CH-1-9 Nutrition, Food Choices, and Health – Wardlaw’s Contemporary Nutrition : Book Guide

This Document Contains Chapters 1 to 9 CHAPTER 1 1. Describe the process that controls hunger and satiety in the body. List other factors that influence our food choices. (LO 1.1) Hunger is a physiological drive to eat, and is controlled by internal body mechanisms. As nutrients are processed by the stomach and small intestine, these organs communicate with the liver and brain, reducing further food intake. The liver also uses its direct nerve pathways to the brain to signal hunger and fullness. The hypothalamus, a portion of the brain, helps to regulate hunger and satiety. The feeding center of the hypothalamus signals the body to eat, whereas the satiety center signals the body to stop eating. Besides hunger – the internal, physiological drive to find and eat food – many external factors contribute to food choices. Some of these factors include flavor, texture, and appearance of foods; early life experiences; routines or habits; advertising; social changes; economics; and nutrition knowledge. 2. Describe how your food preferences have been shaped by the following factors: a. Exposure to foods at an early age b. Advertising (what is the newest food you have tried?) c. Eating out d. Peer pressure e. Economic factors (LO 1.1) Food choices are influenced by many factors: a. Being raised by a vegetarian mother, I was exposed to a wide variety of fruits and vegetables from a young age and never went through a picky stage or refused to eat vegetables. b. At the grocery store, there were coupons and free samples of a new type of cereal bar. I tried it, liked it, and purchased it for breakfast this week. c. Because we were in a hurry and stopped at a fast food restaurant, my food choices at lunch today were excessive in calories, fat, and sodium. d. At Thanksgiving dinner, my grandmother offered me a second helping of mashed potatoes and gravy. I didn’t want to hurt her feelings, so I ate the extra portion. e. Expenses play a major role in my diet patterns. As a college student, funds are limited, so I really try to eat inexpensive food items or those that are on sale. For example, I purchased canned peaches instead of fresh peaches. 3. What products in your supermarket reflect the consumer demand for healthier foods? For convenience? (LO 1.1) Many grocery stores now offer an organic aisle or health food aisle, which reflects a changing trend in consumer demands. In terms of convenience, the frozen food section has become larger than ever and many supermarkets now offer prepared meals, such as sandwiches and roasted chicken. 4. Name one chronic disease associated with poor nutrition habits. Now list a few corresponding risk factors. (LO 1.2) Cardiovascular disease is a chronic disease associated with poor nutritional habits. A few corresponding risk factors are high blood cholesterol, high blood pressure, inadequate physical activity, diabetes, and smoking. 5. Describe two sources of fat and explain why the differences are important in terms of overall health. ( LO 1.3) There are two basic types of fat, unsaturated fat and saturated fat. Plant oils tend to contain many unsaturated fatty acids, which make them liquid at room temperature. Certain unsaturated fatty acids are essential nutrients, and some may also lower blood cholesterol. Animal fats are often rich in saturated fatty acids, which make them solid at room temperature. Saturated fatty acids tend to raise blood cholesterol. 6. Identify three ways that water is used in the body. (LO 1.3) Individual answers will vary. Example: To name just a few functions, water acts as a solvent and lubricant, provides a medium for transport of nutrients and wastes, and helps to regulate body temperature. 7. Explain the concept of calories as it relates to foods. What are the values used to calculate kcal from grams of carbohydrate, fat, protein, and alcohol? (LO 1.4) A calorie is a measure of heat energy: the amount of heat it takes to raise the temperature of 1 gram of water 1°C. Energy is stored in the chemical bonds in the carbohydrates, fat, and protein in the foods we eat. We can use this chemical energy to perform body functions, from pumping ions across cell membranes to moving skeletal muscles. Foods generally provide calories from more than one source. The fuel value for a gram of carbohydrate is 4 kcal, a gram of fat is 9 kcal, a gram of protein is 4 kcal, and a gram of alcohol is 7 kcal. 8. A bowl of Panera’s broccoli cheddar soup contains 21 grams carbohydrate, 13 grams fat, and 12 grams protein. Calculate the percentage of calories derived from fat. (LO 1.4) 21 grams x 4 calories/gram of carbohydrate = 84 calories from carbohydrate 13 grams fat x 9 calories/gram of fat = 117 calories from fat 12 grams protein x 4 calories/gram of protein = 48 calories from protein 84 + 117 + 48 = 213 total calories 117 calories from fat/213 total calories = 0.55 x 100 = 55% calories from fat 9. According to national nutrition surveys, which nutrients tend to be under consumed by many North Americans? Why do you think this is the case? (LO 1.5) Some North Americans have inadequate intakes of iron, calcium, vitamin A, various B vitamins, vitamin C, vitamin D, vitamin E, potassium, zinc, and fiber. This is primarily because of an inadequate fruit, vegetable, and whole grain intake, as well as over-consumption of sugared soft drinks and snacks. 10. List four Healthy People 2020 objectives for the United States. How would you rate yourself in each area? Why? (LO 1.5 & 1.6) Four Healthy People 2020 objectives for the United States are as follows: a. Increase the proportion of adults who are at a healthy weight. At 5’7” and 140 pounds, I am at a healthy weight. b. Increase the variety and contribution of vegetables to the diets of the population ages 2 years and older. I usually consume one or two servings of vegetables per day. I should increase my consumption of vegetables. c. Reduce consumption of saturated fat in the population ages 2 years and older. I usually select poultry and fish instead of red meat, so these choices are lower in saturated fat. However, I should cut down on the amount of cheese I eat, as this is a source of saturated fat. d. Reduce consumption of sodium in the population ages 2 years and older. I prepare most of my foods at home rather than relying on fast food or frozen meals. This helps me to keep my sodium intake within a healthy range. 11. List five strategies to avoid weight gain during college. (LO 1.7) Five strategies to avoid weight gain during college are: a. Eat breakfast. b. Plan ahead to eat a balanced meal or snack every 3 to 4 hours. c. Limit liquid calories by drinking water instead of high-calorie soft drinks, fruit juice, alcohol, or coffee. d. Keep a stash of low-calorie, nutritious snacks, such as pretzels, light microwave popcorn, and fruit (fresh, canned, or dried). e. Exercise for at least 30 minutes at least 5 days a week. CHAPTER 2 1. How would you explain the concepts of nutrient density and energy density to a fourth-grade class (LO 2.1)? Calories give us energy. We need just enough calories to help us stay healthy, learn, and play. If we have too many calories, though, we might gain too much weight and feel tired and sick. We need to choose foods that have a lot of nutrition – vitamins and minerals to help us grow – but not too many calories. Nutrient-dense foods are good foods to eat. They give us a lot of healthy vitamins and minerals, but they do not give us too many calories. We should choose more foods that are nutrient dense, such as fruits, vegetables, eggs, and oatmeal. Energy density is another way to describe foods to help us make healthy choices. An energy-dense food has a lot of calories in a small amount of food. Some examples of energy-dense foods are cookies, chips, and peanut butter. Having a small amount of some energy-dense foods is fine, but we need to make sure we are getting good nutrition along with our calories. We should choose energy-dense foods like cookies and chips less often or in smaller amounts. Instead, choose nutrient-dense foods like apples and carrots to help us grow, learn, and play. 2. Describe the intent of the Dietary Guidelines for Americans. Based on the discussion of the Dietary Guidelines for Americans, suggest two key dietary changes the typical North American adult should consider making. (LO 2.2). Dietary Guidelines have been issued to help improve the health of all Americans, ages 2 and older. The guidelines emphasize balancing food intake with physical activity to manage body weight; increasing consumption of fruits, vegetables, whole grains, and low-fat dairy foods; and decreasing consumption of dietary some components such as solid fats, added sugars, and sodium. A major criticism is that these guidelines are very general. For example, cholesterol and salt consumption affect people in different ways. 3. What dietary changes would you need to make to comply with the healthy eating guidelines exemplified by MyPlate on a regular basis (LO 2.3)? A general change will be to avoid oversized portions. Specific changes would include increasing fruit and vegetable consumption at each meal so that fruits and vegetables cover half of the plate at each meal. Grains should be decreased to occupy only slightly more than one-fourth of the plate at each meal. However, at least half of my grains should be whole grains. I will fill the remaining space on each plate with sources of protein and change these to be more lean meats and poultry and plant sources of protein. I will include fish as a protein source twice a week. In addition I will have 2 to 3 cups of low-fat or fat-free dairy products each day or other rich sources of calcium. I will also choose foods such as soup, bread, and frozen meals that have the lower sodium numbers and drink water instead of sugary drinks. 4. Describe what would happen to the status of a nutrient in the body for a person who transitions from an overnourished to an undernourished state (LO 2.4). The status of a nutrient in an overnourished person may be potentially toxic, causing damage to the body. As the person decreases the intake of this nutrient, the status of the nutrient will drop down to adequate level of storage and blood levels of the nutrient. If the intake of the nutrient drops below the required amount, the status of the nutrient will drop resulting in a decline in body functions associated with the nutrient. This decline in nutrient status will lead to clinical symptoms. 5. What steps would you follow to evaluate the nutritional state of an undernourished person (LO 2.5)? Nutritional assessment would start with carefully recording and analyzing the person’s family health history. Next the person’s medical history would be evaluated, especially for any disease states or treatments that could decrease nutrient absorption or ultimate use. A list of medications taken and the person’s social history (e.g., marital status, living conditions) would also be analyzed. Most importantly, the five nutritional-assessment categories (ABCDEs) would be completed. These include anthropometric assessment of height, weight (and weight changes), skinfold thicknesses, and body circumferences. In addition, a biochemical assessment of the concentrations of nutrients and nutrient byproducts in the blood, urine, and feces, and the activities of specific blood enzymes would be completed. A clinical assessment would follow, during which a health professional would search for any physical evidence of diet-related diseases or deficiencies. Then a dietary assessment of at least the previous few days’ food intake would be done to determine any possible problem areas. Finally, an environmental assessment would provide further details about the living conditions, education level, and ability to purchase and prepare foods needed to maintain health. 6. How do RDAs and AIs differ from Daily Values in intention and application (LO 2.6)? Recommended Dietary Allowances (RDAs) are set for many nutrients. RDAs indicate the amount of a nutrient that is sufficient to meet the needs of 97% to 98% of individuals within a population group. Adequate Intakes (AIs) are the standard used when not enough information is available to set an RDA. AIs indicate the intake level of a nutrient that appears to maintain health. Whereas the RDAs and AIs are specific to certain population groups, such as children or pregnant women, the DVs are generic because it is not feasible to list nutrient recommendations for every population group on the food label. The DVs are usually based on the highest RDA or AI for vitamins and minerals. For nutrients such as fat and cholesterol, the DVs represent a maximum intake level based on a 2000-kcal diet. 7. What would you list as the top five sources of reliable nutrition information? What makes these sources reliable (LO 2.7)? Five reliable sources of nutrition information: a. Registered dietitians are reliable sources of nutrition information. They have completed rigorous classroom and field training and are required to earn continuing education credits to maintain their credentials. RDs are trained to translate complex scientific knowledge into practical nutrition advice for the public. b. Peer-reviewed scientific publications are a source of information on nutrition research. These journals publish studies that are well-designed and reviewed by experts in the field. It is important to remember, however, that nutrition recommendations are not based on the results of one study; multiple lines of evidence are required to support nutrition recommendations. c. Professional nutrition organizations, such as the Academy of Nutrition and Dietetics, are reliable sources of nutrition information. The Academy develops clinical practice guidelines, maintains an Evidence Analysis Library, and provides answers to frequently asked questions to help both professionals and the public identify sound nutrition information. d. Universities and medical centers are reliable sources of nutrition information. These institutions provide practical information for health professionals and patients. Many such websites, such as www.mayoclinic.com, display the Health on the Net symbol, which indicates that the publishers of the site are committed to disseminating ethical and high-quality health information. e. Government organizations that conduct nutrition research and develop nutrition guidelines are other sources of reliable nutrition information. The Food and Drug Administration, the U.S. Department of Agriculture, Health Canada, the Centers for Disease Control and Prevention, the National Institutes of Health, and the Food and Nutrition Board of the Institute of Medicine are examples of such organizations. Experts in the field conduct research, analyze the findings, and work together to formulate nutrition recommendations, such as the DRIs. 8. Dietitians encourage all people to read labels on food packages to learn more about what they eat. What four nutrients could easily be tracked in your diet if you read the Nutrition Facts panels regularly on food products (LO 2.8)? Four nutrients that can easily be tracked using food labels are vitamin A, vitamin C, calcium, and iron. These are the four nutrients that are commonly lacking in diets of some North Americans, and are essential for good health. 9. Define the USDA definition for the term “organic” (LO 2.8). Federal standards for organic foods require that at least 95% of ingredients (by weight) must have been produced without the use of chemical fertilizers or pesticides, genetic engineering, sewage sludge, antibiotics, or irradiation to be labeled “organic” on the front of the package. If the front label instead says “made with organic ingredients,” only 70% of the ingredients must be organic. For animal products, the animals must graze outdoors, be fed organic feed, and cannot be exposed to large amounts of antibiotics or growth hormones. 10. List some specific health claims can be made on food labels (LO 2.8). •A diet with enough calcium and vitamin D and a reduced risk of osteoporosis •A diet low in total fat and a reduced risk of some cancers •A diet low in saturated fat and cholesterol and a reduced risk of cardiovascular disease (typically referred to as heart disease on the label) •A diet rich in fiber—containing grain products, fruits, and vegetables—and a reduced risk of some cancers •A diet low in sodium and high in potassium and a reduced risk of hypertension and stroke •A diet rich in fruits and vegetables and a reduced risk of some cancers •A diet adequate in the synthetic form of the vitamin folate (called folic acid) and a reduced risk of neural tube defects (a type of birth defect) •A diet rich in fruits, vegetables, and grain products that contain fiber and a reduced risk of cardiovascular disease. •Oats (oatmeal, oat bran, and oat flour) and psyllium are two fiber-rich ingredients that can be singled out in reducing the risk of cardiovascular disease, as long as the statement also says the diet should also be low in saturated fat and cholesterol •A diet rich in whole-grain foods and other plant foods, as well as low in total fat, saturated fat, and cholesterol, and a reduced risk of cardiovascular disease and certain cancers •Fatty acids from oils present in fish and a reduced risk of cardiovascular disease •Margarines containing plant stanols and sterols and a reduced risk of cardiovascular disease CHAPTER 3 1. Identify at least one function of the 12 organ systems related to nutrition. (LO 3.3) All twelve organ systems work together in the body, and each system provides at least one key component to overall nutritional status. a. The cardiovascular system transports nutrients to body tissues. b. The lymphatic system aids in fat absorption. c. The nervous system detects sensation and controls physiological and intellectual functions, including those involved in appetite regulation. d. The endocrine system participates in the regulation of metabolism of nutrients through the actions of hormones. e. The immune system provides defense against foreign invaders. Good nutrition can boost the immune system through maintenance of the integrity of the skin, mucous membranes, and white blood cells, which protect against infection. f. The digestive system performs the mechanical and chemical processes of digestion and absorption of nutrients, and elimination of wastes. g. The urinary system removes waste products of nutrient metabolism from the blood and regulates water balance. h. The integumentary system prevents water loss and produces a substance that converts to vitamin D. i. The skeletal system serves as a depot for minerals, such as calcium and phosphorus. j. The muscular system produces body movement, maintains posture, and produces body heat. k. The respiratory system exchanges gases between the blood and the air, allowing excretion of the waste products of metabolism. l. Finally, the reproductive system performs the processes of reproduction and influences sexual functions and behaviors. Nutrition status, including adequate intake of calories, folate, and iron, contributes to healthy fetal development. 2. Draw and label parts of the cell, and explain the function of each organelle as it relates to human nutrition. (LO 3.2) Compare diagram to Figure 3-1. Functions of organelles: a. Plasma membrane: allows nutrients to move into and out of the cell. b. Cytoplasm: fluid of the cell in which nutrients may be dissolved. c. Mitochondria: convert energy from nutrients into a form cells can use. d. Cell nucleus: contains genetic information for making substances the cell needs. e. Endoplasmic reticulum: proteins are made here; these also take part in lipid synthesis, cell detoxification and calcium storage. f. Golgi complex: packages proteins for export from the cell. g. Lysosomes: digest foreign material. h. Peroxisomes: metabolize alcohol. 3. Trace the flow of blood from the right side of the heart and back to the same site. How is blood routed through the small intestine? Which class of nutrients enters the body via the blood? Via the lymph? (LO 3.4) Blood travels from the right side of the heart via pulmonary circulation to the lungs, where carbon dioxide is exchanged for oxygen. Once the blood is oxygenated, it travels back to the left side of the heart. The left ventricle pumps blood out to the rest of the body via the systemic circuit, delivering essential nutrients, oxygen, and water to all body cells. Nutrients and wastes are exchanged between the blood and cells across the cell membrane of the one-cell-thick capillaries. Blood then travels through the veins back to the heart. Nutrients are absorbed primarily from the lumen of the small intestine into the small intestinal cells. In the villi of the small intestine, capillaries and lacteals (lymph vessels) are in direct contact with these absorptive cells, such that absorbed nutrients can be transported into the blood or lymph. Monosaccharides, amino acids, short- and medium-chain fatty acids, water-soluble vitamins, and most minerals are absorbed into the capillaries and travel via the hepatic portal vein to the liver. Long-chain fatty acids and fat-soluble vitamins are taken up into the lymph. The lymph vessels later empty into the bloodstream so fats and fat-soluble vitamins can be delivered to the liver and body cells 4. Explain why the small intestine is better suited than the other GI tract organs to carry out the absorptive process. (LO 3.8) The small intestine is the best absorptive organ because it has the most surface area; the villi increase the surface area 600 times. This expanse of surface area allows for efficient absorption of nutrients. In addition, the small intestine lacks the mucus coating that limits absorption in the stomach. 5. Identify the five basic tastes. Give an example of one food that exemplifies each of these basic taste sensations. (LO 3.8) The four basic tastes are sweet (e.g., honey), salty (e.g., pickles), sour (e.g., lemon juice), and bitter (lemon rind). 6. What is one role of acid in the process of digestion? Where is it secreted? (LO 3.8) Acid denatures proteins, thus beginning the process of protein digestion in the stomach. Acid aids in converting some inactive digestive enzymes to their active forms. Acid solubilizes some minerals to enhance their absorption. Finally, it destroys bacteria and many other foreign substances in foods. Hydrochloric acid (HCl) is produced by parietal cells in the lining of the stomach. 7. Contrast the processes of active absorption and passive diffusion of nutrients. (LO 3.8) Passive absorption occurs when the nutrient concentration is higher in the lumen of the small intestine than in the absorptive cells; the difference in the nutrient concentration drives absorption because nutrients naturally move from areas of high concentration to areas of low concentration. Energy input is not required. Active absorption is the mechanism that makes it possible for cells to take up nutrients even when they are present in low concentration in the small intestine. It requires energy input and a specific carrier. 8. Identify two accessory organs that empty their contents into the small intestine. How do the digestive substances secreted by these organs contribute to the digestion of food? (LO 3.8) The gallbladder and pancreas are two accessory organs that empty their contents into the small intestine. The gallbladder releases bile, which breaks up fat globules to aid digestion in the small intestine. The pancreas releases bicarbonate, which helps to neutralize the contents of the small intestine, so that the intestinal wall will not erode. The pancreas also releases enzymes that digest the food. 9. In which organ systems would the following substances be found? chyme (LO 3.8), plasma (LO 3.4), lymph (LO 3.4), urine (LO 3.9) Chyme is found in the digestive system. Plasma is found in the cardiovascular system. Lymph is found in the lymphatic system. Urine is found in the urinary system. 10. Describe the nutrition-related diseases for which genetics or family history is considered to be an important risk factor. (LO 3.11) Many chronic diseases involve a genetic component. Genetic defects that alter metabolism of cholesterol or homocysteine contribute to development of cardiovascular disease among some people. Familial patterns in body weight and body fat distribution indicate a genetic link in the development of obesity. Both type 1 and type 2 diabetes have a hereditary component – they can be prevalent in families or within certain population groups, such as the Pima Indians. Some types of cancer, especially breast and colon cancers, are influenced by heredity as well. CHAPTER 4 1. Why do we need carbohydrates in the diet? (LO 4.3) We need carbohydrates to provide the body with energy. If carbohydrate consumption is inadequate, the body will deplete its stores of glycogen and then make the glucose it needs to support cell metabolism from body proteins. If inadequate carbohydrate intake continues for weeks at a time, the consequence is loss of body protein, as well as ketosis (byproduct of fat metabolism), and a general weakening of the body. 2. What are the three major monosaccharides and the three major disaccharides? Describe how each plays a part in the human diet. (LO 4.2) The three major monosaccharides are glucose, fructose, and galactose. The three major disaccharides are sucrose, maltose, and lactose. Monosaccharides are the simple sugars that serve as the basic unit of all carbohydrate structures. Glucose is the major sugar in the body and a primary energy source for cells. Fructose is found in fruit and is often converted to glucose in the body. Galactose is part of the sugar lactose found in milk. Sucrose is common table sugar. Lactose is milk sugar. Maltose is a breakdown product of starch and is fermented by yeast to produce the alcohol in beer and wine. 3. Why are some foods that are high in carbohydrates, such as cookies and fat-free milk, not considered to be concentrated sources of carbohydrates? (LO 4.3) Foods such as cookies and nonfat milk are not considered concentrated carbohydrate sources because they also contain fat (in the case of cookies) and/or protein (in the case of nonfat milk). 4. Describe the digestion of the various types of carbohydrates in the body. (LO 4.4) Some starch digestion occurs in the mouth due to the action of the enzyme salivary amylase. Carbohydrate digestion is finished in the small intestine by specific enzymes such as pancreatic amylase, sucrase, and lactase. Some plant fibers are fermented by the bacteria present in the large intestine. Undigested plant fibers end up in the feces. Single sugars mostly follow an active absorption process in the small intestine. They are then transported to the liver via a portal vein. 5. Describe the reason why some people are unable to tolerate high intakes of milk. (LO 4.4) Some people cannot tolerate high intakes of milk because they have lactose maldigestion or intolerance. In these individuals, for various reasons, the body’s production of the enzyme lactase declines. Lactase, present in the small intestine, is needed to break down the lactose in milk. When lactase is deficient or absent, some or all of the ingested lactose escapes digestion and travels intact to the colon. In the colon, bacteria ferment lactose to produce fatty acids and gases, leading to uncomfortable side effects such as cramping, bloating, and diarrhea. 6. List three alternatives to simple sugars for adding sweetness to the diet. (LO 4.3) Three alternatives to sugar are aspartame (Equal®), saccharin (Sweet ‘N Low®), and sucralose (Splenda®). 7. Outline the basic steps in blood glucose regulation, including the roles of insulin and glucagon. (LO 4.5) As monosaccharides from a meal are absorbed from the small intestine into the bloodstream, blood glucose concentration begins to rise. In response to elevated blood glucose levels, the pancreas releases the hormone insulin. Insulin stimulates cells (e.g., muscle and adipose) to take up glucose from the blood. Insulin also stimulates the liver to synthesize glycogen, a stored form of carbohydrate. By triggering glucose uptake into cells and storage of glucose as glycogen in the liver, insulin keeps glucose from rising too high in the blood. When blood glucose is low, glucagon is the hormone produced by the pancreas to prompt the breakdown of glycogen into glucose, which is then released from the liver into the bloodstream. These two hormones, insulin and glucagon, work together to keep blood glucose within a fairly narrow range. 8. What are the important roles that fiber plays in the diet? (LO 4.5) Fiber, especially insoluble varieties, provides mass to the stool, thus easing elimination. Soluble fibers can help control blood glucose in people with diabetes and also lower blood cholesterol. 9. Summarize current carbohydrate intake recommendations. (LO 4.6) The RDA is 130 grams of carbohydrates per day. This is the minimal amount of carbohydrates that will prevent body proteins from being broken down to supply glucose to cells. As a percentage of total calories, the Food and Nutrition Board’s Acceptable Macronutrient Distribution Range for carbohydrates is 45% to 65% of total kcal. In terms of carbohydrate choices, diets high in complex forms of carbohydrates are encouraged, with an emphasis on fiber-rich foods. The foods to emphasize include whole grain cereals, breads and pastas, fruits, vegetables, and legumes. The AI for fiber is 14 g/1000 kcal, which equates to about 38 grams per day for men and 25 grams per day for women. Sugar intake should generally be limited to 10% of calorie intake. 10. What, if any, are the proven ill effects of sugar in the diet? (LO 4.7) Excessive sugar in the diet increases the risk of developing dental caries. After a meal, some carbohydrates (especially sticky foods, like candy) remain on the teeth and are metabolized by acid-producing bacteria in the mouth. These acids demineralize teeth, leading to tooth decay. In addition, high-sugar foods provide empty calories – they supply excess energy with few essential nutrients. Habitually consuming excessive empty calories can lead to obesity and its range of comorbid conditions. CHAPTER 5 1. Describe the chemical structures of saturated and polyunsaturated fatty acids and their different effects in both food and the human body. (LO 5.2) A saturated fatty acid contains no carbon-carbon double bonds in its carbon chain. The carbon chain of a polyunsaturated fatty acid, on the other hand, contains two or more carbon-carbon double bonds. Triglycerides rich in saturated fatty acids tend to be solid at room temperature and those rich in polyunsaturated fatty acids are liquid at room temperature. Saturated fatty acids tend to increase levels of blood cholesterol in the body, and polyunsaturated fatty tend to lower blood cholesterol. 2. Relate the need for omega-3 fatty acids in the diet to the recommendation to consume fatty fish at least twice a week. (LO 5.7) One omega-3 fatty acid (alpha-linolenic acid) is an essential fatty acid; it must be included in the diet to maintain good health. A regular intake of the omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which can be made from alpha-linolenic acid, is recommended to decrease blood clotting and inflammatory processes. Fatty fish is a good source of these omega-3 fatty acids. The American Heart Association recommends eating fatty fish such as salmon at least twice a week. Fish is a heart-healthy alternative to other animal sources of protein, which can be high in saturated fat and cholesterol. 3. Describe the structures, origins, and roles of the four major blood lipoproteins. (LO 5.5) There are four major blood lipoproteins: very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and chylomicrons. Dietary fats first enter the bloodstream from the intestine as chylomicrons. These lipoproteins contain mostly triglycerides with a shell of phospholipids, cholesterol, and proteins. Chylomicrons bring dietary lipids to cells of the body. The remaining three lipoproteins originate mainly from the liver. The least dense lipoprotein made by the liver is VLDL. It contains cholesterol and triglycerides with a shell of proteins and lipids. The major role of VLDL is to carry lipids taken up and made by the liver to the cells of the body. Cells remove some of these triglycerides, increasing the density of the VLDL particles. The denser particles are then known as LDL. The major role of LDL is to carry cholesterol to the cells. HDL contains mostly protein. It is produced mainly by the liver and intestine. The major role of HDL is to aid in the removal of cholesterol from the body. 4. What are the recommendations from various health care organizations regarding fat intake? What does this mean in terms of food choices? (LO 5.7) There is currently no RDA for fat. We need about 4% of total calorie intake from plant oils to obtain the needed essential fatty acids. Most health care organizations advise limiting total fat intake to 35% of total calories or less. Saturated fat and trans fat intakes (combined) should not exceed 10% of total calories. Fatty fish is a rich source of omega-3 fatty acids and should be consumed at least twice a week. In terms of food choices, plant sources of fats (e.g., canola oil, olive oil, and safflower oil) should be emphasized over many animal sources of fats, such as lard. Most people would benefit from substituting fish for other meats in their diets for two or more meals per week. Trimming visible fat from meats and removing the skin from poultry before eating are two easy ways to reduce saturated fat intake. 5. What are two important attributes of fat in food? How are these different from the general functions of lipids in the human body? (LO 5.3) Flavor and texture are two key attributes of fat in food. In contrast, the general functions of fat in the body are to provide the body with energy, store energy for later use, insulate and protect the body, and transport fat-soluble vitamins. 6. Describe the significance of and possible uses for reduced-fat foods. (LO 5.6) Whereas humans tend to crave the flavor and texture fat brings to foods, the body actually only needs a very small amount of fat to perform its daily functions. Reduced-fat foods provide an opportunity to retain some of that flavor and texture without contributing so many extra calories. Reduced-fat foods can be substituted for full-fat versions when it comes to snacks, cheeses, meats, and margarines, to name a few. Used appropriately, reduced-fat foods can help to lower one’s overall calorie intake. It is important to keep in mind, however, that “low-fat” is not always synonymous with “low-calorie,” as many reduced-fat foods may have added sugar to improve flavor. Also, portion sizes are still important to maintaining a healthy weight, even if some foods are low in fat. 7. Does the total cholesterol concentration in the bloodstream tell the whole story with respect to cardiovascular disease risk? (LO 5.8) No, the total cholesterol concentration in the bloodstream does not tell the whole story with respect to cardiovascular disease risk. Other factors like age, gender, family history, diabetes, and smoking could increase risk. Additionally, not all cholesterol is bad cholesterol. Whereas decreases in LDL cholesterol help to reduce risk for cardiovascular disease, low HDL cholesterol is not healthy and considerably raises the risk for cardiovascular disease. 8. List the four main risk factors for the development of cardiovascular disease. (LO 5.8) The four common risk factors for the development of cardiovascular disease are smoking, hypertension, diabetes, and total cholesterol over 200 mg/dl (especially when LDL exceeds 130-160 mg/dl). 9. What three lifestyle factors decrease the risk of cardiovascular disease development? (LO 5.8) Some lifestyle factors that decrease the risk of cardiovascular disease are avoidance of smoking, participation in regular physical activity, and eating plenty of whole grains, fruits, and vegetables. 10. When are medications most needed in cardiovascular disease therapy, and how in general do the various classes of medications operate to reduce risk? (LO 5.8) Medications are a more aggressive treatment than diet therapy and are typically used in people who have already had a heart attack or who are at considerable risk for cardiovascular disease. Medications may work to lower cholesterol synthesis in the liver, bind bile acids to prevent their reabsorption from the small intestine, decrease triglyceride output by the liver, or lessen absorption of dietary cholesterol from the small intestine. CHAPTER 6 1. Discuss the relative importance of essential and nonessential amino acids in the diet. Why is it important for essential amino acids lost from the body to be replaced in the diet? (LO 6.1) Amino acids are the basic building blocks of protein, and the body needs 20 common types to function. Eleven of the amino acids are nonessential, meaning that they can be synthesized in the body if the right ingredients are present. The remaining nine are essential. They must be consumed in the diet because the body cannot synthesize enough of them to maintain health. To meet essential amino acid requirements, about 11% of the RDA for total protein for adults should come from essential amino acids. This is easily achieved by most Americans. 2. What is the role of cholecystokinin (CCK) in protein digestion? (LO 6.4) In the small intestine, the partially digested proteins (and fats) trigger the release of the hormone cholecystokinin (CCK) from the walls of the small intestine. CCK causes the pancreas to release protein-splitting enzymes, such as trypsin. 3. What is a limiting amino acid? Explain why this concept is a concern in a vegetarian diet. How can a vegetarian compensate for limiting amino acids in specific foods? (LO 6.8) The essential amino acid in smallest supply in a food or diet in relation to body needs is the limiting amino acid because it limits the amount of protein that the body can synthesize. For a person who follows an omnivorous diet, which includes the complete proteins provided by animal foods, the concept of limiting amino acids is of little concern. However, those following a vegetarian diet are not likely to consume such high-quality protein. For example, grains and nuts are low in the essential amino acids lysine, whereas vegetables and legumes and low in methionine. If only one of these plant sources of protein is consumed, the amino acid pool in the body will be limited and protein synthesis will cease. Vegetarians can compensate for this by eating complementary proteins, which in combination will provide high-quality protein for the diet. When different sources of plant protein are combined, they complement each other. For example, in a meal with beans and rice, the beans make up for the low lysine content of the rice and the rice makes up for the low methionine content of the beans. 4. Briefly describe the organization of proteins. How can this organization be altered or damaged? What might be a result of damaged protein organization? (LO 6.2) Protein synthesis is directed by the genetic code, which provides the blueprint for the order of amino acids in a protein chain. However, the sequence of amino acids in a protein only tells part of the story in terms of protein structure and function. Chemical interactions between amino acids in the protein chain cause folding of the protein chain into a specific three-dimensional structure. In addition, multiple protein chains may associate with one another to create a functioning protein. Treatment with acid or alkaline substances, heat, or agitation can denature a protein, damaging its three-dimensional shape so that it cannot function as needed. 5. Describe four functions of proteins. Provide an example of how the structure of a protein relates to its function. (LO 6.5) Proteins have many functions such as: producing vital body constituents, maintaining fluid balance, contributing to acid-base balance, and forming hormones and enzymes. An example of how structure relates to function can be seen in hemoglobin. Its coiled shape allows it to hold iron and bind oxygen. When an error in the DNA code leads to a defect in the structure of hemoglobin (as in sickle cell disease), the shape of red blood cells is distorted and the ability of red blood cells to carry oxygen is limited. 6. How are DNA and protein synthesis related? (LO 6.2) DNA and protein synthesis are related because DNA contains the coded instructions for protein synthesis. The nucleic acid sequence in a segment of DNA dictates which amino acids are included in the protein. 7. What would be one health benefit of reducing high-protein intake(s) to RDA amounts for some people? (LO 6.6) High-protein foods (e.g., meats and dairy products) are also typically high in fat. Therefore, reducing excess protein intake in the diet usually results in lowered saturated fat intake. This would be considered a benefit, since intake of saturated fat has been linked to cardiovascular disease. In addition, the nitrogen byproducts of protein metabolism must be excreted via the kidneys. In people with kidney disease, reducing protein intake may help to preserve kidney function. Excessive protein intake, which increases protein excretion, may also deplete the body of water and calcium. Reducing protein intake could improve hydration status and help to preserve bone minerals. 8. Which eight foods are the major sources of proteins that cause food allergies? (LO 6.3) The eight leading food allergens in the United States are milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, and soy. 9. Outline the major differences between kwashiorkor and marasmus. (LO 6.8) Kwashiorkor and marasmus are two types of undernutrition that are prevalent among children in developing countries. Kwashiorkor results primarily from inadequate protein intake. With kwashiorkor, the child is getting some food, but the food provides insufficient protein in relation to needs. The child experiences edema with maintenance of some subcutaneous fat tissue. Marasmus results primarily from extreme starvation – a deficiency of both protein and total calories. With marasmus, the child receives hardly any food at all and appears as skin and bones with little or no subcutaneous fat tissue. 10. What are the possible long-term effects of an inadequate intake of dietary protein among children between the ages of 6 months and 4 years? (LO 6.8) Two examples of the long-term effects of inadequate protein intake among children include a stunting of overall growth and an increased risk of infections. CHAPTER 7 1. Explain how nurture and nature can contribute to the development of obesity. What are the two most convincing pieces of evidence that both genetic and environmental factors play significant roles in the development of obesity? (LO 7.4) Both genetic (nature) and environmental (nurture) factors can increase the risk for obesity. The eventual location of fat storage is strongly influenced by genetics, particularly during pregnancy when gene expression is being imprinted on the fetus. Research studies have found that offspring born to obese mothers are at increased risk of obesity later in life. Studies in pairs of identical twins also give us some insight into the contribution of nature to obesity. Even when identical twins are raised apart, they tend to show similar weight gain patterns, both in overall weight and body fat distribution. It appears that nurture—eating habits and nutrition, which varies between twins raised apart—has less to do with obesity than nature does. There is also evidence that environmental factors play a significant role in the development of obesity. Some obese people begin life with a slower basal metabolism; maintain an inactive lifestyle; and consume highly refined, calorie-dense diets. These people in turn are nurtured into gaining weight, promoting their natural tendency toward obesity. Evidence indicates, however, that genes do not fully control destiny. Even with a genetic tendency toward obesity, individuals can attain a healthier body weight with increased physical activity and decreased calorie consumption. 2. How does energy imbalance, including the role of physical activity, lead to weight gain and obesity? (LO 7.1) Energy imbalance, when energy input is greater than energy output, results in positive energy balance. The excess calories consumed are stored, which results in weight gain. In adults, even a small positive energy balance is usually in the form of fat storage rather than muscle and bone and, over time, can cause body weight to climb. The alarming incidence of and recent increase in obesity in North America are partially the result of our inactivity. As we age, weight gain stems from a pattern of excess food intake coupled with limited physical activity and slower metabolism. 3. Define a healthy weight in a way that makes the most sense to you. (LO 7.3) A healthy weight should be a comfortable weight, both physically and emotionally. It is not necessarily measured by the numbers on the scale, but also must take into account personal weight history and other markers of disease risk, such as blood lipids and blood glucose. 4. Describe a practical method to define obesity in a clinical setting. (LO 7.3) Body mass index (BMI) – a ratio of weight to height – can be measured easily in the clinical setting with a scale and stadiometer. BMI is not a perfect predictor of excessive body fat, but it is a starting point for identifying people at risk for chronic diseases related to excess body fat. Using BMI, obesity is defined as ≥30 kg/m2. Some other methods, such as bioelectric impedance analysis, give a better assessment of actual body composition, but such methods are not always practical. 5. List three health problems that obese people typically face and a reason that each problem arises. (LO 7.3) People with obesity typically face many major chronic health problems, including type 2 diabetes, hypertension, heart disease, and stroke. Obesity is linked to insulin resistance, which causes blood glucose levels to rise. When fasting blood glucose exceeds 125 mg/dl, a person is diagnosed with diabetes. High blood glucose and high insulin levels contribute to cardiovascular disease. Abnormal blood lipid levels (high total cholesterol, triglycerides, and LDL; low HDL) promote atherosclerosis. As blood vessels become clogged with plaque, the blood supply to the heart and other vital organs decreases. This could lead to heart attack or stroke. Hypertension arises because of the additional miles of blood vessels required to support excess body tissue (both adipose and muscle). This places strain on the heart. Hardening of the arteries also reduces flexibility of blood vessel walls, which further increases blood pressure. 6. What are three key characteristics of a sound weight-loss program? (LO 7.5) A sound weight loss program should incorporate control of calorie intake, increased physical activity, and life-long behavior modification. Decreasing calorie intake and increasing physical activity create negative energy balance, which results in weight loss. To maintain changes over time and avoid weight regain, permanent behavior modification is required. 7. Why is the claim for quick, effortless weight loss by any method always misleading? (LO 7.5) A permanent weight loss is a lifestyle change, not a quick or effortless fix. Any weight loss that results quickly, as with some fad diets, is typically a loss of water weight, not fat. A pound of fat represents approximately 3500 kcal. In order to lose 10 pounds, a person must create a calorie deficit (through decreased food intake and/or increased physical activity) of 100 kcal per day and sustain that deficit over time. The full 10-pound weight loss would not be realized for three years. Contrary to the claims of fad diets, sustained weight loss requires effort and takes time. 8. Define the term behavior modification. Relate it to the terms stimulus control, self-monitoring, chain-breaking, relapse prevention, and cognitive restructuring. Give examples of each. (LO 7.8) Behavior modification represents taking control of problem behaviors. All of the following terms are discussed when employing behavior modification in a person with obesity. Stimulus control involves altering the environment to minimize the stimuli for eating. For example, removing foods from sight and storing them in kitchen cabinets minimizes the stimuli for eating. Self-monitoring describes the task of tracking foods eaten and conditions affecting eating; actions are usually recorded in a food diary, along with location, time, and state of mind. This tool helps people understand more about their eating habits. Chain-breaking refers to breaking the link between two or more behaviors that encourage overeating, such as snacking while watching television. Relapse prevention refers to strategies that help prevent or cope with weight-control lapses. For example, if a person is prone to gain a few pounds over the holidays, he or she could make specific plans to increase physical activity and limit calorie intake at holiday parties. Cognitive restructuring is changing one’s frame of mind regarding eating. Instead of using a difficult day as an excuse to overeat, one could substitute other pleasures for rewards, such as a relaxing walk with a friend. 9. Why should obesity treatment be viewed as a lifelong commitment rather than a short episode of weight loss? (LO 7.5) The treatment of obesity should be viewed as lifelong. If “problem” eating behaviors are only changed for a short amount of time, then as soon as the “problem” behaviors begin again, any weight lost will usually come back. 10. What steps are important to remember when an underweight person wants to gain muscle but not fat? (LO 7.10) A combination of diet and strength training is needed to gain weight as muscle. Strength training slows muscle loss that usually accompanies fat loss, builds the strength of muscles and connective tissues, and increases bone density. In terms of diet, a person should consume several meals and snacks throughout the day, fitting in extra calories to achieve weight gain. Focus on lean proteins, so that protein intake is near the upper end of the AMDR for protein (10% to 35% of total kcal). For fats, which are a dense source of kcal, use plant oils and nuts rather than loading up on solid fats, which are not the best for heart health. For carbohydrates, include lots of fruits, vegetables, and whole grains -- nutrient-dense, complex carbohydrates – rather than sweets and starchy snack foods. CHAPTER 8 1. Why is the risk of toxicity greater with the fat-soluble vitamins A and D than with water-soluble vitamins in general? (LO 8.1) Risk of toxicity is greater with fat-soluble vitamins (especially vitamins A and D) because they are not as readily excreted as water-soluble vitamins. Whereas excesses of water-soluble vitamins are excreted in the urine, fat-soluble vitamins accumulate in the liver and adipose tissue and can reach levels that are toxic to cells. 2. How would you determine which fruits and vegetables displayed in the produce section of your supermarket are likely to provide plenty of carotenoids? (LO 8.2) The fruits and vegetables that are orange, red, or dark green in color are likely to contain a lot of carotenoids. 3. What is the primary function of the vitamin D hormone? Which groups of people likely need to supplement their diets with vitamin D, and on what do you base your answer? (LO 8.3) The primary role of the vitamin D hormone is to regulate blood calcium levels. It regulates calcium absorption from the small intestine, calcium excretion by the kidneys, and the release of calcium from bone. People who receive inadequate sun exposure, such as those who live in cold climates, are homebound, or who cover their skin for religious or cultural reasons, may need to take vitamin D supplements. People who avoid dairy products, whether due milk allergies, lactose intolerance, or taste preferences, will likely require vitamin D supplementation, as dairy products are one of very few dietary sources of this vitamin. In addition, people with liver and kidney diseases may require vitamin D supplementation because they are unable to adequately convert vitamin D to its active form. 4. Describe how vitamin E functions as an antioxidant. (LO 8.4) Vitamin E donates electrons or hydrogen atoms to unstable free radicals in cell membranes, thereby protecting cell membranes from oxidative damage. 5. Milling (refining) grains removes which vitamins and minerals? Which of these are replaced during processing? (LO 8.6) Milling of grain products removes thiamin, riboflavin, niacin, vitamin B-6, vitamin E, iron, zinc, magnesium, and potassium. Mandatory enrichment and fortification of refined grain products only adds thiamin, riboflavin, niacin, folic acid, and iron. 6. What are the best food sources for thiamin? (LO 8.7) Major sources of thiamin include pork products, whole grains (wheat germ), ready-to-eat breakfast cereals, enriched grains and flour, green beans, milk, orange juice, organ meats, peanuts, dried beans, and seeds. 7. What are the signs of a riboflavin deficiency? (LO 8.8) Symptoms associated with riboflavin deficiency (ariboflavinosis) include inflammation of the mouth and tongue, dermatitis, cracking of tissue around the corners of the mouth (called cheilosis), various eye disorders, sensitivity to the sun, and confusion. 8. Describe the three signs of the niacin deficiency, pellagra. (LO 8.9) The symptoms of the disease are dementia, diarrhea, and dermatitis (especially on areas of skin exposed to the sun). Left untreated, death is the result. 9. Describe how the RDA, DV, and UL for vitamin B-6 should be used in everyday life. How do the RDA and DV for vitamin B-6 differ? (LO 8.10) The adult RDA for vitamin B-6 is 1.3 to 1.7 milligrams per day. The Daily Value used on food and supplement labels is 2 milligrams. The Upper Level for vitamin B-6 is 100 milligrams per day. It is important to meet the RDA on a regular basis because vitamin B-6 performs a vital role in protein metabolism. However, if too much vitamin B-6 is consumed, such that the Upper Level is exceeded, malfunctions of the nervous system may result. The Daily Value for vitamin B-6 is a generic guide used on food labels that can be used to gauge the vitamin B-6 content of a food as it relates to typical human needs. The Daily Value for vitamin B-6 is higher than the current RDA. 10. How is pantothenic acid involved in energy metabolism? (LO 8.11) Pantothenic acid is required for the synthesis of coenzyme A (CoA), a coenzyme in chemical reactions that allow the release of energy from carbohydrates, lipids, and protein. It also activates fatty acids so they can yield energy and is used in the initial steps of fatty-acid synthesis. 11. Why does the consumption of raw eggs lead to a biotin deficiency? (LO 8.11) Biotin’s bioavailability varies significantly among foods based on the food’s biotin-protein complex. In raw egg whites, biotin is bound to avidin, which inhibits absorption of the vitamin. Consuming many raw egg whites can eventually lead to biotin-deficiency disease. Cooking, however, denatures the protein avidin in eggs so it cannot bind biotin. 12. Why does FDA limit the amount of folate that may be included in supplements and fortified foods? (LO 8.12) The FDA limits the amount of folate that may be included in supplements and fortified foods because excess folate in the diet can mask a vitamin B-12 deficiency. 13. Is it necessary for North Americans to consume a great excess of vitamin C to avoid the possibility of deficiency? Do vitamin C intakes well above the RDA have any negative consequences? (LO 8.14) Vitamin C is a water-soluble vitamin, so it is not stored to any great extent and dietary excesses are excreted in the urine. The RDA for vitamin C is 90 milligrams per day for men or 75 milligrams per day for women. As dietary intake increases above the RDA, absorption of the vitamin decreases and urinary excretion increases. Thus, taking megadoses of vitamin C will not significantly affect blood levels of the vitamin. However, large doses can cause irritation to the GI tract or lead to kidney stones in people who are prone to kidney stones, so exceeding the UL (2000 milligrams per day) is not a healthy practice. 14. Why is choline not considered a vitamin? (LO 8.15) Choline has important biological functions and an absence of the compound results in deficiency symptoms. However, the body is able to synthesize choline, so it is not yet clear if dietary intake of choline is necessary. Researchers are still trying to determine whether endogenous synthesis of this compound is sufficient to meet biological requirements at all stages of the life cycle. CHAPTER 9 1. Approximately how much water do you need each day to stay healthy? Identify at least two situations that increase the need for water. Then list three sources of water in the average person’s diet. (LO 9.1) The average human needs about 2.7 to 3.7 liters (11 to 15 cups) of water per day to remain healthy. If the temperature of the environment is very hot and humid, a person needs more water to keep the body cool, and if an individual is on a high protein diet, he or she may need more water because of increased urine output. Three common sources of water include beverages (e.g., tap water and fruit juice) and nearly every food. Foods from the fruit (e.g., oranges and apples) and vegetable (e.g., lettuce and tomatoes) groups are particularly high in water. 2. Identify four factors that influence the bioavailability of minerals from food. (LO 9.2) Some constituents of plant fibers may bind to minerals and reduce their bioavailability. Two examples of such compounds include phytate (phytic acid) and oxalate (oxalic acid), which limit the bioavailability of zinc and calcium, respectively. Consuming large doses of one mineral can reduce the absorption of another mineral. For example, excess zinc can reduce the absorption of copper. Absorption of some minerals, such as iron and calcium, may decrease with age. Also, absorption efficiency of some minerals varies based on body needs. For example, during pregnancy, when extra calcium is needed for fetal growth, absorption efficiency of calcium increases. 3. What is the relationship between sodium and water balance, and how is that relationship monitored as well as maintained in the body? (LO 9.3) Sodium is the major positive ion in extracellular fluid and a key factor in retention of body water. Fluid balance throughout the body depends partly on the concentration of sodium and other ions throughout the water-containing compartments of the body. Cells can actively pump sodium across the cell membrane, and because water moves where sodium moves, the distribution of water across cell membranes can be controlled. Fluid balance in the body is controlled by hormones that primarily act on the kidneys to either retain or excrete sodium, and therefore water. 4. List three sources of dietary calcium. Identify two factors that negatively influence the absorption of calcium. Identify two factors that positively influence the absorption of calcium. (LO 9.6) A highly bioavailable dietary source of calcium is milk or milk products. Other animal sources include fish with bones (e.g., salmon). Grain products made with milk contribute calcium to the diet. Other plant sources of calcium include leafy greens, almonds, and some legumes. Some components of plant foods, including oxalic acid, phytic acid, and tannins, can bind to calcium and decrease its bioavailability. Age decreases calcium absorption due to lower acid production in the stomach and lower vitamin D activity. Vitamin D deficiency lowers calcium absorption. Diarrhea, whether acute or chronic, can decrease calcium absorption because food matter spends little time in contact with absorptive cells in the small intestine. Factors that enhance calcium absorption include the presence of lactose in the diet; blood levels of parathyroid hormone and vitamin D; slow movement of food matter through the gastrointestinal tract; low pH of the stomach; and higher requirements, as during adolescence or pregnancy. 5. Describe two methods that can be used to assess bone density. What demographic groups should have bone density measured? (LO 9.6) Central dual energy x-ray absorptiometry (DEXA) is the most accurate test of bone mineral density for the whole body. When whole-body DEXA scans are not feasible, peripheral DEXA can be used to assess bone mineral density at specific sites (e.g., wrist or ankle). Other site-specific methods include quantitative ultrasound or peripheral quantitative computed tomography. These more portable, less expensive methods cannot be used to diagnose osteoporosis, but they can be used in screening to see who requires follow-up with central DEXA. People who should undergo DEXA tests for osteoporosis include women older than age 65; men older than age 70; younger men and postmenopausal women with risk factors; perimenopausal women with low body weight, a history of low-trauma fractures, or who use medications that deplete bone mass; any adults who have had a fracture after age 50; adults who use steroid medications for treatment of a disease (e.g., rheumatoid arthritis or Crohn’s disease); and anyone diagnosed with or being treated for osteoporosis. 6. List three roles of magnesium in the body. Identify two chronic diseases that may be affected by magnesium status. (LO 9.8) Magnesium provides structure to bone. It is a cofactor in more than 300 chemical reactions in the body, including those that derive energy from carbohydrates, proteins, and fats. It plays roles in nerve function and muscle contraction, such that a magnesium deficiency affects heart and skeletal muscle function. Magnesium is also necessary for the synthesis of many compounds, including DNA, protein, and the active form of vitamin D. Poor magnesium status may increase risk for high blood pressure and type 2 diabetes. 7. Describe the symptoms of iron-deficiency anemia and explain possible reasons why they occur. (LO 9.9) Symptoms of iron-deficiency anemia are related to decreased delivery of oxygen to body tissues. Iron is part of hemoglobin, the blood protein that transports oxygen throughout the body. Symptoms include pale skin, fatigue, shortness of breath, cold extremities, and inability to concentrate. Iron is also required for activity of various enzymes. When iron deficiency occurs in infancy and childhood, cognitive development, immune function, and growth are negatively affected because of iron’s role in enzyme activity. 8. What is the relationship between iodine, the thyroid gland, and energy metabolism? (LO 9.12) The thyroid gland actively accumulates and traps iodide from the bloodstream to support thyroid hormone synthesis. Thyroid hormones are synthesized using iodide and the amino acid tyrosine. Because these hormones help regulate metabolic rate and promote growth and development throughout the body, iodide adequacy is important for overall energy metabolism. 9. Describe the functions of fluoride in the body. List three sources of fluoride. (LO 9.14) Fluoride adds strength to bones and teeth, makes tooth enamel more resistant to the acid produced by oral bacteria, and also has an antibacterial effect on microorganisms that cause dental caries. The primary sources of fluoride are fluoridated water (whether natural or added to municipal water supplies) and topical dental products (e.g., toothpaste). Dietary sources include seafood, seaweed, and some types of tea. 10. Explain the function of chromium in carbohydrate metabolism. (LO 9.15) Chromium is required for glucose uptake into cells by enhancing the function of insulin. 11. List three dietary strategies to lower blood pressure. (LO 9.17) The first dietary strategy to lower blood pressure is weight loss, achieved by decreasing calorie intake and increasing physical activity. Weight loss should decrease insulin levels, which affect blood pressure, and also decrease the workload of the heart. Second, hypertension may be caused by excessive alcohol intake. If this is the case, decreasing alcohol intake to moderate levels or abstaining from alcohol altogether can decrease blood pressure. Third, modifying dietary intakes of certain minerals – decreased intakes of sodium and chloride along with increased intakes of potassium, calcium, and magnesium – can lower blood pressure. The Dietary Approaches to Stop Hypertension (DASH) diet restricts sodium and chloride intakes by reducing consumption of processed foods and increases intakes of potassium, calcium, and magnesium by incorporating more fruits, vegetables, legumes, nuts, whole grains, and low-fat or fat-free dairy products. Solution Manual for Wardlaw's Contemporary Nutrition Anne M. Smith , Angela L. Collene 9780078021374, 9781260092189