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P A R T 1 INTRODUCTION TO BASIC PRINCIPLES OF NUTRITION SCIENCECHAP TE R 1Food, Nutrition, and HealthK E Y C O NCE PTS■ Optimal personal and community nutrition ■ Food and nutrient guides help us to plan a are major components of health promotion. balanced diet that is in accordance with our■ Certain nutrients in food are essential to our individual needs and goals. health and well-being.W e live in a world of rapidly changing elements, including our environ- ment, food supply, population, and scientiﬁc knowledge. Within dif- ferent environments, our bodies, emotional responses, needs, andgoals change. To be realistic within the concepts of change and balance, the studyof food, nutrition, and health care must focus on health promotion. Although wemay deﬁne health and disease in a variety of ways, the primary basis for promot-ing health and preventing disease must start with a balanced diet and the nutri-tion it provides. The study of nutrition is of primary importance in the followingtwo ways: it is fundamental for our own health, and it is essential for the healthand well-being of our patients and clients.HEALTH PROMOTION Health and WellnessBasic Deﬁnitions High-quality nutrition is essential to good health through- out life, beginning with prenatal life and continuingNutrition and Dietetics through old age. In its simplest terms, the word health isNutrition is the food people eat and how their bodies use defined as the absence of disease. However, life experi-it. Nutrition science comprises the body of scientific ence shows that the definition of health is much moreknowledge that governs food requirements for mainte- complex. It must include extensive attention to the rootsnance, growth, activity, reproduction, and lactation. of health for the meeting of basic needs (e.g., physical,Dietetics is the health profession responsible for applying mental, psychologic, and social well-being). This approachnutrition science to promote human health and treat recognizes the individual as a whole and relates health todisease. The registered dietitian (RD), who is also both internal and external environments. The concept ofreferred to as the clinical nutrition specialist or the public wellness broadens this approach one step further. Well-health nutritionist, is the nutrition authority on the health ness seeks the full development of potential for all peoplecare team; this health care professional carries the major within their given environments. It implies a balanceresponsibility of nutrition care for patients and clients. between activities and goals: work versus leisure, lifestylehttp://evolve.elsevier.com/Williams/basic/ 1
2 PART 1 Introduction to Basic Principles of Nutrition Sciencechoices versus health risks, and personal needs versus Importance of a Balanced Dietothers’ expectations. The term wellness implies a positivedynamic state that motivates a person to seek a higher Food and Healthlevel of functioning. Food is a necessity of life. However, many people are only concerned with food insofar as it relieves their hunger orNational Health Goals satisfies their appetite and not with whether it suppliesThe ongoing wellness movement continues to be a fun- their bodies with all of the components of proper nutri-damental response to the health care system’s emphasis tion. The six essential nutrients in human nutrition areon illness and disease and the rising costs of medical the following:care. Since the 1970s, holistic health and health promo- 1. Carbohydratestion have focused on lifestyle and personal choice when 2. Proteinsit comes to helping individuals and families develop 3. Fatsplans for maintaining health and wellness. The U.S. 4. Vitaminsnational health goals continue to reflect this wellness 5. Mineralsphilosophy. The most recent report in the Healthy People 6. Waterseries published by the U.S. Department of Health and The core practitioners of the health care team (i.e., physi-Human Services, Healthy People 2020, continues to focus cian, dietitian, and nurse) are all aware of the importanton the nation’s main objective of positive health promo- part that food plays in maintaining good health andtion and disease prevention1 (Figure 1-1). The guidelines recovering from illness. Therefore, assessing a patient’sencompass four overarching goals with the ultimate nutritional status and identifying his or her nutritionvision of a “society in which all people live long, healthy needs are primary activities in the development of alives.”1 health care plan. A major theme throughout the report is the encour-agement of healthy choices in diet, weight control, andother risk factors for disease, especially in the report’sspecific nutrition objectives. Community health agenciescontinue to implement these goals and objectives in local, health promotion the active engagement in behaviorsstate, public, and private health programs, particularly in or programs that advance positive well-being.areas where malnutrition and poverty exist. Programs nutrition the sum of the processes involved with thesuch as the Special Supplemental Nutrition Program for intake of nutrients as well as assimilating and usingWomen, Infants, and Children (WIC) and school lunch them to maintain body tissue and provide energy; aprograms are well established throughout the United foundation for life and health.States. Each effort recognizes personal nutrition as an nutrition science the body of science, developedintegral component of health and health care for all through controlled research, that relates to the pro-people. cesses involved in nutrition internationally, clinically, and in the community.Traditional and Preventive Approaches dietetics the management of the diet and the use ofto Health food; the science concerned with nutrition planningThe preventive approach to health involves identifying and the preparation of foods.risk factors that increase a person’s chances of developing registered dietitian (RD) a professional dietitiana particular health problem. Knowing these factors, accredited with an academic degree from an under-people can choose behaviors that will prevent or mini- graduate or graduate study program who has passedmize their risks for disease. Alternatively, the traditional required registration examinations administered byapproach to health only attempts change when symptoms the Commission on Dietetic Registration.of illness or disease already exist, at which point those health a state of optimal physical, mental, and socialwho are ill seek a physician to diagnose, treat, and “cure” well-being; relative freedom from disease orthe condition (see the Drug-Nutrient Interaction box, disability.“Introduction to Drug-Nutrient Interactions”). The tra- metabolism the sum of all chemical changes that takeditional approach has little value for lifelong positive place in the body by which it maintains itself andhealth. Major chronic problems (e.g., heart disease, produces energy for its functioning; products of thecancer, diabetes) may develop long before signs become various reactions are called metabolites.apparent.
CHAPTER 1 Food, Nutrition, and Health 3 Healthy People 2020 A society in which all people live long, healthy lives Overarching Goals: Determ inants • Attain high quality, longer lives Physical free of preventable disease, Figure 1-1 Healthy People 2020 Environment disability, injury, and premature Goals. (From the U.S. Department of Health death and Human Services. Healthy People 2020, Health Health Outcomes • Achieve health equity, eliminate Washington, DC: U.S. Government Printing Social Services disparities, and improve the Environment Ofﬁce; 2010.) health of all groups • Create social and physical Biology & environments that promote Individual Genetics good health for all Behavior • Promote quality of life, healthy development and healthy behaviors across all life stages DRUG-NUTRIENT INTERACTION INTRODUCTION TO DRUG-NUTRIENT INTERACTIONS Part of the traditional approach to medicine is “curing” the diminishing the effects of the intended medication. Dietary condition or disease. This often includes a physician’s supplements that contain vitamins and minerals can be prescription for a medication to alleviate symptoms or to especially dangerous if they are consumed at the same time treat the condition. Drug regimens should be strictly fol- as a drug. Knowing which drugs are inﬂuenced by nutrients lowed. Many medications have potentially dangerous side and how to work with a patient’s diet is essential to the effects, such as heart arrhythmias, hypertension, dizziness, development of a complete medical plan. and tingling in the hands and feet when they are consumed In the following chapters of this book, look for the Drug- inappropriately. Nutrient Interaction boxes to learn about some of the more Some medications may interact with nutrients in food or common interactions that may be encountered in the health dietary supplements, thereby creating a drug-nutrient inter- care setting. action. The presence of food in the stomach may increase Sara Harcourt or decrease drug absorption, thus potentially enhancing orSigns of Good Nutrition that life expectancy in the United States reached a high ofA lifetime of good nutrition is evidenced by a well- 75.4 years for men and 80.4 for women.2developed body, the ideal weight for height and bodycomposition (i.e., the ratio of muscle mass to fat mass), FUNCTIONS OF NUTRIENTSand good muscle development. In addition, a healthy per-son’s skin is smooth and clear, the hair is glossy, and the IN FOODeyes are clear and bright. Appetite, digestion, and elimina- To sustain life, the nutrients in foods must perform thetion are normal. Well-nourished people are more likely to following three basic functions within the body:be mentally and physically alert and to have a positive 1. Provide energyoutlook on life. They are also more able to resist infectious 2. Build tissuediseases as compared with undernourished people. This 3. Regulate metabolic processesis particularly important with our current trends of popu- Metabolism refers to the sum of all body processeslation growth and ever-increasing life expectancy. that accomplish the basic life-sustaining tasks. IntimateNational vital statistics reports published in 2010 stated metabolic relations exist among all nutrients and their
4 PART 1 Introduction to Basic Principles of Nutrition Sciencemetabolic products. This is the fundamental principle of % 35nutrient interaction, which involves two concepts. First, to %the individual nutrients have many specific metabolic 20 :functions, including primary and supporting roles. Fat CSecond, no nutrient ever works alone; this key principle ar boof nutrient interaction is demonstrated more clearly in hydra Carbohydratethe following chapters. Although the nutrients may be Fat te: 45% to 6separated for study purposes, remember that they do notexist that way in the human body. They always interact as Proteina dynamic whole to produce and maintain the body. 5%Energy Sources 5% 3 toCarbohydrates 0%Dietary carbohydrates (e.g., starches, sugars) provide the n: 1 teibody’s primary and preferred source of fuel for energy. P roThey also maintain the body’s backup store of quickenergy as glycogen (see Chapter 2). Human energy is Figure 1-2 The recommended intake of each energy-measured in heat units called kilocalories, which is abbre- yielding nutrient as a percentage of total energy intake.viated as kcalories or kcal (see Chapter 6). Each gram ofcarbohydrate consumed yields 4 kcal of body energy. Ina well-balanced diet, carbohydrates from all sources Tissue Buildingshould provide approximately 45% to 65% of the totalkilocalories. Proteins The primary function of protein is tissue building. DietaryFats protein provides amino acids, which are the buildingDietary fats from both animal and plant sources provide blocks that are necessary for constructing and repairingthe body’s secondary or storage form of energy. This form body tissues (e.g., organs, muscle, cells, blood proteins).is more concentrated, yielding 9 kcal for each gram con- Tissue building is a constant process that ensures thesumed. In a well balanced diet, fats should provide no growth and maintenance of a strong body structure asmore than 20% to 35% of the total kilocalories. Approxi- well as the creation of vital substances for cellularmately two thirds of this amount should be from plant functions.sources, which provide monounsaturated and polyun-saturated fats, and no more than 10% of kcals shouldcome from saturated fat (see Chapter 3).Proteins glycogen a polysaccharide; the main storage form of carbohydrate in the body, which is stored primarily inIdeally protein would not be used for energy by the body. the liver and to a lesser extent in muscle tissue.Rather, it should be preserved for other critical functions,such as structure, enzyme and hormone production, fluid kilocalorie the general term calorie refers to a unit ofbalance, and so on. However, in the event that necessary heat measure, and it is used alone to designate theenergy from carbohydrates and fat is insufficient, the body small calorie; the calorie that is used in nutrition science and the study of metabolism is the largemay draw from dietary or tissue protein to obtain required Calorie or kilocalorie, which avoids the use of largeenergy. When this occurs, protein yields 4 kcal per gram. numbers in calculations; a kilocalorie, which is com-In a well-balanced diet, protein should provide approxi- posed of 1000 calories, is the measure of heat that ismately 10% to 35% of the total kilocalories (see Chapter 4). necessary to raise the temperature of 1000 g (1 L) of Thus, the recommended intake of each energy-yielding water by 1° C.nutrient, as a percent of total calories, is as follows amino acids the nitrogen-bearing compounds that(Figure 1-2): form the structural units of protein; after digestion, ■ Carbohydrate: 45% to 65% amino acids are available for the synthesis of required ■ Fat: 20% to 35% proteins. ■ Protein: 10% to 35%
CHAPTER 1 Food, Nutrition, and Health 5Other Nutrients NUTRITIONAL STATESSeveral other nutrients contribute to the building andmaintenance of tissues. Optimal Nutrition Vitamins and Minerals. Vitamins and minerals are Optimal nutrition means that a person receives and usesnutrients that help to regulate many body processes. An substances obtained from a varied and balanced diet ofexample of the use of a vitamin in tissue building is that carbohydrates, fats, proteins, minerals, vitamins, andof vitamin C in developing collagen. Collagen is water in appropriate amounts. The desired amount ofthe protein found in fibrous tissues such as cartilage, each essential nutrient should be balanced to cover varia-bone matrix, skin, and tendons. Two major minerals, tions in health and disease and to provide reserve suppliescalcium and phosphorus, participate in building and without unnecessary excesses.maintaining bone tissue. Another example is the mineraliron, which contributes to building the oxygen carrierhemoglobin in red blood cells. Several other vitamins Malnutritionand minerals are discussed in greater detail in Chapters Malnutrition refers to a condition that is caused by an7 and 8 with regard to their functions, which include improper or insufficient diet. Both undernutrition andtissue building. overnutrition are forms of malnutrition. Dietary surveys Fatty Acids. Fatty acids, which are derived from fat have shown that approximately one third of the U.S.metabolism, help to build the central fat substance that is population lives on suboptimal diets. That does notnecessary in all cell membranes, and they promote the necessarily mean that all of these Americans are under-transport of fat-soluble nutrients throughout the body. nourished. Some people can maintain health on some- what less than the optimal amounts of various nutrients in a state of borderline nutrition. However, on average,Regulation and Control someone who is receiving less than the desired amountsThe multiple chemical processes in the body that are nec- of nutrients has a greater risk for physical illness andessary for providing energy and building tissue are care- compromised immunity as compared with someonefully regulated and controlled to maintain a constant who is receiving the appropriate amounts.3 Such nutri-dynamic balance among all body parts and processes. tionally deficient people are limited with regard to theirSeveral of these regulatory functions involve essential physical work capacity, immune system function, andnutrients. mental activity. They lack the nutritional reserves to meet any added physiologic or metabolic demands fromVitamins injury or illness or to sustain fetal development duringMany vitamins function as coenzyme factors, which are pregnancy or proper growth during childhood. Thiscomponents of cell enzymes, in the governing of chemical state may result from poor eating habits or a continu-reactions during metabolism. For example, this is true for ously stressful environment with little or no availablemost of the B-complex vitamins. food.Minerals UndernutritionMany minerals also serve as coenzyme factors with Signs of more serious malnutrition appear when nutri-enzymes in cell metabolism. For example, cobalt, which tional reserves are depleted and nutrient and energyis a central constituent of vitamin B12 (cobalamin), func- intake are not sufficient to meet day-to-day needs ortions with this vitamin in the synthesis of heme for hemo- added metabolic stress. Many malnourished people liveglobin formation. in conditions of poverty or illness. Such conditions influ- ence the health of all involved but especially that of theWater and Fiber most vulnerable populations: pregnant women, infants,Water and fiber also function as regulatory agents. In fact, children, and elderly adults. In the United States, whichwater is the fundamental agent for life itself, providing the is one of the wealthiest countries in the world, widespreadessential base for all metabolic processes. The adult body hunger and malnutrition among the poor still exist, whichis approximately 50% to 70% water. Dietary fiber helps to indicates that food security problems involve urbanregulate the passage of food material through the gastro- development issues, economic policies, and more generalintestinal tract, and it influences the absorption of poverty issues (see the Cultural Considerations box,nutrients. “Food Insecurity”).
6 PART 1 Introduction to Basic Principles of Nutrition Science CULTURAL CONSIDERATIONS FOOD INSECURITY Food insecurity is deﬁned by the U.S. Department of Agri- vascular risk factors such as hypertension and hyperlipid- culture as the limited or uncertain availability of nutritious emia among food-insecure adults.2 and adequate food. Using this deﬁnition, the Food Assis- Feeding America, which is the nation’s largest organization tance and Nutrition Research Program of the U.S. Depart- of emergency food providers, estimated that 14 million chil- ment of Agriculture reported that 17 million households dren in the United States receive emergency food services (i.e., 14.6% of all U.S. households) qualiﬁed as having food each year.3 Malnourished children are at an increased risk insecurity in 2008. Furthermore, homes with children report for stunted growth and episodes of infection and disease, double the rate of food insecurity as compared with homes which often have lasting effects on their intellectual develop- without children (21% and 11.3%, respectively).1 Many ment. Hunger is a chronic issue (i.e., persisting 8 months or studies document widespread hunger and malnutrition more per year) among most households that report food among the poor, especially among the growing number of insecurity. The prevalence of food insecurity is substantially homeless, including mothers with young children. Such higher among households that are headed by single mothers problems can manifest themselves as physical, psychologic, and in African-American and Hispanic households.1 A and sociofamilial disturbances in all age groups, with a variety of federal and nonfederal programs are available to signiﬁcant negative impact on health status (including address hunger issues in all cultural and age groups. The mental health) and the risk of chronic disease. Data from U.S. Department of Agriculture’s Food and Nutrition Service the National Health and Nutrition Examination Study provides detailed information about such programs on its (NHANES) demonstrated an increased incidence of cardio- Web site at www.fns.usda.gov/fns.1. Nord M, Andrews M, Carlson S. Household food security in the United States, 2008 (Economic research report 83). Alexandria, Va: U.S.Department of Agriculture, Economic Research Services; 2009.2. Seligman HK, Laraia BA, Kushel MB. Food insecurity is associated with chronic disease among low-income NHANES participants. J Nutr.2010;140:304-310.3. Mabli J, Cohen R, Potter F, Zhao Z. Hunger in America 2010; National Report Prepared for Feeding America. Chicago: Feeding America; 2010. Malnutrition sometimes occurs in hospitals as well. healthy population groups. Although these standards areFor example, acute trauma or chronic illness, especially similar in most countries, they vary according to the phi-among older people, places added stress on the body, and losophies of the scientists and practitioners with regardthe daily nutrient and energy intake may be insufficient to the purpose and use of such standards. In the Unitedto meet the needs of these patients. States, these standards are referred to as the Dietary Ref- erence Intakes (DRIs).OvernutritionSome people are in a state of overnutrition, which results U.S. Standards: Dietary Reference Intakesfrom excess nutrient and energy intake over time. Over- Since 1941, the Recommended Dietary Allowancesnutrition is another form of malnutrition, especially when (RDAs), which are published by the National Academyexcess caloric intake produces harmful body weight (i.e., of Sciences, have been the authoritative source for settingmorbid obesity; see Chapter 15). Harmful overnutrition standards for the minimum amounts of nutrients neces-can also occur among people who consistently use exces- sary to protect almost all people against the risk for nutri-sive (e.g., “megadose”) amounts of nutrient supplements, ent deficiency. The U.S. RDA standards were firstwhich can result in vitamin or mineral toxicities (see published during World War II as a guide for planningChapters 7 and 8). and obtaining food supplies for national defense and for providing population standards as a goal for good nutri- tion. These standards are revised and expanded every 5NUTRIENT AND FOOD GUIDES to 10 years to reflect increasing scientific knowledge andFOR HEALTH PROMOTION social concerns about nutrition and health. Both public awareness and research attention haveNutrient Standards shifted to reflect an increasing emphasis on nutrientMost of the developed countries of the world have estab- requirements for maintaining optimal health within thelished nutrient standard recommendations. These stan- general population as opposed to only preventing defi-dards serve as a reference for intake levels of the essential ciency. This change of emphasis resulted in the DRIsnutrients to meet the known nutrition needs of most project. The creation of the DRIs involved distinguished
CHAPTER 1 Food, Nutrition, and Health 7 Other StandardsBOX 1-1 DIETARY REFERENCE INTAKE Historically, Canadian and British standards have been PANELS OF THE INSTITUTE OF MEDICINE OF THE NATIONAL similar to the U.S. standards. In less-developed countries, ACADEMY OF SCIENCES where factors such as the quality of available protein foods must be considered, individuals look to standards such as 1. Calcium, vitamin D, phosphorous, magnesium, and those set by the Food and Agriculture Organization and ﬂuoride World Health Organization. Nonetheless, all standards 2. Folate and other B vitamins 3. Antioxidants provide a guideline to help health care workers who work 4. Macronutrients with a variety of population groups to promote good 5. Trace elements health and prevent disease through sound nutrition. 6. Electrolytes and waterU.S. and Canadian scientists, who were divided into six Food Guides and Recommendationsfunctional panels (Box 1-1) and who have examined To interpret and apply nutrient standards, health carethousands of nutrition studies addressing the health ben- workers need practical food guides to use for nutritionefits of nutrients and the hazards of consuming too much education and food planning with individuals and fami-of a nutrient. The working group of nutrition scientists lies. Such tools include the U.S. Department of Agricul-responsible for these standards forms the Food and Nutri- ture’s MyPlate system and the Dietary Guidelines fortion Board of the Institute of Medicine. The DRI recom- Americans.mendations were published over several years in a seriesof six volumes.4-9 MyPlate The DRIs include recommendations for each gender The MyPlate food guidance system (Figure 1-3), whichand age group as well as recommendations for pregnancy was released in June 2011 by the U.S. Department ofand lactation (see the inside front cover of this book). For Agriculture, provides the public with a valuable nutritionthe first time, excessive amounts of nutrients were identi- education tool. The goal of this food guide is to promotefied as tolerable upper intakes. The new DRIs incorporate variety, proportionality, moderation, gradual improve-and expand on the well-established RDAs. The DRIs ments, and physical activity.10 Participants are encouragedencompass the following four interconnected categories to personalize their own plans via the public Web siteof nutrient recommendations: www.choosemyplate.gov by entering their age, gender, 1. RDA. This is the daily intake of a nutrient that weight, height, and activity level. The system will create a meets the needs of almost all (i.e., 97.5%) healthy plan with individualized calorie levels and specific recom- individuals of a specific age and gender. Individuals mendations for serving amounts from each food group. should use the RDA as a guide to achieve adequate In addition, the MyPlate site provides participants with nutrient intake to decrease the risk of chronic individualized meal-tracking worksheets, tips, resources, disease. RDAs are established only when enough and sample menus as well as access to the Choose MyPlate scientific evidence exists about a specific nutrient. Tracker, an online dietary and physical activity assess- 2. Estimated Average Requirement. This is the intake ment tool. level that meets the needs of half of the individuals in a specific group. This quantity is used as the basis for the development of the RDA. Dietary Reference Intakes (DRIs) the nutrient recom- 3. Adequate Intake. The Adequate Intake is used as a mendations for each gender and age group that can guide when not enough scientific evidence is avail- be used for assessing and planning diets for healthy able to establish the RDA. Both the RDA and the populations. Adequate Intake may be used as goals for individual Recommended Dietary Allowances (RDAs) the recom- intake. mended daily allowances of nutrients and energy 4. Tolerable Upper Intake Level. This indicator is not a intake for population groups according to age and recommended intake. Rather, it sets the maximal gender with deﬁned weight and height. intake that is unlikely to pose adverse health risks MyPlate a visual pattern of the current basic ﬁve food in almost all healthy individuals. For most nutri- groups—grains, vegetables, fruits, dairy, and protein— ents, the Tolerable Upper Intake Level refers to the arranged on a plate to indicate proportionate daily intake from food, fortified food, and nutrient amounts of daily food choices. supplements combined.
10 tips choose MyPlate Nutrition Education Series 10 tips to a great plate Making food choices for a healthy lifestyle can be as simple as using these 10 Tips. Use the ideas in this list to balance your calories, to choose foods to eat more often, and to cut back on foods to eat less often. 1 6 balance calories switch to fat-free or Find out how many calories YOU need for a day low-fat (1%) milk as a first step in managing your weight. Go to They have the same amount of www.ChooseMyPlate.gov to find your calorie level. Being calcium and other essential nutrients as physically active also helps you balance calories. whole milk, but fewer calories and less 2 saturated fat. enjoy your food, but eat less 7 Take the time to fully enjoy make half your grains whole grains your food as you eat it. Eating To eat more whole grains, substitute a whole-grain too fast or when your attention is product for a refined product—such as eating whole- elsewhere may lead to eating too wheat bread instead of white bread or brown rice instead of many calories. Pay attention to hunger white rice. and fullness cues before, during, and after meals. Use 8 them to recognize when to eat and when you’ve had enough. foods to eat less often Cut back on foods high in solid fats, added sugars, 3 and salt. They include cakes, cookies, ice cream, avoid oversized portions candies, sweetened drinks, pizza, and fatty meats like ribs, Use a smaller plate, bowl, and glass. Portion out sausages, bacon, and hot dogs. Use these foods as foods before you eat. When eating out, choose a occasional treats, not everyday foods. smaller size option, share a dish, or take home part of 9 your meal. compare sodium in foods 4 Use the Nutrition Facts label foods to eat more often to choose lower sodium versions Eat more vegetables, fruits, whole grains, and fat-free of foods like soup, bread, and frozen or 1% milk and dairy products. These foods have the meals. Select canned foods labeled nutrients you need for health—including potassium, calcium, “low sodium,” ”reduced sodium,” or vitamin D, and fiber. Make them the “no salt added.” basis for meals and snacks. 5 make half your plate fruits and vegetables Choose red, orange, and dark-green vegetables like tomatoes, sweet potatoes, and broccoli, along with other 10 drink water instead of sugary drinks Cut calories by drinking water or unsweetened beverages. Soda, energy drinks, and sports drinks are a major source of added sugar, and calories, in American diets. vegetables for your meals. Add fruit to meals as part of main or side dishes or as dessert. DG TipSheet No. 1 June 2011 Center for Nutrition USDA is an equal opportunity Policy and Promotion Go to www.ChooseMyPlate.gov for more information. provider and employer.Figure 1-3 MyPlate food guidance system recommendations. (From the U.S. Department of Agriculture, Center for NutritionPolicy and Promotion. Choose MyPlate mini-poster (website): www.choosemyplate.gov. Accessed August 23, 2011.)
BALANCING CALORIES TO FOODS AND NUTRIENTS TO INCREASE MANAGE WEIGHT Individuals should meet the following Recommendations for specific population groups • Prevent and/or reduce overweight and obesity recommendations as part of a healthy eating through improved eating and physical activity Women capable of becoming pregnant 3 omen pattern while staying within their calorie needs. behaviors. • Choose foods that supply heme iron, which is • Increase vegetable and fruit intake. • Control total calorie intake to manage body more readily absorbed by the body, additional iron • Eat a variety of vegetables, especially dark-green sources, and enhancers of iron absorption such as weight. For people who are overweight or and red and orange vegetables and beans and peas. vitamin C-rich foods. obese, this will mean consuming fewer calories from foods and beverages. • Consume at least half of all grains as whole • Consume 400 micrograms (mcg) per day of • Increase physical activity and reduce time spent grains. Increase whole-grain intake by replacing synthetic folic acid (from fortified foods and/or refined grains with whole grains. supplements) in addition to food forms of folate in sedentary behaviors. from a varied diet.4 • Increase intake of fat-free or low-fat milk and • Maintain appropriate calorie balance during milk products, such as milk, yogurt, cheese, or each stage of life—childhood, adolescence, fortified soy beverages.2 Women who are pregnant or breastfeeding 3 adulthood, pregnancy and breastfeeding, and older age. • Choose a variety of protein foods, which include • Consume 8 to 12 ounces of seafood per week seafood, lean meat and poultry, eggs, beans and from a variety of seafood types. peas, soy products, and unsalted nuts and seeds. • Due to their high methyl mercury content, limit FOODS AND FOOD • Increase the amount and variety of seafood white (albacore) tuna to 6 ounces per week and COMPONENTS TO REDUCE consumed by choosing seafood in place of some do not eat the following four types of fish: tilefish, meat and poultry. shark, swordfish, and king mackerel. • Reduce daily sodium intake to less than 2,300 milligrams (mg) and further • Replace protein foods that are higher in solid • If pregnant, take an iron supplement, as reduce intake to 1,500 mg among persons who are 51 and older and those of any age who are African American or have hypertension, diabetes, or chronic fats with choices that are lower in solid fats and recommended by an obstetrician or other health kidney disease. The 1,500 mg recommendation applies to about half of the calories and/or are sources of oils. care provider. U.S. population, including children, and the majority of adults. • Use oils to replace solid fats where possible. Individuals ages 50 years and older • Consume less than 10 percent of calories from saturated fatty acids by • Choose foods that provide more potassium, replacing them with monounsaturated and polyunsaturated fatty acids. dietary fiber, calcium, and vitamin D, which are • Consume foods fortified with vitamin B12, such nutrients of concern in American diets. These as fortified cereals, or dietary supplements. • Consume less than 300 mg per day of dietary cholesterol. foods include vegetables, fruits, whole grains, and milk and milk products. • Keep trans fatty acid consumption as low as possible by limiting foods that contain synthetic sources of trans fats, such as partially hydrogenated oils, and by limiting other solid fats. BUILDING HEALTHY EATING PATTERNS • Reduce the intake of calories from solid fats and added sugars. • Select an eating pattern that meets nutrient needs over time at an appropriate • Limit the consumption of foods that contain refined grains, especially calorie level. refined grain foods that contain solid fats, added sugars, and sodium. CHAPTER 1 • Account for all foods and beverages consumed and assess how they fit within a • If alcohol is consumed, it should be consumed in moderation—up to one drink total healthy eating pattern. per day for women and two drinks per day for men—and only by adults of legal drinking age.1 • Follow food safety recommendations when preparing and eating foods to reduce the risk of foodborne illnesses. 51. See Chapter 3, Foods and Food Components to Reduce, for additional recommendations on alcohol consumption and speciﬁc population groups. Thereare many circumstances when people should not drink alcohol. 2. Fortiﬁed soy beverages have been marketed as “soymilk,” a product name consumers could see in supermarkets and consumer materials. However, FDA’s regulations do not contain provisions for the use of the term soymilk. Therefore, in this document, the term “fortiﬁed soy beverage” includes productsDIETARY GUIDELINES FOR AMERICANS, 2010 that may be marketed as soymilk. 3. Includes adolescent girls. 4. “Folic acid” is the synthetic form of the nutrient; whereas, “folate” is the form found naturally in foods. 5. Clean hands, food contact surfaces, and fruits and vegetables. Washing raw poultry, beef, pork, lamb, or veal before cooking it is not recommended. Bacteria in raw meat and poultry juices can be spread to other foods, utensils, and surfaces resulting in cross-contamination. DIETARY GUIDELINES FOR AMERICANS, 2010Figure 1-4 Summary of the Dietary Guidelines for Americans, 2010. (From the U.S. Department of Agriculture, U.S. Department of Health and Human Services. Dietary Food, Nutrition, and HealthGuidelines for Americans, 2010. Washington, DC: U.S. Government Printing Ofﬁce; 2010.) 9
10 PART 1 Introduction to Basic Principles of Nutrition Science after the Dietary Guidelines for Americans. This may seemDietary Guidelines for Americans a bit repetitive, but the difference is the added emphasisThe Dietary Guidelines for Americans were issued as a on the prevention of specific chronic diseases, such asresult of growing public concern that began in the 1960s heart disease and cancer.and the subsequent Senate investigations studying hungerand nutrition in the United States. These guidelines are Individual Needsbased on developing alarm about chronic health prob-lems in an aging population and a changing food environ- Person-Centered Carement. An updated statement is issued every 5 years, but Regardless of the type of food guide or recommendationsrecent review by expert committees has led to minimal used, health care professionals must remember that foodchanges over the past decade. This publication encom- patterns vary with individual needs, tastes, habits, livingpasses a comprehensive evaluation of the scientific evi- situations, and energy demands. People who eat nutri-dence regarding diet and health in a report jointly issued tionally balanced meals spread evenly throughout the dayby the U.S. Department of Agriculture and the U.S. can usually work more efficiently and sustain a more evenDepartment of Health and Human Services.11 energy supply. Figure 1-4 shows the four key recommendations of theDietary Guidelines for Americans. The current guidelines Changing Food Environmentcontinue to serve as a useful general guide for promoting Our food environment has been rapidly changing indietary and lifestyle choices that reduce the risk for recent years. American food habits may have deterioratedchronic disease. Although no guidelines can guarantee in some ways, with a heightened reliance on fast, pro-health or well-being and although people differ widely cessed, and prepackaged foods. Despite a plentiful foodwith regard to their food needs and preferences, these supply, surveys give evidence of malnutrition in all seg-general statements are meant to help evaluate food habits ments of the population. Nurses and other health careand move toward general improvements. Good food professionals have an important responsibility to observehabits that are based on moderation and variety can help patients’ food intake carefully. However, in general,to build healthy bodies. Americans are recognizing the relationship between food The current DRIs, MyPlate guidelines, and Dietary and health. Even fast-food restaurants are beginning toGuidelines for Americans are all in sync with one another respond to their customers’ desires for lower-fat, health-and supported by scientific literature, and they reflect conscious alternatives to the traditional fare. Other chain,sound guidelines for a healthy diet. family, and university restaurants are developing and testing similar patterns in their new menu items. MoreOther Recommendations than ever, Americans are being selective about what theyOrganizations such as the American Cancer Society and eat. Guided by the U.S. Food and Drug Administration’sthe American Heart Association also have their own nutrition labels, shoppers’ choices indicate an increasedindependent dietary guidelines. In most cases, the guide- awareness of nutritional values.lines set by various national organizations are modeled S U MM A RY■ Good food and key nutrients are essential to life and ■ Malnutrition exists in the United States in both over- health. nutrition and undernutrition states.■ In our changing world, an emphasis on health pro- ■ Food guides that help with the planning of an indi- motion and disease prevention by reducing health vidualized healthy diet include the DRIs, MyPlate, risks has become a primary health goal. and the Dietary Guidelines for Americans.■ The importance of a balanced diet for meeting this ■ A person-centered approach is best when developing goal via the functioning of its component nutrients individual dietary recommendations that take per- is fundamental. Functions of nutrients include pro- sonal factors into account. viding energy, building tissue, and regulating meta- bolic processes.
CHAPTER 1 Food, Nutrition, and Health 11 C R I T I C AL THINKING QU E STI O NS1. What is the current U.S. national health goal? Deﬁne regard to the following: (1) the main nutrients for each this goal in terms of health, wellness, and the differences function and (2) other contributing nutrients. between traditional and preventive approaches to health. 4. With regard to both purpose and use, compare the DRIs2. Why is a balanced diet important? List and describe with the MyPlate food guidelines. some signs of good nutrition. 5. Use the MyPlate guidelines to plan a day’s food pattern3. What are the three basic functions of foods and their for a selected person in accordance with the Dietary nutrients? Describe the general roles of nutrients with Guidelines for Americans. C H A P T ER CHAL L E NGE QU ES TI O NSTrue-False 2. True or False: The focus of the DRIs is to promote healthWrite the correct statement for each statement that is false. as opposed to exclusively centering on preventing disease.1. True or False: The diet-planning tool MyPlate is available 3. True or False: Malnutrition is not a problem in the United only to health care professionals. States.Multiple Choice1. Nutrients are a. chemical elements or compounds in foods that have 3. All people throughout life, as indicated by the DRIs, need speciﬁc metabolic functions within the body. a. the same nutrients in varying amounts. b. whole foods that are necessary for good health. b. the same amount of nutrients in any state of health. c. exclusively energy-yielding compounds. c. the same nutrients at any age in the same amounts. d. nourishing foods that are used to cure certain illnesses. d. different nutrients in varying amounts.2. All nutrients needed by the body a. must be obtained by speciﬁc food combinations. b. must be obtained by vitamin or mineral supplements. c. have only one function and use in the body. d. are supplied by a variety of foods in many different combinations. 6. Food and Nutrition Board, Institute of Medicine. Dietary Please refer to the Students’ Resource reference intakes for water, potassium, sodium, chloride,section of this text’s Evolve Web site for additional and sulfate. Washington, DC: National Academies Press;study resources. 2004. 7. Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for vitamin C, vitamin E, selenium, andREFERENCES carotenoids. Washington, DC: National Academies Press; 1. U.S. Department of Health and Human Services. Healthy 2000. people 2020. Washington, DC: U.S. Government Printing 8. Food and Nutrition Board, Institute of Medicine. Dietary Office; 2010. reference intakes for vitamin A, vitamin K, arsenic, boron, 2. Xu J, Kochanek KD, Murphy SL, Tejada-Vera B, Division of chromium, copper, iodine, iron, manganese, molybdenum, Vital Statistics. Deaths: final data for 2007. Hyattsville, Md: nickel, silicon, vanadium, and zinc. Washington, DC: National Center for Health Statistics; 2010. National Academies Press; 2001. 3. Hughes S, Kelly P. Interactions of malnutrition and immune 9. Food and Nutrition Board, Institute of Medicine. Dietary impairment, with specific reference to immunity against reference intakes for energy, carbohydrate, fiber, fat, fatty parasites. Parasite Immunol. 2006;28(11):577-588. acids, cholesterol, protein, and amino acids. Washington, 4. Food and Nutrition Board, Institute of Medicine. Dietary DC: National Academies Press; 2002. reference intakes for calcium, phosphorous, magnesium, 10. U.S. Department of Agriculture, Center for Nutrition Policy vitamin D, and fluoride. Washington, DC: National Acad- and Promotion. USDA’s myplate home page (website): emies Press; 1997. www.choosemyplate.gov. Accessed August 23, 2011. 5. Food and Nutrition Board, Institute of Medicine. Dietary 11. U.S. Department of Agriculture, U.S. Department of reference intakes for thiamin, riboflavin, niacin, vitamin B6, Health and Human Services. Dietary guidelines for folate, vitamin B12, pantothenic acid, biotin, and choline. Americans, 2010. Washington, DC: U.S. Government Washington, DC: National Academies Press; 2000. Printing Office; 2010.
12 PART 1 Introduction to Basic Principles of Nutrition ScienceFURTHER READING AND RESOURCES USDA Choose My Plate. www.choosemyplate.gov World Health Organization. www.who.intThe following organizations are key sources of up-to-dateinformation and research regarding nutrition. Each site Bachman JL, Reedy J, Subar AF, Krebs-Smith SM. Sources ofhas a unique focus and may be helpful for keeping abreast food group intakes among the US population, 2001-2002. J Am Diet Assoc. 2008;108(5):804-814.of current topics. Despite substantial research and efforts to make recommendationsAcademy of Nutrition and Dietetics. www.eatright.org known, Americans do not eat appropriate ratios of food from the recommended food groups. Instead, the average personAmerican Society for Nutrition. www.nutrition.org consumes excess fat and sugar throughout the day.Dietary Guidelines for Americans. www.health.gov/ Reedy J, Krebs-Smith SM. A comparison of food-based recom- dietaryguidelines mendations and nutrient values of three food guides: USDA’s mypyramid, NHLBI’s dietary approaches to stop hyperten-Food and Agriculture Organization of the United Nations. sion eating plan, and Harvard’s healthy eating pyramid. J Am www.fao.org Diet Assoc. 2008;108(3):522-528. The authors compare three food guide systems that are regularlyHealthy People 2020. http://healthypeople.gov/2020/ referred to in the United States. Although the research used forNational Research Council (National Academies of Science). the basis of each of the three guides varied, the general recom- http://sites.nationalacademies.org/NRC/index.htm mendations are the same.Society for Nutrition Education and Behavior. www.sne.org