BIOL 1215 Principles of Nutrition CH 7-9

Describe major functions of each fat-soluble vitamin: Focus on A, D, E, K

A -Normal vision and reproduction, cellular growth, and immune system function D -Absorption of calcium and phosphorus, maintenance of normal blood calcium, calcification of bone, maintenance of immune function E -Antioxidant, maintenance of nervous and immune system functions K -Production of active blood-clotting factors

List the four fat-soluble vitamins, and identify good food sources of each fat-soluble vitamin (or provitamin): Focus on A, D, E, K

A -Preformed: liver, milk, fortified cereals Provitamin: yellow-orange, red, and dark green fruits and vegetables D -Vitamin D-fortified milk, fortified cereals, fish liver oils, fatty fish E -Vegetable oils and products made from these oils, certain fruits and vegetables, nuts and seeds, fortified cereals K -Green leafy vegetables, canola and soybean oils, and products made from these oils

Explain the difference between a high-quality protein and a low-quality protein.

A high-quality (complete) protein contains all essential amino acids in amounts that support protein deposition in muscles and other tissues, as well as a young child's growth. High-quality proteins are well digested and absorbed by the body. A low-quality (incomplete) protein lacks one or more of the essential amino acids or contains inadequate amounts of these nutrients. Furthermore, the human digestive tract does not digest low-quality protein sources as efficiently as foods containing high-quality protein. The essential amino acids that are in relatively low amounts are referred to as limiting amino acids because they reduce the protein's ability to support growth, repair, and maintenance of tissues. In most instances, lysine, tryptophan, threonine, and the sulfur-containing amino acids methionine and cysteine are the limiting amino acids in foods

Identify food groups that contribute most of the protein in the typical American diet.

According to results of recent research, plant-based proteins, including proteins from grains, beans, legumes, peas, and nuts, supply only 20 to 30% of Americans' protein intake. Meat, fish, poultry, dairy, and eggs provide most of the protein (70-85%) in the diet In 2015-2016, unprocessed poultry (especially chicken and turkey) contributed the largest share of adult Americans' total protein intake from meat

Identify some practical steps that people can take to reduce their risk of cancer.

At this point, the best course of action is to take steps to prevent cancer. According to the American Cancer Society, people can change their diets to reduce their risk of cancer by: limiting alcohol consumption; achieving and maintaining a healthy weight; adopting a physically active lifestyle; and eating a healthy diet that limits intakes of red and processed meat and emphasizes intakes of plant foods, including fruits, vegetables, and whole grains Avoiding obesity by establishing healthy eating and physical activity habits, especially early in life, may reduce the risk of cancer. According to results of epidemiological studies, people who exercise regularly have lower risks of certain cancers, including colon and breast cancer. Regular physical activity may reduce the risk by helping to control weight, improving immune system functioning, and enhancing the body's regulation of various hormones.

Discuss the pros and cons of drinking bottled water.

Bottled water is sealed in containers and has no added ingredients other than a substance that prevents the growth of microbes, such as bacteria. Bottled water may have fluoride added, but amounts must meet FDA guidelines. If bottled water manufacturers add flavorings or other ingredients to their products, the name of the product must indicate the added ingredients; "Bottled Water with Cherry Flavor," for example. These drinks are often called "flavored water beverages." Flavored waters may simply contain additives that make the beverage taste good, but a growing number of flavored waters also have added nutrients other than sugars, such as sodium, potassium, and amino acids. The beverage's label must identify the additives in the list of ingredients. Safety standards for bottled water are similar to those established by the EPA for tap water. According to FDA guidelines, bottled water manufacturers are responsible for producing safe products. Production procedures for bottled water must follow manufacturing regulations established and enforced by the FDA. Additionally, the FDA inspects water bottling facilities regularly. Because of FDA regulations and oversight, consumers can be assured that their supply of bottled water is safe. Additionally, most Americans can trust the safety of their tap water because the vast majority of municipal water systems in the United States are regulated by the Safe Drinking Water Act (SDWA). As a result of this law, most tap water undergoes a thorough purification process and is constantly tested for safety. If such testing indicates that the water supply may pose a threat to public health, consumers are warned through media, and a "boil order"—requirement to boil water for 10 minutes to kill harmful microorganisms—may be issued. Although bottled water is safe to drink, the plastic used to contain it may have toxic effects on health. Bisphenol (biss′-feen-ol) A, which is also called BPA, is a chemical used to make polycarbonate plastics and epoxy resins. Polycarbonate plastics are in many consumer products that come in contact with foods and beverages, including some water bottles and older baby bottles. The epoxy resin that contains BPA is used to coat the inside of certain food cans. The coating prevents the can's metal from coming in contact with and being damaged by the food (Fig. 9.25). However, BPA can leach from polycarbonate plastic containers or epoxy resin-coated cans and enter the food or beverage stored within them. Scientists are studying BPA to determine the extent to which the chemical can affect human health. Concern over the safety of BPA has encouraged some manufacturers to discontinue using the chemical in their products. Plastic containers that are marked with recycle codes 1, 2, 4, 5, and 6 most likely do not contain BPA. Some plastics that are marked with recycle codes 3 or 7 may be made with BPA (Fig. 9.26).43 To reduce exposure to BPA, consider taking these actions: Avoid heating foods in polycarbonate plastic containers. Avoid plastic containers that have the symbol shown in Figure 9.26. Do not wash polycarbonate containers in the dishwasher or with harsh detergents. Reduce intake of foods in cans lined with epoxy resins. Cook or store foods and beverages in glass, porcelain, or stainless steel containers. Avoid using polycarbonate dishware, cups, or eating utensils for serving foods (especially hot foods or liquids). Use baby bottles and drinking cups that are BPA free; avoid using old plastic baby bottles and toys that may contain BPA.

Describe deficiency and toxicity disorders associated with major minerals: focus on calcium, sodium, potassium, magnesium.

Ca -Increased risk of osteoporosis May increase risk of hypertension -Upper Level (UL) = 2.0-2.5 g/day Intakes > 2.5 g/day may cause kidney stones and interfere with absorption of other minerals. Na -Muscle cramps -UL = 2300 mg/day Contributes to hypertension in susceptible individuals Increases urinary calcium losses K -Irregular heartbeat Muscle cramps -No UL has been determined. Slowing of heart rate that can result in death Mg -Muscle weakness and pain Poor heart function -UL = 350 mg/day (medication-related) Diarrhea

List key functions and good food sources of the major mineral nutrients: focus on calcium, sodium, potassium, magnesium.

Ca -Structural component of bones and teeth Blood clotting Transmission of nerve impulses Muscle contraction Regulation of metabolism -Milk and milk products, canned fish, tofu made with calcium sulfate, leafy vegetables, calcium-fortified foods such as orange juice Na -Maintenance of proper fluid balance Transmission of nerve impulses Muscle contraction Transport of certain substances into cells -Luncheon meats; processed and canned foods; pretzels, chips, and other snack foods; condiments; sauces; table salt Mg -Bone strengthening Serves as a cofactor for certain enzymes Maintains normal heart and nerve functioning -Wheat bran, green vegetables, nuts, chocolate, legumes K -Maintenance of proper fluid balance Transmission of nerve impulses -Fruits, vegetables, milk, meat, legumes, whole grains

Describe ways to conserve the vitamin context of foods or increase vitamin bioavailability: fat soluble and water soluble vitamins, fruits and vegetables.

Fat-soluble vitamins are chemically similar to lipids, and the vitamins are in fatty portions of food. Thus, processes that normally occur during fat digestion facilitate the absorption of fat-soluble vitamins. For example, bile enhances lipid, as well as fat-soluble vitamin absorption. In the small intestine, the presence of fat stimulates the secretion of a hormone that causes the gallbladder to release bile. Therefore, adding a small amount of fat to low-fat foods, such as tossing raw vegetables with some salad dressing, adding a pat of soft margarine to steamed carrots, or stir-frying green beans in peanut oil, can enhance the intestinal tract's ability to absorb the fat-soluble vitamins in these foods. A diet that contains adequate amounts of a wide variety of foods, including minimally processed fruits, vegetables, and whole-grain breads and cereals, can help supply the vitamin needs of most healthy people. Vitamin deficiency disorders generally result from inadequate diets or conditions that increase the body's requirements for vitamins, such as reduced intestinal absorption or higher-than-normal excretion of the micronutrients. Today, severe vitamin deficiencies are uncommon in the United States, thanks in part to modern food preservation practices, food enrichment and fortification, and the year-round, widespread availability of fresh fruits and vegetables from other countries. Many Americans, however, consume considerably less than recommended amounts of certain vitamins, particularly vitamins E, D, and the vitamin-like compound choline In many instances, unpackaged ("bulk") fresh fruits or vegetables that are sold in supermarkets do not have dates indicating when they should be used, and consumers have no way of knowing when the produce was harvested. Avoid produce that is bruised, wilted, or shriveled, or shows signs of decay such as mold Some vitamins, such as niacin and D, resist destruction by usual food storage conditions or preparation methods. Other vitamins—particularly vitamin C, thiamin, and folate—are easily destroyed or lost by improper food storage and cooking methods. Fresh produce is more likely to retain its natural vitamin content when stored at temperatures near freezing, in high humidity, and away from air. Therefore, you should keep most fresh fruits and vegetables in plastic packaging and chilled until you are ready to use them. Exposure to excessive heat, alkaline substances, light, and air can destroy certain vitamins, especially vitamin C. To reduce such losses, trim, peel, and cut raw fruits and vegetables just before eating or serving them. Water-soluble vitamins can leach out of food and dissolve in the cooking water, which is often discarded. By cooking vegetables in small amounts of water and reusing that water for soups or sauces, you are likely to consume those water-soluble nutrients. Quick cooking methods that involve little contact between produce and water, such as microwaving, steaming, and stir-frying, can conserve much of the vitamin content of the food

Describe hypertension and osteoporosis, including risk factors. Know normal vs. high blood pressure reading.

Hypertension -Hypertension, a condition characterized by persistently elevated blood pressure, is a serious public health problem in the United States. Compared to people with normal blood pressure, hypertensive individuals have greater risk of CVD, especially heart disease and stroke, as well as kidney failure and damage to other organs. Approximately one-third of adult Americans have hypertension.20 Children can also develop hypertension. In the United States, one in nine children has chronically elevated blood pressure levels.17 Hypertension is often called the "silent killer" because high blood pressure generally does not cause symptoms until the affected person's organs and blood vessels have been damaged. -The best way to detect hypertension is to have regular blood pressure screenings. When you have your blood pressure determined, two measurements are actually taken. The first measurement is the systolic pressure, which is the maximum blood pressure within an artery. This value occurs when the ventricles, the heart's pumping chambers, contract. The second measurement is the diastolic pressure, which measures the pressure in an artery when the ventricles relax between contractions. The systolic value is always higher than the diastolic value. For adults, healthy blood pressure readings are less than 120/80 millimeters of mercury (mm Hg). After having your blood pressure measured, ask the clinician for your systolic and diastolic readings and keep a record of the values. -A person who is under physical or emotional stress can expect his or her blood pressure to rise temporarily. However, persistent systolic blood pressure readings of 120 mm Hg or higher and diastolic readings of 80 mm Hg or higher are abnormal. If a person's blood pressure persists at systolic values that are greater than or equal to (≥) 130 mm Hg and diastolic values that are ≥ 80 mm Hg, he or she has a form of hypertension. Major Risk Factors for Hypertension: A table shows major risk factors of hypertension. Family history Advanced age African-American ancestry Obesity Physical inactivity Consuming excess sodium Cigarette smoking Consuming excess alcohol Type 2 diabetes Osteoporosis -Osteoporosis is a chronic disease characterized by loss of bone mass and reduced bone structure (see Figure 9.12). People with osteoporosis have weak bones that are susceptible to fractures. In the United States, osteoporosis is a major public health problem. More than 10 million Americans have osteoporosis, and another 34 million are at risk of the disease because they have loss of bone mass.5 Most people with osteoporosis are older adult women. -In the United States, half of women and up to one-fourth of men who are over 50 years of age will have an osteoporosis-related fracture at some point.14 Many people do not realize their bones are becoming weaker and they have osteoporosis until they experience a fracture. People with osteoporosis may break a bone by falling, or they may experience spontaneous fractures in which the fragile bone shatters for no apparent reason. Osteoporosis-related fractures often involve the spine, hip, wrist, or ankle bones. In severe cases, bones in the upper spine fracture and then heal in an abnormally curved position, giving the obvious appearance associated with osteoporosis -Fractures, especially hip fractures, can be devastating events, especially for older adults. One in five older Americans who experiences a broken hip dies of complications related to the fracture within 1 year of the injury Factors People Cannot Change: • Being a woman • Growing older • Having white or Asian ancestry (confers the highest risk) • Having a family history of osteoporosis • Having a small, thin-boned body frame Factors People Can Change: • Having low estrogen levels in women, low testosterone levels in men • Having anorexia nervosa • Following long-term diets that contain inadequate amounts of calcium and vitamin D • Being physically inactive • Smoking cigarettes • Consuming excess alcohol Normal BP S <120 D <80 Elevated BP S 120-129 D < 80 Hypertension stage 1 S 130-139 D 80-89 Hypertension stage 2 S >140 D >90 CRISIS S >180 D >120

Explain why protein-energy malnutrition is a serious nutritional state, especially for young children.

In many parts of the world, the lack of foods containing high-quality proteins is a serious problem, particularly for young children. Protein deficiency interferes with a child's normal growth and development, and contributes to many childhood deaths. When food is limited, it is often more difficult for children to obtain nutritionally adequate diets than for adults to do so. Why? Adults may be able to consume enough plant proteins to meet their protein and energy needs, but children have smaller stomachs and higher energy and protein needs per pound of body weight than adults. They are unable to eat enough plant foods to meet their relatively high protein and other nutrient requirements Children whose diets lack sufficient protein and energy do not grow and are very weak, irritable, and vulnerable to dehydration and infections, such as measles, that can kill them. If these children survive, their growth may be permanently stunted and their intelligence may be lower than normal because undernutrition during early childhood can cause permanent brain damage. Kwashiorkor primarily occurs in developing countries where mothers commonly breastfeed their infants until they give birth to another child. The older youngster, who is usually a toddler, is fairly healthy until abruptly weaned from his or her mother's milk to make way for the younger sibling. Although the toddler may obtain adequate energy by consuming a traditional diet of cereal grains, the diet lacks enough complete protein to meet the youngster's high needs, and he or she soon develops signs of protein deficiency. Children affected by kwashiorkor have stunted growth, unnaturally blond, sparse, and brittle hair; and patches of skin that have lost their normal coloration. Children with kwashiorkor have some subcutaneous (under the skin) fat and swollen cheeks, arms, legs, and bellies that make them look well fed, but their appearance is misleading. An important function of certain proteins in blood is to maintain proper fluid balance within cells and blood vessels, as well as between cells. During starvation, levels of these proteins decline, resulting in edema, which can make the protein-deficient child look plump and over-fed instead of thin and undernourished. In many cases, the child suffering from kwashiorkor does not obtain enough energy and eventually develops marasmic kwashiorkor, a condition characterized by edema and wasting (loss of organ and muscle proteins)

Identify lifestyle practices associated with increased risk for certain cancers.

Medical researchers have discovered several risk factors for many forms of the disease, including the following: Aging (80% of cancers occur in people over 55 years of age) Having a family history of cancer Using tobacco Being exposed to some forms of radiation Being exposed to certain environmental substances, such as irritants Having certain viral and bacterial infections Having elevated levels of certain hormones Consuming alcohol and certain foods Being physically inactive and having excess body fat

List essential minerals and their possible roles in the body: focus on arsenic.

Methionine metabolism, growth, and reproduction (animal studies) No UL has been established; however, inorganic arsenic is highly toxic. Long-term exposure to arsenic may contribute to heart disease and certain cancers. Fish, rice, fruits, vegetables

Describe ways to improve intakes of major minerals without relying on dietary supplements: focus on calcium, sodium, potassium, magnesium.

Na -Most uncooked vegetables, raw meats, and grain products are naturally low in sodium. Thus, most of the sodium Americans consume is from foods available from restaurants and the salt that is added to food during processing (including curing, pickling, and canning).17 As a food additive, salt enhances flavors and can prevent the growth of microorganisms responsible for food spoilage. Other food additives that contain sodium include sodium nitrate, sodium citrate, and monosodium glutamate (MSG), a seasoning that is often added to foods served in Chinese restaurants. In the United States, the leading sources of dietary sodium include breads and rolls, pizza, sandwiches, deli meats, soups, burritos, tacos, and salty snacks.18 Table 9.9 lists some selected foods and indicates how much sodium is in a serving of each food. To rate your sodium intake, take the Sodium Intake Assessment that is in this section of the chapter. Ca -Fluid milk, yogurt, and cheese provide most of the calcium in American diets.5 Moreover, the calcium in milk products is well absorbed and used by the body. Not all products made from milk are rich sources of calcium. Cottage cheese, for example, does not supply as much calcium as the milk from which it is made because the milk loses as much as half of its calcium content when it is processed to make cottage cheese. Although butter, sour cream, and cream cheese are made from whole milk, people generally do not eat enough of these high-fat foods to contribute much calcium to their diets. K -Overall, fresh fruits and vegetables, and fruit and vegetable juices are good dietary sources of potassium. Milk, whole grains, dried beans, and meats are also major contributors of potassium to American diets Mg -Magnesium is in chlorophyll, the green pigment in plants. Therefore, it is not surprising that plant foods such as spinach, green leafy vegetables, whole grains, beans, nuts, seeds, and chocolate are the richest sources of magnesium. Animal products, such as milk and meats, also supply some magnesium. Table 9.14 lists some commonly eaten foods that supply magnesium. Refined grains are generally low in magnesium because the magnesium-rich bran and germ are removed during processing -Other sources of magnesium are "hard" tap water and dietary supplements. However, amounts of magnesium in tap water can vary considerably. Moreover, the body does not absorb the form of magnesium (magnesium oxide) in multivitamin/mineral supplements very well. Nevertheless, hard water and magnesium supplements can still contribute to meeting a person's magnesium needs.

List the primary function of proteins in the body.

Proteins are complex organic molecules that are chemically similar to lipids and carbohydrates because they contain carbon, hydrogen, and oxygen atoms. Proteins, however, are the only macronutrient that contains nitrogen, the element cells need to make a wide array of important biological compounds. Proteins are necessary for muscle development and maintenance, but the more than 200,000 different proteins in your body have a wide variety of functions: • New cells and many components of cells • Structures such as hair and nails • Enzymes • Lubricants • Clotting compounds • Antibodies • Compounds that help maintain fluid and pH balance • Certain hormones and neurotransmitters • Energy source (minor, under usual conditions) Certain hormones, such as insulin and glucagon, are proteins. Some neurotransmitters are proteins. Nearly all enzymes are proteins. Enzymes speed up the rate of (catalyze) chemical reactions without becoming a part of the products. Additionally, infection-fighting antibodies are proteins Proteins in blood, such as albumin, also help maintain the proper distribution of fluids in blood and body tissues. The force of blood pressure moves watery fluid out of the bloodstream and into tissues. Blood proteins help counteract the effects of blood pressure by attracting the fluid, returning it to the bloodstream. During starvation and some chronic illnesses, the level of protein in blood decreases, and as a result, some water leaks out of the bloodstream and enters spaces between cells. The resulting accumulation of fluid in tissues is called edema Proteins also help maintain acid-base balance, the proper pH of body fluids. To function properly, blood and tissue fluids need to maintain a pH of 7.35 to 7.45, which is slightly basic

Explain what can happen when dehydration occurs.

Sweating can cause the body to lose a significant amount of "water weight"; however, sweating can also cause dehydration (body water depletion), especially when a person restricts his or her fluid intake. Severe dehydration is a life-threatening condition that requires urgent medical care. At 3 p.m. on November 6, the college wrestler began exercising vigorously in a hot environment. By 11:30 p.m., he had lost 9 pounds. After resting for about 2 hours, the young man resumed his exercise regimen in a desperate effort to lose the remaining 6 pounds. Around 2:45 a.m. on November 7, he had to discontinue exercising: He was extremely fatigued and unable to communicate. An hour later, he stopped breathing and his heart ceased beating. Attempts to revive him were unsuccessful. Hyperthermia (very high body temperature) is likely to have contributed to his death We often take water for granted, but this simple molecule is highly essential. You can survive for weeks, even months, if your diet lacks carbohydrates, lipids, proteins, and vitamins. But if you do not have any water, your life will end within a week or two.

Explain the role of the FDA and EPA in regulating water safety in the United States.

The Environmental Protection Agency (EPA) regulates the sanitation of public water supplies in the United States. Another federal agency, the FDA, regulates bottled water products that are marketed for interstate commerce. Neither agency "certifies" bottled water The FDA requires bottled water producers to: process, bottle, hold, and transport bottled water under sanitary conditions; protect water sources from bacteria, chemicals, and other contaminants; use quality control processes to ensure the bacteriological and chemical safety of the water; and sample and test both the source of water and the final product for contaminants

Compare the percentage of calories that protein contributes in the typical American diet to the AMDR for protein.

The Estimated Average Requirement (EAR) for protein is 0.66 g of protein/kg of body weight. The EAR for protein increases during pregnancy, breastfeeding, periods of rapid growth, and recovery from serious illnesses, blood losses, and burns. A healthy adult's RDA for protein is 0.8 g/kg of body weight. To determine your RDA for protein, multiply your weight in kilograms by 0.8 gram.

Describe what happens to excess amino acids in the body.

The body does not store excess amino acids in muscle or other tissues. The unnecessary amino acids undergo deamination, and cells convert the carbon skeletons into glucose or fat, or metabolize them for energy

Explain what happens to proteins as they undergo digestion and absorption in the human digestive tract: note difference between denaturation and enzymatic digestion.

When you eat oatmeal mixed with milk for breakfast, the large proteins in these foods must be digested before undergoing absorption. The chemical digestion of protein digestion begins in the stomach, where hydrochloric acid denatures food proteins and pepsin, an enzyme, digests proteins into smaller polypeptides. Soon after the polypeptides enter the small intestine, the pancreas secretes protein-splitting enzymes, including trypsin (trip′-sin) and chymotrypsin (ki′-mo-trip′-sin). Trypsin and chymotrypsin break down polypeptides into shorter peptides and amino acids. Enzymes released by the absorptive cells of the small intestine break down most of the shortened peptides into dipeptides, tripeptides, and individual amino acids that are absorbed. Within the absorptive cells, di- and tripeptides are broken down into amino acids. Thus, amino acids are the end products of protein digestion. After being absorbed, the amino acids enter the hepatic portal vein and travel to the liver, where they may enter the general circulation The protein digestion and absorption occurs as follows: Stomach: Proteins undergo denaturation by stomach acid, and partial digestion by pepsin. Small intestine: Further digestion occurs as the pancreas secretes protein-splitting enzymes, including trypsin and chymotrypsin. Small intestinal cells: Final digestion occurs within absorptive cells. Liver: After being absorbed, amino acids enter the hepatic portal vein and travel to the liver. Rectum: Very little dietary protein is excreted in feces.

Explain how to use the Nutrition Facts panel to determine the grams of protein in a serving of a packaged food. Explain how you can use the ingredient list on a food label to determine the quality of protein in the product.

You can determine how much protein is in a packaged food product by reading the Nutrition Facts panel on the label. As you can see in Figure 7.15, one serving of these crackers contains 3 g of protein. The Food and Drug Administration (FDA) does not require food manufacturers to include information about the % Daily Value for protein when the food is intended for adult consumption. However, the manufacturer has to display the %DV for protein when the label has a claim about the product's protein contents. Most Americans consume plenty of protein, so protein intake is not a public health concern. The Daily Value for protein (adults) is 50 g. The panel does not provide information about a product's protein quality, but you can judge from the list of ingredients.

Classify mineral nutrients as major, trace, or possible essential minerals.

major Ca Cl Mg P K Na S trace Cr Cu F I Fe Mn Mo Se Zn possible essential As B Li Ni Si V

Identify health problems associated with excesses and deficiencies of fat-soluble vitamins: Focus on A, D, E, K

A -Night blindness, xerophthalmia, poor growth, dry skin, reduced immune system functioning D -Rickets in children, osteomalacia in adults: soft bones, depressed growth, and reduced immune system functioning E -Loss of muscular coordination, nerve damage, reduced immune system function K -Excessive bleeding

Describe how the body maintains its water balance: no questions about osmosis on exam but you should know the mineral ions that are important in maintaining water balance. Know role of kidneys, diuretics.

Ions that conduct electricity, such as sodium and potassium ions, are called electrolytes. Maintenance of intracellular fluid volume depends to a large extent on the intracellular concentration of potassium and phosphate ions (Fig 9.4). On the other hand, maintenance of extracellular fluid volume depends primarily on the extracellular concentration of sodium and chloride ions (see Figure 9.4). Changes in the normal concentrations of these ions can cause water to shift out of one compartment and move into the other. For example, if extracellular fluid has fewer than normal sodium ions, water moves from the extracellular compartment into cells. When this occurs, the cells swell and can burst (Fig. 9.5a). On the other hand, if extracellular fluid has an excess of sodium ions, water moves out of cells. As a result, the cells shrink and die because they lack enough intracellular fluid to function (Fig. 9.5b). Recall from Chapter 7 that edema occurs when an excessive amount of fluid is in the space surrounding cells (see Figure 7.1). To function normally, the body must maintain intracellular and extracellular fluid volumes within certain limits. An average healthy adult consumes and produces approximately 2.6 quarts (2500 ml) of water daily (Fig. 9.6).4 The body eliminates about 2.6 quarts of water in urine, exhaled air, feces, and perspiration (see Figure 9.6). Thus, a healthy person's average daily water intake equals his or her average daily losses (output). Various factors influence a person's water intake and output. Environmental factors such as temperature, humidity, and altitude can affect body water losses. Physiological conditions, especially fever, vomiting, and diarrhea, as well as lifestyle practices, including exercise habits and sodium and alcohol intakes, can also alter the body's fluid balance. Perspiration is body water that is secreted by sweat glands in skin. When perspiration reaches the skin's surface, it evaporates into the air. This process helps cool the body and maintain its normal temperature. Insensible perspiration is body water that diffuses through the layers of skin or is exhaled from the lungs instead of being secreted by sweat glands.4 People are usually unaware that their bodies are constantly losing water in this manner; hence, the term insensible perspiration. The kidneys are the major regulator of the body's water content and ion concentrations. In a healthy person, the kidneys maintain proper hydration by filtering excess ions and water from blood as it flows through the kidney's tissues. Water is the main component of urine. If you drink more watery fluids than your body needs, your kidneys excrete the excess water in urine. Kidneys also remove drugs and metabolic waste products, such as urea, from the bloodstream. Sometimes, minerals and waste products settle out of urine and collect into crystals. If the crystals enlarge and form a hard mass, the object is called a kidney stone (Fig. 9.7). Kidney stones often contain the mineral calcium.5 As a kidney stone moves out of the kidney and enters the tube leading to the bladder, it may cause considerable pain and bloody urine until it passes out of the body. Dehydration increases the likelihood of forming kidney stones. Caffeine is a diuretic, a substance that increases urine production. Coffee, tea, energy drinks, and soft drinks often contain caffeine or caffeine-related compounds. However, the water consumed in caffeinated beverages is not completely lost in urine, so drinking these fluids may still contribute to meeting your water needs. As mentioned in the beginning of this chapter, body water depletion is called dehydration. Dehydration can be a life-threatening condition. When you are hot and perspiring heavily, your kidneys try to conserve as much water as possible to avoid dehydration. Antidiuretic hormone (ADH) and aldosterone (al-dahs′-te-rown) are two hormones that participate in the body's efforts to maintain fluid balance. In response to dehydration, the posterior pituitary gland in the brain releases antidiuretic hormone. Antidiuretic hormone stimulates the kidneys to conserve water. Additionally, the adrenal glands secrete aldosterone. Aldosterone signals kidneys to reduce the elimination of sodium in urine, and as a result, the kidneys return the mineral and water to the general circulation.

Explain what causes celiac disease, identify foods that a person with celiac disease must avoid, and list three common signs of symptoms of the disease.

Celiac (see′-lee-ak) disease is a common inherited condition that results in poor absorption of nutrients (malabsorption) from the small intestine. People with the disease cannot tolerate foods that contain gluten, a group of related proteins in wheat, barley, and rye. After a person with celiac disease eats foods or is exposed to substances that contain gluten, a component of the protein stimulates the body to mount an immune response in the small intestine that inflames or destroys villi. The signs and symptoms of celiac disease vary from person to person but usually include abdominal bloating, chronic diarrhea, and weight loss. Children with this condition also experience poor growth due to nutrient malabsorption and protein malnutrition. Some people have no obvious signs or symptoms of the disease, despite the damage occurring to their small intestines. Serious health problems such as anemia (a blood disorder), osteoporosis (weak bones), infertility, liver disease, and intestinal cancer can result from untreated celiac disease. A serious viral infection or severe emotional stress, for example, may activate the disorder in a genetically susceptible person.

Describe different forms of vegetarianism.

• Semivegetarian (flexitarian) All except red meats • Lactovegetarian Milk and milk products No animal flesh or eggs • Ovovegetarian Eggs but no other animal foods • Lactoovovegetarian Milk and milk products and eggs but no other animal foods • Pescatarian Fish and shellfish but no other animal foods • Vegan No animal foods Fruitarian No animal foods (nuts and seeds only) Macrobiotic No animal foods (will eat organically grown whole grains, fruits and vegetables, and soups made with vegetables, seaweed, grains, beans, and miso)

Explain the cause of a food allergy, identify foods that are the most likely to cause food allergies in vulnerable people, and list three common signs or symptoms of a food allergy.

A food allergy is an inflammatory response that results when the body's immune system reacts inappropriately to one or more harmless substances (allergens) in the food. In most instances, the allergen is a protein. People with food allergies may experience swelling of their lips and tongue as they eat the food or soon after they swallow it. If the allergen in the food that is eaten does not undergo denaturation by stomach acid, the molecule enters the small intestine. Immune system cells in the small intestine may recognize the food protein as a foreign substance and try to protect the body by mounting a defensive response. In other instances, the cells of the small intestine absorb the food allergen, and the body's immune system reacts to it. As a result of the immune response, the person who is allergic to that food experiences typical signs and symptoms. Common signs and symptoms of food allergies include hives, red raised bumps that usually appear on the skin; swollen or itchy lips; skin flushing; a scaly skin rash (eczema); difficulty swallowing; wheezing and difficulty breathing; and abdominal pain, vomiting, and diarrhea. Allergic reactions generally occur within 30 minutes to a couple of hours after eating the offending food. In severe cases, sensitive people who are exposed to food allergens can develop anaphylactic shock, a serious drop in blood pressure that affects the whole body. Anaphylaxis (an-a-pha-lax′-is) can be fatal, unless emergency treatment is provided. Genetics play a major role in the risk of food allergies; people who have family histories of allergies to foods are more likely to develop these conditions. Although any food protein has the potential to cause an allergic reaction in a susceptible person, the most allergenic proteins are in cow's milk, eggs, peanuts and other nuts, wheat, soybeans, fish, and shellfish. Allergic responses to nonprotein food dyes or other food additives such as sulfites can also occur.

Explain the concept of nitrogen balance and identify conditions in which the body is in a state of positive or negative nitrogen balance.

A healthy human body can make 11 of the 20 amino acids. The liver is the main site of nonessential amino acid production. Chemical reactions called deamination and transamination are involved in the synthesis of amino acids. Deamination is the process of removing the nitrogen-containing group (usually NH2) from an unneeded amino acid. As a result of deamination, the amino acid that gives up its amino group becomes a carbon skeleton Deamination occurs primarily in the liver. After an amino acid undergoes deamination, the carbon skeleton that remains can be used for energy or converted to other compounds, such as glucose. Transamination occurs when the nitrogen-containing group is transferred to another substance to make an amino acid. To make the amino acid alanine, for example, liver cells remove the amino group (NH2) from glutamic acid and transfer it to pyruvic acid (reversible) Normally, an adult's body maintains its protein content by maintaining nitrogen balance (equilibrium), that is, balancing nitrogen intake and protein turnover with losses. During certain stages of life or physical conditions, however, nitrogen intake and retention do not equal nitrogen losses. When the body is in a state of positive nitrogen balance, it retains more nitrogen than it loses as proteins are added to various tissues. In this case, a person must eat more protein to satisfy the increased need for the nutrient. Positive balance occurs during periods of rapid growth such as pregnancy, infancy, and puberty, and when people are recovering from illness or injury. Hormones such as insulin, growth hormone, and testosterone stimulate positive nitrogen balance. Performing weight (resistance) training also leads to nitrogen retention. When the body is in a state of negative nitrogen balance, the body loses more nitrogen than it retains and protein intake is less than what the body needs. Negative balance occurs during starvation, serious illnesses, and severe injuries. Recovery from the illness or injury results in positive nitrogen balance until nitrogen equilibrium is restored In positive nitrogen balance the protein turnover and nitrogen intake is more and nitrogen losses are less. Growth, Pregnancy, Recovery from illness/injury, Increased levels of the hormones insulin, testosterone, and growth hormone, and Resistance exercise. In nitrogen equilibrium both protein turnover and nitrogen intake as well as nitrogen losses are equal. Healthy adult meets protein and energy needs. In negative nitrogen balance the protein turnover and nitrogen intake is less and nitrogen losses are more. Inadequate protein intake or digestive tract diseases that interfere with protein absorption, Increased protein losses resulting from certain kidney diseases or blood loss, Bed rest, fever, injuries, or burns, and Increased secretion of thyroid hormone or cortisol (an open quotes stress hormone closed quotes).

Define vitamin and explain how scientists determine whether a substance is a vitamin.

A vitamin is a complex organic compound that regulates certain metabolic processes in the body. A vitamin meets the following criteria: 1) The body cannot synthesize the compound or make enough to maintain good health. 2) The compound naturally occurs in commonly eaten foods. 3) Signs and symptoms of a health problem (deficiency disorder) eventually occur when the substance is missing from the diet. 4) Good health is restored, if the deficiency disorder is treated early by supplying the missing substance. Vitamins play numerous roles in the body, and each of these micronutrients generally has more than one function (Fig. 8.1). Some vitamins, such as vitamin D, act as hormones; other vitamins, such as thiamin, riboflavin, and niacin, are parts of special molecules that enzymes need to function. In general, vitamins regulate a variety of body processes, including those involved in cell division and development, as well as the growth and maintenance of tissues.

Identify foods that may increase risk of cancer.

According to results of observational and experimental studies, certain substances in foods and beverages promote cancer development. Alcohol, for example, is a carcinogen. People who consume alcoholic drinks daily have higher-than-average risks of cancers of the mouth, throat, esophagus, larynx, colorectum, liver, and breast. The risk rises as the amount of alcohol consumed increases and when cigarette smoking is combined with drinking. To reduce your risk of cancer, avoid alcoholic beverages or drink in moderation: no more than one standard drink per day for women and no more than two standard drinks per day for men Certain molds that can grow on nuts or grains produce a chemical called aflatoxin (ah′-fla-tox′-in). Consuming foods that are contaminated with these molds increases the risk of liver cancer. Although liver cancer is not common among Americans, populations that consume peanuts and grains that have been stored improperly have high rates of this type of cancer Diets that contain large amounts of processed meat and/or red meat (defined as beef, pork, and lamb) are associated with increased risk of colorectal and prostate cancer. Processed meat ("deli" meat) has sodium nitrate and sodium nitrite added to it during production. Under certain conditions, these chemicals form nitrosamines (ni-tros′-ah-menes), which are carcinogens. Eating high amounts of smoked or salt-preserved (pickled) foods, such as salted fish, may increase the risk of stomach cancer The high temperatures used to fry, grill, or broil meat may cause the formation of a group of substances in the food called heterocyclic (het′-eh-ro-si′-klic) amines. Results of animal studies indicate that these amines are carcinogens. However, it is not known whether heterocyclic amines are human carcinogens. Nevertheless, you may want to consider limiting your intake of grilled meats and avoiding charred parts of charcoal-grilled meats. Also, covering the grate with aluminum foil, poking a few holes in the foil, and placing the meat on top of it will reduce charring of the meat.

Describe factors that can affect retention of minerals during food preparation.

Compared to plant foods, animal foods tend to be more reliable sources of minerals, such as iron and calcium. Why? Animal products often have higher concentrations of these minerals. Additionally, plant foods can contain substances that reduce the bioavailability of minerals, particularly calcium, zinc, and iron. On the other hand, plants supply more magnesium and manganese than animal foods. In general, the more processing a plant food undergoes, the lower its natural mineral content. Cereal grains, for example, naturally contain selenium, zinc, copper, and some other minerals, but these micronutrients are lost during refinement. In the United States, iron is the only mineral added to grains if they undergo enrichment. To obtain a variety of minerals, include some whole-grain products in your diet each day. By following the recommendations of MyPlate (see Chapter 3) and eating a variety of plant and animal foods, you are likely to obtain adequate amounts of all essential minerals.

Explain how using mixtures of foods with complementary proteins can help reduce animal protein intake.

Complementary combinations are mixtures of certain plant foods that provide all essential amino acids without adding animal proteins. Most plant foods are poor sources of one or more essential amino acids, particularly lysine, tryptophan, cysteine, and methionine. Split peas, for example, are good sources of lysine, but they contain low amounts of cysteine and methionine. Cereal grains such as wheat, rice, and corn are good sources of cysteine and methionine, but they tend to be low in lysine. Wheat germ, however, is a rich source of lysine. Corn is low in tryptophan. Seeds such as sesame and sunflower seeds are generally low in lysine. Walnuts, cashews, almonds, and other tree nuts also contain low amounts of lysine. Although most fruits and some kinds of vegetables are poor sources of protein, they add appealing colors and textures, as well as vitamins, minerals, and phytochemicals, to plant-based meals. Many cultures have traditional foods that combine complementary plant proteins. For example, a peanut butter sandwich combines two foods that supply complementary plant proteins. Peanuts are a fair source of lysine. Bread contains some methionine, but the grain product is very low in lysine. Serving the two foods together as a peanut butter sandwich provides adequate amounts of these essential amino acids you can combine a variety of legumes, grains, tree nuts, and seeds with vegetables to prepare dishes that provide adequate mixtures of the essential amino acids

Explain why dehydration and water intoxication can be life-threatening conditions.

Despite the body's mechanisms to balance its water content, some fluid is constantly being lost, primarily via the skin and lungs. If a person does not consume enough fluids to replace that water, dehydration can occur. Rapid weight loss is a sign of dehydration. Every 16 ounces (about 0.5 L) of water that the body loses represents a pound of body weight. If you lose 1 to 2% of your usual body weight in fluids, you will feel fatigued and thirsty. If you weigh 150 pounds, for example, and your weight drops 3 pounds after exercising in hot conditions, you have lost 2% of your body weight, primarily as water weight. As the loss of body water approaches 4% of body weight, muscles lose considerable amounts of strength and endurance. By the time body weight is reduced by 7 to 10% as a result of body fluid losses, severe weakness results. At a 20% reduction of body weight, coma and death are likely. Thirst is the primary regulator of fluid intake.4 The thirst response alerts you to the need to replenish water that was lost by sweating and other means. The majority of healthy people meet their AI for water by letting thirst be their guide.3 Thirst stimulates people to drink fluids before severe dehydration occurs. However, people who are dehydrated and older than 60 years of age do not sense thirst as accurately as younger adults.8 Furthermore, older adults may be more susceptible to developing dehydration than younger persons because as kidneys age, they become less able to conserve water when fluid intakes are low. Therefore, it may be necessary to remind older adults to drink more watery fluids, especially when they are physically active or in warm conditions. Nevertheless, healthy older adults are generally able to maintain adequate hydration. People who are sick, especially children with fever, vomiting, diarrhea, and increased perspiration, may need to be given special solutions of water and electrolytes to prevent dehydration. Athletes and other people who work or exercise outdoors, especially in hot conditions, also need to stay properly hydrated to avoid dehydration and heat-related illnesses such as heat exhaustion. Water intoxication, however, can occur when an excessive amount of water is consumed in a short time period or the kidneys have difficulty filtering water from blood. The excess water dilutes the normal sodium concentration of blood, causing hyponatremia (hypo = low; natremia = sodium in the bloodstream). As a result of the water imbalance, too much water moves into cells, including brain cells. Signs and symptoms of water intoxication may include drowsiness, nausea and vomiting, confusion, inability to coordinate muscular movements, and weight gain.9 If the condition is not detected early and treated effectively, coma and death can result.

Describe potential health problems that may occur with excessive protein intake.

Excess intakes of dietary protein may lead to higher-than-normal urinary losses of calcium Protein-rich foods from animals, especially liver, eggs, meat, and certain fish, are rich sources of purines, nitrogen-containing chemicals that comprise genetic material, including DNA. The liver breaks down purines to form uric acid. Healthy kidneys remove uric acid from the bloodstream and excrete the waste product in urine. A diet that is high in animal proteins may increase the level of uric acid in the bloodstream and urine. Gout is a type of arthritis that can develop in people who have elevated blood levels of uric acid. The condition is characterized by the buildup of uric acid crystals in joints, especially in the foot and big toe. Medication is used to treat gout. Having an excess of uric acid in urine can contribute to the formation of kidney stones. Thus, people who have a history of kidney stones, have kidney disease, or are at risk of kidney disease should check with their physician before eating a high-protein diet Excess amino acid or protein intake can lead to dehydration because the kidneys need more water to dilute and eliminate the toxic waste products of amino acid metabolism in urine. Dehydration is a potentially life-threatening condition in which the body's water level is too low. People with liver or kidney diseases may need to avoid protein-rich diets and amino acid supplements because metabolizing the excess amino acids is a burden to their bodies.

List the key functions and good food sources of trace minerals: focus on iron and zinc.

Fe -Component of hemoglobin and myoglobin that carries oxygen Energy generation Immune system function -Meat and other animal foods, except milk; whole-grain and enriched breads and cereals; fortified cereals Zn -Component of numerous enzymes -Seafood, meat, whole grains

List the water-soluble vitamins, and identify good food sources of each vitamin (or its precursor): See Vitamins Listed in Table 8.7 on page 286. Focus on Folate, Ascorbic Acid (vitamin C), B-12, Thiamin, Riboflavin, Niacin.

Folate -Dark green, leafy vegetables; liver, legumes, asparagus, broccoli, orange juice, enriched breads and cereals (folic acid Ascorbic Acid (vitamin C) -Peppers, citrus fruits, papaya, broccoli, cabbage, berries B-12 -Animal foods, fortified cereals, fortified soy milk Thiamin -Pork, wheat germ, enriched breads and cereals, nutritional yeast Riboflavin -Milk, yogurt, and other milk products; enriched breads and cereals; liver Niacin -Enriched breads and cereals, beef, liver, tuna, salmon, poultry, pork, mushrooms

Identify health problems associated with excesses and deficiencies of water-soluble vitamins. Focus on Folate, Ascorbic Acid (vitamin C), B-12, Thiamin, Riboflavin, Niacin.

Folate -Megaloblastic anemia, diarrhea, neural tube defects in embryos Ascorbic Acid (vitamin C) -Scurvy: Poor wound healing, pinpoint hemorrhages, bleeding gums, bruises, depression B-12 -Pernicious anemia: Megaloblastic anemia and nerve damage resulting in paralysis and death Thiamin -Beriberi and Wernicke-Korsakoff syndrome: Weakness, abnormal nervous system functioning Riboflavin -Inflammation of the mouth and tongue, eye disorders Niacin -Pellagra: Diarrhea Dermatitis Dementia Death

Describe major functions of each water-soluble vitamin. Focus on Folate, Ascorbic Acid (vitamin C), B-12, Thiamin, Riboflavin, Niacin.

Folate -Part of coenzyme needed for DNA synthesis and conversion of cysteine to methionine, preventing homocysteine accumulation Ascorbic Acid (vitamin C) -Needed for connective tissue synthesis and maintenance; antioxidant; synthesis of neurotransmitters and certain hormones; immune system functioning B-12 -Part of coenzymes needed for various cellular processes, including folate metabolism; maintenance of myelin sheaths Thiamin -Part of coenzyme needed for carbohydrate metabolism and the metabolism of certain amino acids; may help neurotransmitter production Riboflavin -Part of coenzymes needed for carbohydrate, amino acid, and lipid metabolism Niacin -Part of coenzymes needed for energy metabolism

Distinguish between nutrigenetics and nutrigenomics

Human DNA has approximately 23,000 genes that code for protein synthesis ("the human genome").39 Nutritional genomics is a relatively new science that investigates the complex interactions among gene functioning, dietary choices, and the environment. Such interactions influence a person's health status. Nutritional genomics includes nutrigenetics, the study of how a person's genetic makeup affects the way his or her body responds to food. For example, people who are genetically vulnerable to develop celiac disease are healthy until they consume foods that contain gluten. Nutritional genomics also involves nutrigenomics, the study of how nutrients and other food components can affect a person's genetic expression. Gene expression results in protein synthesis. As mentioned earlier, newborns with a particular genetic defect develop PKU when they consume amounts of phenylalanine that are harmless to babies who do not have the defect. By providing a diet that is low in phenylalanine to newborns with PKU, the infants develop normally. Nutritional genomics may explain why special diets or dietary supplements can have different effects on the health of different individuals

Explain the difference between a major mineral and a trace mineral.

If we require 100 mg or more of a mineral per day, the mineral is classified as a major mineral; otherwise, the micronutrient is a trace mineral. The body also contains very small amounts of other minerals, such as nickel and arsenic. The essential nature of this particular group of minerals has not been fully determined, so we will refer to them as "possible essential minerals"

Evaluate the use of vitamin supplements with respect to their potential health benefits and hazards: note Vitamin C, megadose (p.312-313)

In 1970, Nobel Prize-winning American chemist Dr. Linus Pauling (1901-1994) published Vitamin C and the Common Cold. This bestselling book established the popular belief that megadoses of vitamin C could prevent colds. As a result of Pauling's claim, many Americans take megadoses of the micronutrient when they notice the first cold symptoms. In the years that followed the publication of Vitamin C and the Common Cold, Pauling became more convinced of vitamin C's health benefits. He claimed that large doses of vitamin C could battle a variety of diseases, including influenza, cancer, and CVD. He even believed the vitamin could slow the aging process. Despite Pauling's impressive credentials in chemistry, many conventional nutrition scientists have approached his ideas about vitamin C's health benefits with caution and skepticism. Can taking vitamin C protect you against infection by cold viruses? The evidence collected from several scientific studies indicates that routine vitamin C supplementation (200 mg or more of the vitamin daily) does not prevent colds in the general population.5 However, taking such large doses of the vitamin may reduce the duration of cold symptoms by a day or so. Additionally, vitamin C may reduce the severity of cold symptoms because the micronutrient acts like an antihistamine when taken in very large doses. According to findings of epidemiological studies, people who consume diets containing high amounts of vitamin C-rich fruits and vegetables have lower risk of cancer than people who do not eat much of these foods. Nevertheless, results of studies generally do not support the usefulness of taking vitamin C supplements to prevent cancer.5 There is some encouraging scientific evidence that intravenous (IV) administration of megadoses of vitamin C may be useful in treating cancer.5 The "Nutrition Matters" section in this chapter provides more information concerning the role of diet in cancer development and prevention. In some cases, these physiological responses are beneficial, but in other instances, vitamin excesses cause unpleasant and even dangerous side effects. Therefore, people should be just as cautious about using megadoses of vitamins as they need to be when taking medications. Consuming a wide variety of vitamins, antioxidants, and phytochemicals in their natural states and concentrations (in foods) may be the most effective way to lower your risk of CVD, cancer, and many other serious chronic diseases. Why? These substances probably work together to enhance health, and isolating them from their natural sources or synthesizing and concentrating them into supplements may reduce their usefulness and increase their risks.32 Therefore, nutrition experts recommend that adults eat a variety of fruits and vegetables each day rather than take antioxidant or phytochemical supplements.

Define vitamin enrichment and fortification: grain enrichment and milk fortification.

In the United States, the federally regulated grain enrichment program specifies amounts of four B vitamins (thiamin, riboflavin, niacin, and folic acid) that manufacturers must add to their refined wheat flour and certain other milled grain products if they choose to participate in the program. Grain enrichment helps protect Americans from developing the deficiency diseases associated with the lack of these vitamins. Grain enrichment, however, does not replace vitamin E, vitamin B-6, and several other micronutrients that were lost from the grains during refinement. This is the major reason why registered dietitian nutritionists and other nutrition experts promote regular consumption of whole-grain products, such as whole-wheat bread and brown rice. Fortification involves the addition during manufacturing of one or more vitamins (and/or other nutrients) to a wide array of commonly eaten foods. The vitamins that are added may or may not be in the food naturally. For example, milk is often fortified with vitamins A and D, and many ready-to-eat cereals have additional vitamins baked into or sprayed on them before packaging. Nutritional yeast is usually a rich source of thiamin, riboflavin, niacin, folate, and vitamin B-12, but most Americans do not eat the vitamin-fortified product. In the United States, vitamin fortification and enrichment of foods have improved vitamin intakes of Americans. However, some food manufacturers add vitamins to foods and beverages, particularly flavored, sugary drinks, that would otherwise be considered sources of empty calories. Many nutrition experts are concerned that by substituting such human-made products for more natural foods and beverages, Americans may consume excessive amounts of a few vitamins while reducing their intake of others.

Identify foods and beverages that have high and low water contents.

Lettuce95 Tomato95 Watermelon91 Milk, 1% fat90 Apple, with skin86 Avocado (Florida)79 Potato, white, baked with skin75 Banana75 Chicken, white meat, roasted65 Ground beef, 80% lean, broiled56 Bread, whole wheat39 Margarine, stick16 Crackers, saltines5 Vegetable oil0

Identify foods that are rich in sources of high-quality protein.

Meat, fish, poultry, eggs, and milk and other dairy products contain high-quality proteins. Egg protein generally rates very high for protein quality because it is easy to digest and has a pattern of essential amino acids that closely resembles that needed by humans.

Describe ways people can reduce the amount of meat in their diet without sacrificing protein quality.

One way you can lower your intake is to include only one animal source of protein in a meal and reduce its serving size. For example, if your breakfast is a 6-ounce slice of ham with two large fried eggs, you are obtaining over 400 kcal and 42 g of high-quality protein. That is enough protein in one meal to meet the RDA for a person who weighs 116 pounds. Instead of eating such a large serving of ham with the fried eggs, have 3 ounces of ham without the eggs, or skip the ham and eat just the eggs. Two fried eggs supply over 12 g of high-quality protein and only 190 kcal. An easy way to reduce your meat consumption is to replace meat with other high-quality protein sources. Eggs, milk, cheese, and yogurt are animal sources of high-quality protein that you can substitute for meat, fish, or poultry items in your diet. For example, simply have a cheese sandwich instead of eating a submarine sandwich made with various luncheon meats and cheeses. If you are interested in eating less fat, a serving of low-fat cottage cheese or low-fat yogurt makes a protein-rich substitute for the "sub" or cheese sandwich. Another way to reduce the amount of animal food in your diet and your food costs is to make meals that contain less animal protein and more plant protein. Pancakes, waffles, crepes, and cornflakes with milk are examples of breakfast foods that extend egg and milk proteins with large amounts of cereal proteins.

Identify the basic structural unit of proteins and its components: note amino acids contain nitrogen.

Proteins are composed of smaller chemical units called amino acids. The human body contains proteins made from 20 different amino acids Each amino acid has a carbon atom that anchors a hydrogen atom and three different groups of atoms: the amino or nitrogen-containing group, the R group, and the acid group. Note that the nitrogen atom is in the amino group. The R group varies with each type of amino acid, so it identifies the molecule as a particular amino acid, such as serine or lysine. When the nitrogen-containing group is removed, the R group, acid group, and anchoring carbon atom form the "carbon skeleton" of an amino acid

Describe factors that influence the body's ability to absorb and use minerals.

The digestive tract, however, does not absorb 100% of the minerals in foods or dietary supplements. The body's ability to absorb and use minerals (bioavailability) depends on many factors. A major factor is the body's need for the mineral. In general, requirements increase during periods of growth, such as infancy and puberty, and during pregnancy and breastfeeding. During these critical life stages, the bioavailability of minerals also tends to increase to help meet the body's demand.

Identify general functions of minerals in the body.

The minerals and their functions are as follows: Bone health: Calcium, Phosphorus, Iron, Zinc, Copper, Manganese, Fluoride, Magnesium; Fluid balance: Sodium, Potassium, Chloride, Phosphorus, Magnesium; Blood clotting: Calcium; Transmission of nerve impulse: Sodium, Potassium, Chloride, Calcium. Red blood cell formation: Iron, Copper; Muscle contraction and relaxation: Sodium, Potassium, Calcium, Magnesium; Cellular metabolism: Iron, Calcium, Phosphorus, Magnesium, Zinc, Chromium, Iodine, Copper, Manganese. Antioxidant defense: Selenium, Zinc, Copper, Manganese. Growth and development: Calcium, Phosphorus, Zinc.

Explain why all vitamins have been discovered.

Today, we know that scurvy results from a deficiency of vitamin C and that citrus fruits are among the richest dietary sources of the vitamin. Although Lind is often credited with having discovered the cure for scurvy, he did not suspect the disease resulted from the lack of something in the typical seafarer's diet. At that time, scientists were unaware that food contained vitamins. In 1911, Polish chemist Casimir Funk discovered a substance in an extract made from rice bran that he thought would cure the disease beriberi. Funk called the compound a "vitamine" (vita = necessary for life; amine = a type of nitrogen-containing substance) because of its chemical structure. The term vitamine was later modified to vitamin when scientists determined that there were several kinds of these substances in foods and not all were amines. By the end of the 20th century, scientists had added riboflavin, niacin, biotin, B-6, B-12, pantothenic acid, folate, ascorbic acid, A, D, E, and K to the list of vitamins. Humans also require choline, especially during prenatal (before birth) development. Like vitamin D, the body can make choline, but under certain conditions, the body does not synthesize enough to meet its needs. Choline is considered to be a vitamin-like essential nutrient. It is unlikely that any vitamin still need to be discovered. Why? Babies grow and thrive on infant formulas, synthetic liquid diets containing vitamins and other nutrients known to be essential for health. Additionally, very ill people who cannot eat solid food can be kept alive for years on liquid synthetic feedings that contain all known nutrients, including vitamins. If a vitamin remained undiscovered, infants and people who are unable to consume solid foods would not be able to survive on formula diets.

Classify an amino acid as essential or nonessential: and understand the difference between an essential vs. nonessential amino acid and their production vs. consumption.

Traditionally, nutritionists classify amino acids as either nonessential or essential according to the body's ability to make them. A healthy human body can make 11 of the 20 amino acids that are in its proteins. These compounds are the nonessential amino acids. The remaining nine amino acids are essential amino acids that must be supplied by foods because the body cannot synthesize them or make enough to meet its needs. Sometimes, nonessential and essential amino acids are referred to as "dispensable" and "indispensable" amino acids, respectively. Essential Histidine Threonine Isoleucine Tryptophan Leucine Valine Lysine Methionine Phenylalanine Nonessential Alanine Cysteine* Aspartic acid Glutamine* Asparagine Glycine* Glutamic acid Proline* Serine Tyrosine* Arginine*

Identify pros and cons of vegetarian diets.

Vegetarian diets are often lower in saturated fat and energy than "Western" diets that contain animal foods, particularly plenty of red meat. Compared to people who eat meat, vegetarians tend to have a lower risk of obesity, type 2 diabetes, hypertension, and certain cancers. Furthermore, vegans tend to be leaner than nonvegans. It is difficult, however, to pinpoint diet as responsible for vegetarians' health status. Why? Vegetarians often adopt other healthy lifestyle practices, such as exercising regularly; practicing relaxation activities, such as meditation; and avoiding tobacco products and excess alcohol. Compared to the typical American diet, vegetarian diets provide more fiber, soy protein, folate (a B vitamin), beta-carotene (a phytochemical that the body can convert to vitamin A), vitamins E and C, and the minerals potassium and magnesium.19 Furthermore, vegetarian diets often supply less saturated fat and cholesterol than diets that include animal foods. Poorly planned, plant-based diets may not contain enough vitamins B-12 and D, minerals iron and calcium, and omega-3 fatty acids to meet a person's nutritional needs.18 Plant foods contain little or no vitamin B-12, and there are few dietary sources of vitamin D other than fortified cow's milk. Furthermore, mineral nutrients such as calcium and iron are more available from animal than from plant foods. Plants often contain phytochemicals that interfere with the body's absorption of minerals, particularly iron, zinc, and calcium. Recall from Chapter 6 that the body is unable to make much DHA and EPA from alpha-linolenic acid, an essential omega-3 fatty acid. Vegetarians who do not consume fish may need to obtain DHA and EPA by eating certain algae or taking dietary supplements that contain the algae. Vegans can obtain vitamin B-12, vitamin D, iron, zinc, and several other micronutrients by consuming fortified foods, such as many brands of ready-to-eat cereal, soy and rice beverages, and fortified vegetarian nutritional yeast. Vegetarians can also take a daily multiple vitamin/mineral supplement to provide dietary "insurance." Vegan women who breastfeed their infants may produce milk that is deficient in vitamin B-12, particularly if the mothers' diets lack the vitamin. These infants of vegan mothers have a high risk of developing severe developmental delays associated with neurological damage, especially when breast milk is their only source of vitamin B-12 Because plant foods add bulk to the diet, vegan children are likely to eat far less food than adult vegans because they become full sooner during meals. Thus, very young vegans may be unable to eat enough plant foods to meet their protein, micronutrient, and energy needs. Therefore, it is very important for parents or other caretakers to plan nutritionally adequate diets for vegetarian children and monitor the youngsters' growth rates.

Classify vitamins according to whether they are fat soluble or water soluble.

Vitamins A, D, E, and K are fat-soluble vitamins. These vitamins are in the lipid portions of foods and tend to associate with lipids in the body. Thiamin, riboflavin, niacin, vitamin B-6, pantothenic acid, folate, biotin, vitamin B-12 (collectively known as the B vitamins), and vitamin C are water-soluble vitamins. Water-soluble vitamins dissolve in the watery components of food and the body. (Choline is also water soluble.)

Explain the function of an antioxidant.

When many biochemical reactions take place, the compounds participating in the reactions lose or gain electrons. When an atom or molecule gains one or more electrons, it has been reduced. When an atom or molecule loses one or more electrons, it has been oxidized. An oxidizing agent is a substance that removes electrons from atoms or molecules. An oxidation reaction can form a radical (commonly referred to as a "free radical"), a substance with an unpaired electron. Radicals are highly reactive (chemically unstable), and they remove electrons from more stable molecules, such as proteins, fatty acids, and DNA (Fig. 8.3). As a result, radicals can damage or destroy these molecules. If the loss of electrons is uncontrolled, a chain reaction can occur in which excessive oxidation takes place and affects many cells. Many medical researchers suspect excess oxidation is responsible for promoting chemical changes in cells that ultimately lead to heart attack, stroke, cancer, Alzheimer's disease, and even the aging process. Some radical formation in the body is necessary and provides some benefits. Radicals, for example, stimulate normal cell growth and division. Additionally, white blood cells generate radicals as part of their activities that destroy infectious agents. Under normal conditions, cells regulate oxidation reactions by using antioxidants such as vitamin E. Antioxidants protect cells by giving up electrons to radicals. When the chemically unstable substance accepts an electron, it can form a more stable structure that does not pull electrons away from other compounds. By sacrificing electrons, antioxidants protect molecules such as polyunsaturated fatty acids in the membrane or DNA in the nucleus from being oxidized

Explain how cells make protein: note role of genes.

Your body makes proteins by following information coded in your DNA, or deoxyribonucleic (de-ox′-e-rye′-bow-new-klay′-ik) acid, the hereditary material in a cell's nucleus. To make proteins, cells assemble the 20 amino acids in specific sequences according to the information provided by DNA. The steps of protein synthesis are as follows: Protein synthesis begins when a section of DNA unwinds, exposing a single portion (a gene). The gene contains coded information about the order of amino acids that comprise a specific protein. The gene undergoes transcription, that is, the sequence of its amino acids is copied in a special manner, forming messenger RNA (mRNA)in the process. mRNA transfers the information concerning the amino acid sequence from the nucleus to ribosomes, protein manufacturing sites in the cytoplasm. During the translation process, ribosomes open quotes read closed quotes mRNA. The coded instructions indicate which amino acid to add to the polypeptide chain and its sequence. Each specific transfer RNA (tRNA)molecule conveys a particular amino acid to the ribosome. At the ribosome, the amino acid that has been delivered by tRNA attaches to the peptide chain, lengthening it. When the translation process is complete, the ribosome releases the polypeptide, and the new protein generally undergoes further processing at other sites within the cytoplasm.

Describe deficiency and toxicity disorders associated with the trace minerals: focus on iron and zinc. .

Zn -Skin rash Diarrhea Depressed sense of taste and smell Hair loss Poor growth and physical development -UL = 40 mg/day Intestinal upset Depressed immune system function Supplement use can reduce copper absorption. Fe -Fatigue upon exertion Small, pale red blood cells Low hemoglobin levels Poor immune system function Growth and developmental retardation in infants -UL = 45 mg/day Intestinal upset Organ damage Death

Describe the functions of water in the body as well as typical sources of intake and loss: also percentage of human body that is water.

• is a solvent • is a major component of blood, saliva, sweat, tears, mucus, joint fluid • removes wastes • helps transport substances • lubricates tissues • regulates body temperature • helps digest foods • participates in many chemical reactions • helps maintain proper blood pH Depending on a person's age, sex, and body composition, 50 to 75% of his or her body is water weight. Lean muscle tissue contains more water (about 73%) than fat tissue (about 20%). On average, young adult men have more lean tissue than young women. Approximately 60% of an average young man's body weight is water; the average young adult woman's body has more fat and, therefore, slightly less water than an average young man's body. A person's percentage of body weight that is water declines from birth to old age. Total water intake refers primarily to water ingested by consuming beverages and foods. The Adequate Intake (AI) for total water intake is approximately 11 cups (2.7 L) for young women and approximately 15.5 cups (3.7 L) for young men. Fruits and vegetables appear to be solid, but they generally contain 60 to 95% water weight. About 80% of our total water intake is from water and other beverages; food supplies the remaining amount of our water intake