone bodies and contribute to a positive energy balance, which would be undesirable if weight loss is the goal When only lower-quality protein foods are consumed, the amount of the essential amino acids needed for protein synthesis may not be obtained. -Blood proteins help maintain body fluid balance. With an inadequate consumption of protein, the concentration of proteins in the bloodstream drops below normal. Excessive fluid then builds up in the surrounding tissues because the counteracting force produced by the smaller amount of blood proteins is too weak to pull enough of the fluid back from the tissues into the bloodstream. As fluids accumulate in the tissues, the tissues swell, causing edema. Proteins help regulate acid-base balance in the blood...Proteins located in cell membranes pump chemical ions in and out of cells. The ion concentration that results from the pumping action, among other factors, keeps the blood slightly alkaline. In addition, some blood proteins are especially good buffers in the bloodstream. Buffers are compounds that maintain acid-base conditions within a narrow range. If this doesn't happen, blood acidity issues can happen. Many hormones, our internal body messengers, are proteins and therefore require amino acids for synthesis. Some hormones, such as the thyroid hormones, are made from only one type of amino acid, tyrosine. Insulin, on the other hand, is a hormone composed of 51 amino acids. Almost all enzymes are proteins or have a protein component. Proteins are a key component of cells within the immune system. Antibodies are proteins produced by one type of white blood cell. These antibodies can bind to foreign proteins in the bloodstream—an important step in removing invaders from the body. Without sufficient dietary protein, the immune system lacks the materials needed to function properly. For example, a low-protein status can turn an infection such as measles into a fatal disease for a malnourished child. Protein can form glucose, but only in "starvation mode". If you do not consume enough carbohydrate to supply the glucose, your liver (and kidneys, to a lesser extent) will be forced to make glucose from amino acids present in body tissues Proteins supply little energy for a person at a healthy weight. Two situations in which a person does use protein to meet energy needs are during prolonged exercise and during calorie restriction, as with a weight-loss diet. ---In these cases, the amino group (−NH2) from the amino acid is removed, and the remaining carbon skeleton is metabolized for energy needs. When the carbon skeletons of amino acids are metabolized to produce glucose or fat, ammonia (NH3) is a resulting waste product. The ammonia is converted into urea and excreted in the urine. ---------Under most conditions, cells primarily use fats and carbohydrates for energy needs. Although proteins contain the same amount of calories (on average, 4 kcal per gram) as carbohydrates, proteins are a costly source of calories, considering the amount of processing the liver and kidneys must perform to use this calorie source. Compared to the other macronutrients, proteins provide the highest feeling of satiety after a meal. Meeting protein needs is important, and exceeding needs somewhat may provide an additional benefit when dieting to lose weight Amino acid supplements: ---Because the body's gastrointestinal system is adapted to handle whole proteins as a dietary source of amino acids, individual amino acid supplements can overwhelm the absorptive mechanisms in the small intestine. Amino acid imbalances occur in the intestinal tract because groups of chemically similar amino acids compete for absorption sites in the absorptive cells. For example, an excess of lysine can impair absorption of arginine because they are absorbed by the same transporter. The amino acids methionine, cysteine, and histidine are most likely to cause toxicity when consumed in large amounts. Due to this potential for imbalances and toxicities, the best advice to ensure adequacy is to stick to whole foods as sources of amino acids rather than supplements. Amino acid supplements also have a disagreeable odor and flavor and are much more expensive than food protein. Protein-Calorie malnutrition: ---Protein deficiency is rarely an isolated condition and usually accompanies a deficiency of calories and other nutrients resulting from insufficient food intake. In the developed world, alcoholism can lead to cases of protein deficiency because of the low protein content of alcoholic beverages that make up a high percent of calories. ---Malnutrition can be caused by the illnesses or injuries for which patients are admitted to the hospital and by the hospitalization itself.14 In developing areas of the world, people often have diets low in calories and protein. This state of undernutrition stunts the growth of children and makes them more susceptible to disease throughout life ---People who consume too few of their calories as protein can eventually develop protein-calorie malnutrition (PCM), also referred to as protein-energy malnutrition (PEM) Kwashiorkor: ---When an inadequate intake of nutrients, including protein, is combined with an existing disease, especially an infection, a form of malnutrition called kwashiorkor can develop. ---"the disease that the first child gets when the new child comes." ---Infants in developing areas of the world are usually breastfed from birth. Often by the time the child reaches 1 to 1.5 years of age, the mother is pregnant or has already given birth again, and the newborn infant gets preference for breastfeeding. ---The older child's diet then abruptly changes from nutritious human milk to starchy roots and gruels, which are low in protein compared to their calorie content. ------the foods are usually high in bulky plant fibers, which are very filling and thus prevent the child from consuming enough food to meet calorie needs. Infections also raise calorie and protein needs. ---protein consumption is grossly inadequate ---Famine victims face similar problems. Symptoms: ---Apathy, diarrhea, listlessness, failure to grow and gain weight, and withdrawal from the environment. ------These symptoms complicate other diseases present. For example, a condition such as measles, a disease that normally makes a well-nourished child ill for only a week or so, can become severely debilitating and even fatal. ---Changes in hair color, potassium deficiency, flaky skin, fatty liver, reduced muscle mass, and massive edema in the abdomen and legs. ------The presence of edema in a child who has some subcutaneous fat (i.e., fat directly under the skin) is the hallmark of kwashiorkor ---These children seldom move or cry. When you hold them, you feel the plumpness of edema, not muscle and fat tissue. Symptoms explained with proteins: ---Proteins play important roles in fluid balance, lipoprotein transport, immune function, and production of tissues such as skin, cells lining the GI tract, and hair. ---Children with an insufficient protein intake do not grow or mature normally Recovery: ---If children with kwashiorkor are helped in time—that is, if infections are treated and the dietary pattern becomes plentiful in protein, calories, and other essential nutrients—then the disease process reverses. ---They begin to grow again and may even show no signs of their previous condition, except perhaps shortness of stature. ---Unfortunately, by the time many of these children reach a hospital or care center, they already have severe infections. ---Despite the best care, they still die. Or, if they survive, they return home only to become ill again Marasmus: ---If the nutrient deficiency—especially for calories—becomes severe, a deficiency disease called marasmus can result ---"to waste away," ---referred to as protein-calorie malnutrition, especially when experienced by older children and adults ---typically occurs as an infant slowly starves to death. ---It is caused by diets containing minimal amounts of calories, as well as too little protein and other nutrients. ---commonly develops in infants who either are not breastfed or have stopped breastfeeding in the early months ------When people are poor and sanitation is lacking, bottle feeding often leads to marasmus. ------Often the weaning formula used is improperly prepared because of unsafe water and because the parents cannot afford sufficient infant formula for the child's needs. ------If parents dilute the formula to provide more feedings, they will be providing only more water for the infant. ---Marasmus in infants commonly occurs in the large cities of poverty-stricken countries. Recovery: ---An infant with marasmus requires large amounts of calories and protein, similar to the needs of a preterm infant, and, unless the child receives them, full recovery from the disease may never occur. ---The majority of brain growth occurs between conception and the child's first birthday, with the brain growing at its highest rate after birth. ---If human milk or formula does not support brain growth during the first months of life, the brain may not grow to its full adult size, leading to diminished intellectual function. Both conditions are seen primarily in children but also may develop in adults, even in those hospitalized in North America

Summarize healthy strategies for achieving and maintaining healthy body weight. (7) 7.5 Treatment of Overweight and Obesity (pp. 254-256), Figure 7-18 7.6 Control of Calorie Intake is Essential for Weight Management (pp. 257-260) 7.8 Behavioral Strategies for Weight Management (pp. 262-266), Table 7-6 7.11 Nutrition and Your Health, Popular Diets-Cause for Concern (pp. 273-275)

Treatments require sustainable lifestyle changes, rather than quick fixes promoted by many popular fad diets Losing body fat: Inaccurate 3500-kcal rule---One pound of weight loss includes adipose tissue plus supporting lean tissues and fluids, and represents approximately 3300 kcal per pound (about 7.2 kcal per gram). ------Because there are approximately 3500 kcal in 1 pound of fat, the past 50 years of weight-loss advice has centered on the notion that a deficit of approximately 500 kcal per day is required to lose 1 pound of fat tissue per week. ---the 3500-kcal rule may be an inaccurate predictor of weight change, resulting in unrealistic expectations. ------weight loss occurs more gradually than would be predicted by the 3500-kcal rule because of several factors, including the loss of muscle along with fat during weight loss. Weight change is not linear. ---Rather, it occurs most rapidly during the first year after a change in energy balance and tapers off over the next 2 years. ---In addition, changes in energy intake and physical activity must be strictly maintained over time. ---Research has also shown that individuals have a tendency to overestimate their self-reported physical activity levels and underestimate their dietary intakes What to look for in a sound weight loss plan: Rate of weight loss: ---slow and steady ---no more than 1-2 lbs weight loss per week ---period of weight maintenance for a few months after 10% of body weight is lost ---evaluates need for further weight loss before weight loss begins flexibility: ---supports participation in normal acitivities ---adapts the plan to individual habits/tastes dietary pattern: ---meets nutrient needs with low calorie intake ---includes common foods, with no foods being promoted as magical or special ---uses MyPlate as a pattern for food choices behavior change: ---promotes reasonable, maintainable changes ---encourages social support ---includes plans for relapse, so one doesn't quit after a setback ---promotes changes that control problem eating behaviors ---promotes self-monitoring practices such as keeping food diaries and setting goals overall health: ---requires screening by a physician for people with existing health problems, those over 40 (men) to 50 (women) yrs who plan to increase physical activity substantially, and those who plan to lose weight rapidly ---encourages regular physical activity, sufficient sleep, stress reduction, and other healthy lifestyle changes ---addresses underlying psychological weight issues, ex depression or marital stress Three principles point to importance of preventing obesity: 1) decrease calorie intake by approximately 500 kcal per day to allow for slow and steady weight loss. ---primarily plant-based, high-fiber dietary pattern has proven the most successful in long-term studies ---Portion control---concept of energy density can help dieters choose more nutrient-rich foods with fewer calories per gram ---reading labels---Label reading is critical because many foods are more energy dense than people realize ---write down everything you eat and drink for 24 hours--- then calculate calorie intake by using your diet-analysis software ---control hunger---Eat slowly and stop eating when you are comfortably full. If hunger strikes between meals, determine if you are feeling true hunger; if you are, then choose a small, high-fiber snack to hold you over until the next meal. Drinking a glass of water can also help decrease hunger pangs between meals. Including lean protein (nuts, low-fat dairy, soy protein, or lean meat, fish, or chicken) in meals and snacks will also keep hunger at bay. Eating high-volume foods that are rich in water and fiber will provide bulk with fewer calories, fill your stomach, and send satiety signals to the brain. Becoming aware of what you eat will go a long way to controlling hunger and overall calorie intake. When you slow down, you will not only enjoy each mouthful but also give your stomach time to signal your brain that you are full. ---conquer the weight loss plateau 2) Increase physical activity to the equivalent of more than 150 minutes of moderate-intensity aerobic activity each week. 3) Make positive behavior changes to sustain lifestyle modifications promoting health. ---set realistic goals ---engaging in physical activity 150 minutes per week, drinking plenty of water, or eating five servings of fruits and vegetables a day, rather than reaching for a certain weight ---Making lifestyle changes means identifying the behaviors and barriers that led to weight gain in the first place. ---shifts in dietary patterns--- ------Consume more fruits and vegetables, ------Make half of all grains consumed be whole grains, ------Consume more dairy products in nutrient-dense forms, ------Increase variety in protein food choices and make more nutrient-dense choices, ------Shift from solid fats to oils, Replace high-calorie, high-sodium intakes with more nutrient-dense options: ---------Reduce added sugar consumption to less than 10% of calories per day. ---------Reduce saturated fat intake to less than 10% of calories per day. ---------Reduce sodium intake to less than 2300 milligrams per day. ------Consume no-sugar-added beverages, ------Reduce portion sizes of nonnutrient-dense foods and beverages, ------Meet the physical activity guidelines. ---mindful eating---refers to being consciously aware of the entire eating experience, from food preparation to consumption, including recognizing and respecting everything in between (hunger cues, satiety, flavor, taste, texture, etc.) ---mindless eating---focuses on making the healthier choice the easier choice. ---stimulus control---puts us in charge of temptations: covering tempting food with foil, removing energy-dense snacks from the kitchen counter, and avoiding bringing home especially tempting items. Provide a positive stimulus by keeping healthier snacks available to satisfy hunger and appetite. ---cognitive restructuring---changes our frame of mind: after a hard day, avoid using alcohol or comfort foods as quick relief for stress. Instead, plan for healthful, relaxing activities for stress reduction. Find a positive outlet such as taking a walk or catching up with a good friend. Label some foods as "off limits" or manage with moderation ---contingency management---prepares one for situations that may trigger overeating (e.g., when snacks are served at a party) or hinder physical activity (e.g., rain). ---self-monitoring---can reveal problem eating behaviors—such as unconscious overeating—that may lead to weight gain. Records of dietary and physical activity behaviors can encourage new habits that will counteract unwanted behaviors. ---Overall, it's important to address specific barriers to success such as snacking, compulsive eating, and mealtime overeating. Relapse prevention: ---Successful weight managers plan for lapses, do not overreact, and take charge immediately. Change responses include changing your internal language from "I ate that cookie; I'm a failure" to "I ate that cookie, but I did well to stop after only one!" When individuals lapse from their plan, newly learned food habits should steer them back on track. Without a strong behavioral program for relapse prevention in place, a lapse frequently turns into a relapse and a potential collapse. Maintenance of weight loss is fostered by the 3 Ms: motivation, movement, and monitoring. Social support is important to behavioral change: ---Healthy social support and networking are helpful in weight control. Family and friends can provide praise and encouragement. Unfortunately, your social network can also sabotage your efforts, so be aware of whom you can trust for support. A registered dietitian nutritionist (RDN) or other trained interventionist can keep you accountable and help you navigate difficult situations. Long-term contact with a professional can be helpful for later weight maintenance. Groups of individuals attempting to lose weight or maintain losses can also provide empathetic support. ---Partnerships, programs, and policies that support healthy eating and active living must be coordinated to address obesity epidemic

State the AMDR for protein. Calculate an individual's recommended protein intake (RDA). (3) 6.6 Protein Needs (pp. 220-224)

The RDA for the amount of protein required for nearly all adults to maintain protein equilibrium is 0.8 gram of protein per kilogram of healthy body weight. Requirements are higher during periods of growth, such as pregnancy and infancy, and an increased protein intake of more than 1.0 grams per kilogram of body weight per day has been recommended for older adults Healthy weight is used as a reference in the determination of protein needs because excess fat storage does not contribute much to protein needs Calculating RDA: Calculations using this RDA estimate a requirement of about 56 grams of protein daily for a typical 70-kilogram (154-pound) man and about 46 grams of protein daily for a typical 57-kilogram (125-pound) woman. Convert weight from pounds to kilograms: 154 pounds / (2.2 pounds/kilogram) = 70 kilograms 125 pounds / (2.2 pounds/kilogram) = 57 kilograms Calculate protein RDA: 70 kilograms × (0.8 gram protein) / kilogram body weight = 56 grams 57 kilograms × (0.8 gram protein) / kilogram body weight = 46 grams AMDR-- 10%-35% The RDA for protein translates into about 10% of total calories. Many experts recommend up to 15% of total calories as protein to provide flexibility in diet planning and to allow for the variety of protein-rich foods typically consumed. The Food and Nutrition Board has set an upper range for protein intake at 35% of calories consumed. The Dietary Guidelines encourage the consumption of protein-rich foods such as beans, nuts, seeds, fat-free milk, and seafood.

Identify the recommendations for fat intake from the Food and Nutrition Board (Acceptable Macronutrient Distribution Range) and the American Heart Association. (2) 5.7 Recommendations for Fat Intake (pp. 185-189), Table 5-5

General consensus among nutrition experts is that fat should comprise 20% to 35% of total calories. The Dietary Guidelines for Americans and the Food and Nutrition Board recommend that total fat intake should be 20% to 35% of total calories, which equates to 44 to 78 grams per day for a person who consumes 2000 kcal daily. Linoleic acid: (omega-6) --Men: 17 (3.6 tsp)12 --women: (2.6 tsp) Alpha-linolenic acid: (omega-3) --Men: 1.6 (0.35 tsp) --Women: 1.1 (0.24 tsp) American Heart Association's Diet and Lifestyle Recommendations: ---Use up at least as many calories as you take in ---Eat a variety of nutritious foods from all the food groups, including: ------A variety of fruits and vegetables, Whole grains, Low-fat dairy products ------Skinless poultry and fish ------Nuts and legumes ------Nontropical vegetable oils ---Eat less of the nutrient-poor foods: ------Limit foods and beverages that are high in calories but low in nutrients ------Limit the amount of saturated fat, trans fat, and sodium you eat. ---As you make daily food choices, base your eating pattern on these recommendations: ------Eat a variety of fresh, frozen, and canned fruits and vegetables without high-calorie sauces or added salt and sugars ------Choose fiber-rich whole grains for most grain servings ------Choose poultry and fish without the skin and prepare them in healthy ways ------Eat a variety of fish (especially those rich in omega-3 fatty acids) at least twice a week ------Select fat-free and low-fat dairy products ------Avoid foods containing partially hydrogenated vegetable oils to reduce trans fat in your diet ------Limit saturated fat and trans fat and replace them with monounsaturated and polyunsaturated fats ------If you need to lower blood cholesterol, reduce saturated fats to no more than 5% to 6% of total calories ------Cut back on beverages and foods with added sugars ------Choose foods with less sodium and prepare foods with little or no salt ------If you drink alcohol, drink in moderation (no more than 1 drink per day for women and no more than 2 drinks per day for men) ------Follow the AHA recommendations when you eat out and keep an eye on portion sizes. AHA recommends reducing trans fat and limiting saturated fat to no more than 5% to 6% of total calories to reduce risk for cardiovascular disease

Characterize foods in terms of protein amount and quality identify proteins that are complementary. (4) 6.3 Protein in Foods (pp. 208-213)

The quality of proteins can differ greatly according to their origin (animal or plant), their individual amino acid composition, and their level of amino acid bioactivity. An important part of evaluating protein quality is an accurate measure of the amounts of amino acids absorbed by the body and the contribution of an individual protein source to human amino acid and nitrogen requirements. Animal proteins contain ample amounts of all nine essential amino acids. With a few exceptions such as soy protein and quinoa seed, plant proteins do not match our need for essential amino acids as precisely as animal proteins. ---Many plant proteins, especially those found in grains, are low in one or more of the nine essential amino acids. "High-quality proteins"---those that are readily digestible and contain the essential amino acids in quantities that human require ---humans are able to use proteins from any single animal source more efficiently to support growth and maintenance than from any single plant source. For this reason, animal proteins (except gelatin) are considered high-quality or complete proteins, which contain sufficient amounts of the nine essential amino acids. The majority of individual plant sources of proteins are considered lower-quality (also called incomplete) proteins because their amino acid patterns can be quite different from ours. ---Thus, a single plant protein source, such as corn alone, cannot easily support human growth and maintenance. Only eating lower quality protein foods and the all-or-none principle: ---When only lower-quality protein foods are consumed, the amount of the essential amino acids needed for protein synthesis may not be obtained. ---Therefore, a greater amount of lower-quality protein is needed to meet the demands of protein synthesis, compared to high-quality proteins. ---Once any of the nine essential amino acids in the plant protein we have eaten is used up, further protein synthesis becomes impossible. ---Because the depletion of just one of the essential amino acids prevents protein synthesis, the process illustrates the all-or-none principle: either all essential amino acids are available, or none can be used. The remaining amino acids would then be used for energy needs or converted into carbohydrate or fat. When two or more protein sources are combined in a meal or snack to compensate for deficiencies in their essential amino acid contents, the proteins are called complementary proteins. ---Eating a combination of legumes and grains, such as beans and rice, will supply the body with adequate amounts of all essential amino acids ---vegetables, which are limited in methionine, can be combined with nuts, which are limited in lysine plant combinations: ---grains (missing lysine) + vegetables (missing methionine) or legumes (missing methionine) ---nuts and seeds (missing lysine) + vegetables or legumes ---legumes + nuts and seeds or grains ---vegetables + grains or nuts and seeds Plant proteins: ---plant foods provide more magnesium, fiber, folate, vitamin E, iron (absorption is increased by the vitamin C also present), and zinc than animal sources of protein, and some calcium, and phytochemicals from these foods are implicated in prevention of a wide variety of chronic diseases ---legumes: garden and black-eyed peas, kidney beans, great northern beans, lentils, soybeans, and peanuts ---beans also make an impressive contribution ---nuts include almonds, pistachios, walnuts, and pecans ---Seeds include pumpkin, sesame, and sunflower seeds Animal proteins: ---high diet not recommended ---Eating patterns rich in animal products are most likely low in beneficial substances found in plant sources, including fiber, some vitamins (e.g., folate), some minerals (e.g., magnesium), and phytochemicals, and are high in substances such as saturated fat. ---excessive intake of red meat, especially processed forms, has been linked to cancer