Nutrition Ch 28

Carbohydrates

(CHOs) are the primary energy source for the body. Simple carbohydrates, commonly called sugars, are named according to the number of sugar (or saccharide) units making up their chemical structure. Monosaccharides (simple sugars) consist of a single unit. Disaccharides are molecules made up of two saccharides. Complex carbohydrates consist of long chains of saccharides, called polysaccharides. Dietary fiber, a polysaccharide, is the indigestible "fibrous skeleton" of plant foods. Humans do not have the enzymes to digest fiber; thus, it provides no usable glucose

Incomplete proteins

(e.g., nuts, grains) do not provide all of the essential amino acids. However, by combining two incomplete proteins, a complete protein can be made. For instance, peanut butter on whole-grain bread constitutes a complete protein

Functions of CHOs

1. Supply energy for muscle and organ function. Carbohydrates are more easily and quickly digested than proteins and lipids. They fuel strenuous, short-term skeleton muscle activity and provide nearly all the energy for the brain. Humans store glucose in liver and skeletal muscle tissue as glycogen. Glycogen is converted back into glucose to meet energy needs. This process is called glycogenolysis. 2. Spare protein. If glycogen stores are low (e.g., in an undernourished person), physical activity causes the body to catabolize stores of protein (gluconeogenesis) and lipids (fats) to use for energy. However, when proteins are used for energy, they are not available for their primary functions of tissue growth, maintenance, and repair. Fats are then converted directly into an alternative fuel called ketones, which raise the acidity of the blood and can lead to acid-base imbalance. 3. Other physiological functions included the following; Increase satiety (feeling of fullness and satisfaction). Improve absorption of sodium and excretion of calcium. Enhance insulin secretion. Insulin is a pancreatic hormone that promotes the movement of glucose into the cells for use.

Essential and Nonessential Fatty Acids

A fatty acid is considered essential if (1) the body cannot manufacture it and (2) its absence creates a deficiency disease. The essential fatty acids, linoleic acid (omega-6) and alpha-linolenic acid (omega-3), help protect against heart disease

How Do I Calculate a Client's Total Energy Needs?

A person's total daily energy requirement is the number of kcal necessary to replace those used for basic metabolism plus those used in physical activities. The following are simple, general estimates based on activity level and age: Sedentary women and older adults need 1,600 kcal/day. Children, teenage girls, active women, and most men need 2,200 kcal/day. Teenage boys, active men, and very active women need 2,800 kcal/day. To calculate energy use more precisely, you need to know the person's age, weight, and physical activity, including the intensity and duration of the activity (Table 28-5). Heightened emotional states may also increase energy needs because they increase muscular activity in the form of muscle tension, restlessness, and agitated movements.

Glycerides

Also called true fats, glycerides consist of one molecule of glycerol attached to one, two, or three fatty acid chains. Glycerol is an alcohol composed of three carbon atoms. Fatty acids are long chains of carbon and hydrogen atoms ending in an acid. Triglycerides are the main glycerides found in foods. They are compounds consisting of a glycerol molecule attached to three fatty acids

Traditional Asian, Latin American, Mediterranean, and African heritage and vegetarian/vegan diets

Although recipes are seasoned with culturally specific ingredients, these different diets similarly emphasize eating fresh local and seasonal foods. This back-to-earth style of eating is typically home-cooked and avoids excess sugar, salt, and solid fats. For healthy living, portion sizes are moderate (Oldways, n.d). You can find specific diets at the Oldways Preservation and Exchange Trust Web site.

Proteins

Complete proteins come mostly from animal sources: meat, poultry, fish, eggs, and milk products. Incomplete proteins are supplied by plant sources (e.g., grains, nuts, legumes, seeds, vegetables). They can be combined to make complete proteins. Stomach: Pepsin Pancreas: Trypsin, chymotrypsin, carboxypeptidase Intestine: Aminopeptidase, dipeptidase 10%-35% of the adult diet should be calories from protein, or 0.8 g/kg of body weight (46-56 g/day for an "average" person). Protein needs depend on age, body size, and physical state. Needs are increased during growth periods such as childhood and pregnancy.

Functions of Protein

Dietary proteins perform the following functions: Tissue building. Protein is essential for growth, maintenance, and repair of body cells and tissues. Except for water, protein makes up the biggest portion of the body. Metabolism. Enzymes facilitate cellular reactions throughout the body. Proteins are precursors to digestive enzymes and hormones (e.g., thyroxine). In addition, proteins combine with iron to form hemoglobin, the oxygen carrier in red blood cells. Immune system function. Lymphocytes (specialized white blood cells [WBCs]) and antibodies (components of our immune system that defend against foreign invaders) are proteins. Fluid balance. Because they attract water, proteins in cells and the bloodstream help regulate fluid balance. Acid-base balance. Blood proteins function as buffers, helping to regulate acid-base balance. Secondary energy source. As noted earlier, proteins can be broken down to provide energy when stores of the fats and CHOs are inadequate (Thompson & Manore, 2014). Lean meat is nourishing and healthy as long as it is consumed in modest amounts, is low in saturated fat, and is not processed. Many North Americans eat more protein than they need, especially in the form of red meat. Animal proteins high in saturated fat increase the risk for certain cancers and coronary artery disease.

Saturated and Unsaturated Fatty Acids

Fatty acids are classified as saturated, unsaturated, or trans-fats (Table 28-2). Saturation means that a substance is holding all that it is capable of holding. An unsaturated fatty acid is not filled with all the hydrogen it can hold. Therefore, it is lighter and less dense Monounsaturated fat molecules have one unfilled spot where hydrogen is not attached. Polyunsaturated fatty acids contain two or more unfilled spots for hydrogen. At the spot(s) where no hydrogen is attached, the molecule becomes kinked and does not pack together. This is why these fats are liquid at room temperature. Dietary fat should mainly be polyunsaturated and unsaturated, to reduce the risk of heart disease and stroke. Saturated fatty acids are those in which every carbon atom is fully bound to (or "saturated" with) hydrogen. The molecules pack tightly together at room temperature and are dense, solid, and heavy.

Balanced Eating Pattern

Limit fats: Total fat intake—below 20% to 35% of total calories Saturated fats—less than 10% of total calories Trans-fats—less than 1% of calories Cholesterol—less than 300 mg Sources—Most fats should come from foods such as fish, nuts, and vegetable oils. Include fat-free or low-fat dairy, including yogurt, milk, and cheese. Avoid processed cheese products and dairy with added sugars. Choose a variety of, preferably fresh, fruits and vegetables each day—at least 2½ cups of dark green, red, and orange vegetables and legumes (beans and peas). Choose whole grains often. At least half of complex carbohydrates should come from whole grains. Choose nutrient-dense food and beverages in appropriate portions, avoiding those with empty calories and excessive sugar and caffeine. Taking in the right amount of calories for you (one size does not fit all) based on age, sex, height, weight, and physical activity level. Be physically active each day. Balance calorie intake based on activity level. Engage in a minimum of 300 min/week of moderate intensity physical activity (U.S. Department of Health and Human Services, 2008). Avoiding The "Bad Stuff." Limit salt to less than 1,500 mg per day for all African Americans and those with hypertension, diabetes, and chronic kidney disease (including children), as well as persons older than 50. For everyone else, 2,300 mg is the recommended daily limit. Alcohol only in moderation—Up to one drink per day for women, and two per day for men. Practice food safety by preparing, cooking, chilling, and storing foods to keep them free from harmful microorganisms. Also clean hands, food contact surfaces, and fruits and vegetables. Do not wash or rinse meat and poultry.

Lipids

Lipids are organic (carbon-containing) substances that are insoluble in water. They are made up of carbon, hydrogen, and oxygen—the same basic elements that make up carbohydrates. Fats are solid at room temperature. Oils are liquid at room temperature. For example, butter is a fat even when it is melted, because it would be solid at room temperature. You will hear the terms lipids and fats used interchangeably. Fat is an essential nutrient for brain and nerve function, but certain types, when consumed in excess, can also be a health hazard. Lipid metabolism occurs in the small intestine. Because lipids are insoluble in water and because blood is primarily water, lipid absorption requires a solvent carrier

Functions of Lipids

Lipids perform the following functions: 1. Supply essential nutrients. Food fats supply the essential fatty acids and aid in the absorption of fat-soluble vitamins. 2. Energy source. The body burns fat for energy when engaging in sustained light activity, when glycogen stores are exhausted, and when at rest. During strenuous physical activity, carbohydrates are the primary energy source. 3. Flavor and satiety. Lipids give food its creamy taste and texture and promote satiety (the feeling of being "full"). Fats are digested more slowly than carbohydrates, so stomach emptying time slows. 4. Other functions. Body fat provides insulation, protects vital organs, aids in thermoregulation, and enables accurate nerveimpulse transmission. In addition, lipids are a component of every cell membrane and are essential to cell metabolism. 5. Cholesterol functions. Cholesterol is a component of every cell in the body, where it lends suppleness and support. It is also an ingredient of bile, which helps digest fats, and serves as a precursor to all steroid hormones, including sex hormones. When lipid metabolism is "disordered," cholesterol contributes to atherosclerosis.

Dietary Fats

Monounsaturated Olives; olive oil, canola oil, and peanut oil; cashews, almonds, peanuts, and most other nuts; avocados Lowers LDL and raises HDL. Polyunsaturated Corn, soybean, safflower, sesame, sunflower, and cottonseed oils; fish, nuts, and seeds Lowers LDL and raises HDL. Saturated Whole milk, butter, cheese, and ice cream; red meat; chocolate; coconuts, coconut milk, and coconut oil; palm oils; cocoa butter; processed foods Raises LDL and HDL. Trans-fats Most margarines; vegetable shortening; partially hydrogenated vegetable oil; deep-fried chips; many fast foods (e.g., French fries, donuts); most commercial baked goods Raises LDL. Dietary Cholesterol Foods from animals: meats, egg yolks, dairy products, organ meats (e.g., heart, liver), fish, and poultry Raises cholesterol.

Lipids

Saturated fats occur in pork, beef, poultry, seafood, egg yolk, and dairy; coconut oil and palm oil. Unsaturated fats (from plants) occur in olives, olive oil, vegetable oils (peanut, soybean, cottonseed, corn, safflower), nuts, and avocados. Essential fatty acids (linoleic acid [omega-6] and alpha-linolenic acid [omega-3]) occur in polyunsaturated vegetable oils and in fatty fish (e.g., salmon). Trans-fats occur in hydrogenated oils, some margarines, packaged baked goods, and many processed foods. Lingual: Lipase Gastric: Lipase, tributyrinase, bile salts Pancreatic lipase (steapsin) Healthy adults should get 20%-35% of their calories from fat; children, 25%-40%. The American Heart Association recommends that people obtain < 30% of their calories from fat; < 7% of calories should come from saturated fats and < 1% from trans-fat. People with increased risk for heart disease may need stricter control.

Carbohydrates

Simple sugars occur mainly in corn syrup, honey, milk, table sugar, molasses, sugar cane, sugar beets, and fruits. Complex carbohydrates occur in vegetables, breads, cereals, pasta, grains, and legumes. Salivary amylase (mouth) Ptyalin (mouth and stomach) Pancreatic amylopsin Intestinal: Sucrase, lactase, maltase DRI requirements for healthy adults are 45%-65% of calories from CHOs, or 130 grams per day (g/day). Body size and activity level affect the amount of carbohydrate used by the body. There is debate about the amount of dietary carbohydrate needed. Many popular diet plans alter carbohydrate intake. Some focus on low carbohydrate intake; others recommend a high intake of complex CHOs

Diabetes Food Plate

The American Diabetes Association offers an online interactive tool called Create Your Plate to help diabetics manage blood glucose and lose weight. The diabetes food plate emphasizes a diet higher in nonstarchy carbohydrates and proteins

Water-Soluble Vitamins

The water-soluble vitamins include vitamin C and the B-complex vitamins (Table 28-3). Because these vitamins are soluble in water, excess amounts are regularly excreted in the urine. Thus: Toxicity is rare except in people with renal disease. The body cannot store these vitamins, so they need to be consumed every day

MyPlate for Older Adults

This visual good guide illustrates healthy food choices and portions specific for the nutrition and hydration needs of older adults. It is consistent with the Dietary Guidelines for Americans 2015-2020. Both recommend limiting foods high in trans- and saturated fats, salt, and added sugars; and emphasize whole grains. It also stresses the importance of fluids and promotes physical activity. To see MyPlate for Older Adults,

MICRONUTRIENTS

Vitamins and minerals are called micronutrients because they are required by the body in only very small amounts. Although they provide no energy, they are critical in regulating a variety of body functions

What Are Some Body Weight Standards?

Weight standards have been established to correlate weight with good health and longevity and to help determine a client's ideal body weight. The general ideal weight guide uses a formula to determine a reasonable weight based on height: Men: 106 lb (47.7 kg) for the first 5 ft (150 cm), then add 6 lb/in. (2.7 kg/2.5 cm) Women: 100 lb (45 kg) for the first 5 ft (150 cm), then add 5 lb/in. (2.25 kg/2.5 cm) Add 10% for large body frame; subtract 10% for small body frame. Various height and weight tables have been developed over the years. World Health Organization (WHO) child growth standards are based on statistical estimates and often include variations for age, sex, and body frame. Type who.int/childgrowth into your browser and follow the links if you want to see the World Health Organization (WHO) child growth standards. Body composition analysis attempts to quantify lean body mass versus percentage body fat. Lean body mass includes muscle, bone, and connective tissue. Lean tissue weighs more than fat; thus, a person who engages in regular weight-bearing exercise and is physically fit may actually weigh more than an individual of similar appearance who is sedentary and unfit. Various methods to assess body composition, known as anthropometric measurements, are provided in the Assessment section later in the chapter.

Nitrogen Balance

When amino acids are catabolized, the nitrogen-containing part is converted to ammonia and excreted in the urine as urea. Therefore, nitrogen level reflects how well body tissues are being maintained. Nitrogen balance occurs when intake and output of nitrogen are equal. Positive nitrogen balance exists when nitrogen intake exceeds output, making a pool of amino acids available for growth, pregnancy, and tissue maintenance and repair. Negative nitrogen balance exists when nitrogen loss exceeds nitrogen intake. This occurs in illness, injury (e.g., burns), and malnutrition

What Factors Affect Basal Metabolic Rate?

When interpreting test results, consider the following factors that influence BMR: Body composition. Lean body tissue has greater metabolic activity than fat and bones. This explains why women, who have on average more adipose tissue than men, also have lower BMRs. Growth periods. BMR increases during periods of growth, such as the first 5 years of life, adolescence, pregnancy, and lactation. Body temperature. The BMR increases 7% for each 1°F (0.83°C) rise in body temperature. Environmental temperature. Cold weather, especially temperatures below freezing, causes a slight rise in the BMR to generate body heat and maintain normal body temperature. Disease processes. Diseases and injuries involving increased cellular activity result in BMR elevation (e.g., cancer, anemia, cardiac failure, hypertension, asthma, severe burns, traumatic injury). Prolonged physical exertion. Examples: chopping wood, running.

Phospholipids

a key component of lipoproteins, which consist of phospholipids and a protein. Because they are water soluble, lipoproteins are the major transport vehicles for lipids in the bloodstream. By "wrapping" triglycerides with water-soluble phosphates and proteins, lipoproteins deliver these substances to body cells. Low-density lipoproteins (LDLs) transport cholesterol to body cells. Diets high in saturated fats increase LDLs circulating in the bloodstream and may result in fatty deposits on vessel walls, causing cardiovascular disease. As a result, LDL is often known as the "bad cholesterol." High-density lipoproteins (HDLs) remove cholesterol from the bloodstream, returning it to the liver, where it is used to produce bile. Thus, a high blood level of HDL is considered protective against cardiovascular disease. It is often known as the "good cholesterol."

basal metabolic rate

a measure of the energy used while at rest in a neutral temperature environment—the energy required for vital organs such as the heart, liver, and brain to function

Standards

a reference for nutrient intake thought to meet the nutritional needs of most healthy population groups. They list nutrient amounts in measurements, such as grams and milligrams, and are not intended to indicate individual requirements or therapeutic needs

Essential amino acids

are significant in our diets because the body cannot manufacture them. They must be supplied by food or nutritional supplements. Examples: Arginine, histidine, isoleucine, leucine, lysine, methoionine, phenylalanine, threonine, tryptophan, and valine Some consider arginine to be nonessential because it cannot be synthesized at a rate that will support growth; it is essential for children, but not for adults

Nonessential amino acids

can be synthesized in the body, so we do not need to obtain them from food. Examples: Alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine Cysteine is considered essential in some situations, such as in immaturity or severe stress. For protein synthesis to occur, every amino acid necessary to build that protein must be available

Proteins

complex molecules made up of amino acids. Every amino acid consists of a central carbon atom connected to a hydrogen atom, an acid, an amine (a region of the molecule containing nitrogen), and a side chain. Just 20 different amino acids are the building blocks of most of the proteins in the human body

Complete proteins

contain all of the essential amino acids necessary for protein synthesis. These usually come from animal sources

energy

energy balance, macronutrients, micronutrients, and factors that influence nutritional status.

Fat-Soluble Vitamins

fat-soluble vitamins are A, D, E, and K. They are stored primarily in the liver and adipose tissues, although vitamin E is deposited in all body tissue. Stored in the body. Because the body can store these vitamins, we do not need to consume them every day if we are consuming them in adequate amounts. However, diets extremely low in fat and disorders affecting fat digestion and absorption can lead to deficiency of fat-soluble vitamins. Not readily excreted. Because they are not readily excreted, excessive supplementation with the fat-soluble vitamins can lead to toxicity. Some need more vitamin D. The Institute of Medicine and other guidelines recommend that those with little sun exposure, oseteoporosis, dark skin, or taking medication interfering with vitamin D absorption may require more than the daily recommendation

Micronutrients

help manufacture, repair, and maintain cells

Minerals

inorganic elements found in nature. They occur in naturally in foods, as food additives, and in supplements. Major minerals (macrominerals) are minerals that the body needs in amounts of 100 mg/day or greater. Trace minerals are essential, but in a lower concentration. Functions Minerals assist in fluid regulation, nerve impulse transmission, and energy production; they are essential to the health of bones and blood and help rid the body of by-products of metabolism. Evidence also shows that minerals play key roles in disease prevention and treatment. For example: 1. Adequate calcium intake throughout the life span decreases the likelihood of osteoporosis (a condition marked by porous bones). The recommended daily intake is difficult to achieve by diet alone. In the United States, calcium deficiency is one of the most common mineral deficiencies (Table 28-4). 2. Iron deficiency causes anemia, the most common nutritional problem worldwide. 3. Magnesium deficiency increases the risk of hypertension and coronary artery disease in women. 4. Sodium, consumed in high amounts (> 2,500 mg/day), increases the risk for high blood pressure, heart attacks, and stroke. If the body is deficient in a mineral, it absorbs more; if the body has enough, it absorbs less and excretes more in the feces. Minerals interact with other minerals, vitamins, and other substances to accomplish absorption and metabolism and perform their functions. For example, iron absorption is enhanced in the presence of vitamin C, and vitamin D deficiency inhibits calcium absorption.

Catabolism

involves the breakdown of larger molecules into smaller components. This process releases energy

Anabolism

involves the formation of larger molecules from smaller ones. For example, if protein is needed for tissue repair, amino acids are recombined to form proteins. This process requires energy

Sterols

lipids, but are not made of fatty acids. The most important sterol in the body is cholesterol, a wax-like substance needed for the formation of cell membranes, vitamin D, estrogen, and testosterone. Cholesterol is synthesized in the liver, and it is also found in animal food

Water

made up of hydrogen and oxygen and makes up about half of total body weight (55% to 65% in men and 50% to 55% in women). This is because men have greater muscle mass, and muscle contains a relatively large amount of water. Water is distributed in two body compartments Intracellular fluid is the water contained within each living cell. It makes up about 40% of the total body weight. Extracellular fluid is external to the cell membrane (e.g., in the fluid portion of blood and lymph and in the gastrointestinal [GI] tract); it accounts for 20% of body weight. Water is critical to the body because its functions are essential to life: Solvent. Water is the basic solvent for the body's chemical processes. Transport. As a component of blood, water serves as a medium for transporting oxygen, nutrients, and metabolic wastes. Body structure and form. Water "fills in the spaces" in body tissues (e.g., in blood, lymphatic material, and muscle) and by way of diffusion and osmosis transports ions into and out of cells. Temperature. Water helps maintain body temperature. When body temperature rises, evaporation of sweat helps cool the body. Lubricant. Fluid reduces friction between moving surfaces, such as in joints, and in thoracic and abdominal cavities where organs need to move freely. Catalyst. Water is a part of many biochemical reactions, such as the conversion of carbohydrates and proteins into energy during the digestive process. The amount of water a person requires varies according to the environmental humidity and temperature, activity level, age, and metabolic needs. The average AI is about 2.7 liters of water per day for adult women and 3.7 liters for men (Lutz, Mazur, & Litch, 2015; Sawka, Cheuvront, & Carter, 2005). Eighty percent of those amounts should come from fluids. We also obtain water in the foods we eat. Overall fluid balance is maintained when fluid intake (in liquids, foods, and metabolic reactions) matches fluid output (through urine, feces, respiration, and sweat.) Fluid and electrolyte balance is discussed in

Food Guides

more practical tools that you can use to educate patients and families. They specify the number of servings of foods needed daily so nonprofessionals can use them in making healthful meal choices.

Vitamins

organic substances that are necessary for metabolism or preventing a particular deficiency disease. They are critical in building and maintaining body tissues, supporting the immune system to fight disease, and ensure healthy vision. Vitamins are especially critical during periods of rapid growth, pregnancy, lactation, and healing. Because the body cannot make vitamins, they must be supplied in food or supplements

Direct measurement of BMR

requires use of a calorimeter: an insulated unit that measures temperature changes of water that are produced by exposure to a fasting individual at rest. Although it is very accurate, it is rarely used because most institutions do not have calorimeters and because the test requires a controlled environment and a 12-hour fast. Direct measurement of BMR is used primarily by researchers

Trans-fatty acids

saturated fats created when food manufacturers add hydrogen to polyunsaturated plant oils, such as corn oil, to break the double carbon bonds and straighten out the molecules. This process solidifies the fat and extends the shelf life of the food. Trans-fats are found in processed foods containing hydrogenated vegetable oils. Saturated fats and trans-fats are the main dietary factors in increasing blood cholesterol levels. They raise LDL cholesterol levels. The FDA mandates that trans-fat content be listed on all food labels.

Indirect calculation of BMR

sometimes called the resting energy expenditure, includes the following: Measuring oxygen uptake per unit of time. This can be done in an exercise lab or with portable machines at the bedside. It is most often done for patients in intensive care units. Not all facilities have this capability. Serum thyroxine levels (a blood test). A formula for calculating BMR when precise measurement is not required

Macronutrients

supply the body with energy (kilocalories). Table 28-1 lists the sources of and requirements for macronutrients

Nutrition Facts label

the U.S. Food and Drug Administration (USFDA) requires this label on all packaged foods sold in the United States. The Nutrition Facts panel contains important information about serving size, number of servings per package, total calories and calories from fat per serving, a list and amounts of the key nutrients in the food, and the percent daily values (% DV) for the nutrients listed on the panel. The % DV identifies the percentage that a serving of the food contributes to a consumer's daily intake of the nutrient listed. Teaching your patients how to use these labels will help them to make wiser dietary choices

Adequate Intake (AI)

the amount of a nutrient consumed by a group of healthy people.

Estimated Average Requirement (EAR)

the amount of a nutrient that is estimated to meet the requirement of half of all healthy individuals within a given age and gender group

Recommended Dietary Allowance (RDA)

the average daily dietary intake of a nutrient that is sufficient to meet the nutritional requirements of approximately 98% of healthy people.

metabolism

the body converts food into complex forms of chemical energy and then into usable energy, which is then carried to individual cells. Metabolism encompasses all the ways in which the body changes and uses nutrients for vital processes and bodily functions. Most metabolic reactions are triggered by enzymes; each is specific and catalyzes only one type of reaction. Two types of metabolic reaction, anabolism and catabolism, occur continually and are adjusted according to the needs of the body

Tolerable Upper Intake Level (UL)

the maximum daily intake of a nutrient that is likely to be without adverse health effects for almost all individuals.

Acceptable Macronutrient Distribution Range (AMDR)

the percentage of protein, fat, and carbohydrate associated with reduced risk of chronic disease, provided there is an intake of other essential nutrients

Metabolism

the process by which the body converts food into energy. Good nutrition is essential to wellness, and poor nutrition contributes to disease; so clients need accurate, current, and appropriate nutritional information. Before you can give effective individualized advice, you need to know about the nutrients found in foods

Nutrition

the study of food: how it affects the human body and influences health.