The Science and Scope of Nutrition

The Science and Scope 1 of Nutrition

LEARNING OBJECTIVES

Define the scope and science of nutrition ( Infographic 1.1 ) Explain the connection between nutrition and chronic disease ( Infographic 1.2 ) Define and identify the major macronutrients and micronutrients ( Infographic 1.3 and Infographic 1.4 ) Summarize the purpose of the Dietary Reference Intake (DRI) values ( Infographic 1.5 ) Distinguish between the different types of DRI values and what each represents ( Infographic 1.6 and Infographic 1.7 ) Understand/explain the basis of the scientific method and how it is CHAPTER used in nutrition research ( Infographic 1.8 ) Describe three types of experimental design and the primary advantages of each ( Infographic 1.9 ) Describe reliable sources of nutrition information ( Infographic 1.10 )

t was the final months of World War ii, and the dutch people were starving. as a last-ditch effort to hold on to the netherlands, the Germans had blocked the transport of food SPL/Science Source SPL/Science i from the netherlands eastern rural areas to its west- exploring the ern cities. as a result, people were eating only a few hundred calories per day, typically a couple of small Science of slices of bread and potatoes. Some people used paper to thicken soup. This period, now known as the dutch hunger Winter, lasted from october 1944 Nutrition until the netherlands was liberated in May 1945.

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Thirty years later, a husband and wife it appeared as if a woman’s diet during preg- team of scientists at Columbia University nancy could have a strong influence on the decided to investigate whether these extreme weight of her child. nutritional conditions had any long-lasting Other research soon followed. In the late effects on the Dutch people. After examining 1980s, scientist David Barker, MD, PhD, found Dutch army records from 300,000 19-year-old that babies with low birth weight were more men born around the time of the famine, the likely to develop heart disease later in life—a researchers made a startling discovery. They finding that helped generate the “developmen- found that men were significantly more likely tal origins hypothesis,” which states that cer- to be obese if their mothers suffered famine tain diseases originate from conditions during during the first months of their pregnancy. pregnancy and infancy. Specifically, poor STAY TUNED For more on dietary However, men were less likely to be obese nutrition during that crucial time can perma- recommendations and if their mothers experienced starvation nently affect the way a baby’s body responds the impact of nutrition in the last months of their pregnancy and to food throughout his or her life. Subsequent during pregnancy, see into the first months of their son’s life. The Spotlight E. research has also shown that a woman’s diet explanation for this pattern wasn’t clear—but prior to conception and her body weight at conception affect the health of her baby. Prompted by these findings, nutrition scientists were asking many new questions about how food and nutrients affect the body. Could a mother’s nutrition have such Surviving World long-lasting effects on her unborn child? Are War II. An emaciated we not, as the common phrase states, what we Dutch boy, eat? —are we also what our mothers ate? And if Netherlands, circa so, how was this effect carried out in the body? 1944.

INTRODUCING THE SCIENCE OF NUTRITION These fascinating questions illustrate the importance and the relevance of the science of nutrition , which is an interdisciplinary science that studies factors that affect our food choices, the chemical and physiological processes involved in processing and deliver- ing the chemical components of those foods to cells throughout our body, and ultimately how those chemicals affect our health every NUTRITION day. ( INFOGRAPHIC 1.1) the study of dietary intake A lifetime of good health is a key reason and behavior as well as the to study the science of nutrition. We eat nutrients and constituents in food, including their use every day, and the substances we consume in the body and influence are broken down to fuel activity and to build on human health and support the body’s tissues. How can we fine-tune our food choices to optimize STAY TUNED health? How can we maintain strong bones Chapter 13 Nutrition and remain active and independent well into through the College Years provides a our later years? How do we reduce the risk of discussion of factors heart disease, eat to run a marathon, or sup- that influence eating port a growing baby during pregnancy? These behavior. questions and more are at the center of the

Hulton Archive/Getty Images Archive/Getty Hulton study of nutrition.

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INFOGRAPHIC 1.1 The Science of Nutrition The science of nutrition is fundamentally about how foods maintain health and influence the risk of disease.

NUTRIENTS chemical substances

OH present in food that are required for body function;

HO needed for metabolism, OH growth, development, Resveratrol reproduction, and tissue maintenance and repair FACTORS AFFECTING IDENTIFYING CHEMICAL AVAILABILITY AND CHOICES COMPONENTS OF FOOD ESSENTIAL NUTRIENTS nutrients that must be supplied through food because the body cannot Nutrition incorporates knowledge produce/synthesize attained from many sciences such as NUTRITION sufficient quantities to meet chemistry, physiology, agriculture, is the study of: its needs genetics, psychology, and geography, as well as economics, politics, and culture. CARBOHYDRATES compounds made up of carbon, hydrogen, and oxygen atoms that are EFFECTS OF FOOD ON ACTIONS OF FOOD found in foods as either HEALTH AND DISEASE RISK CHEMICALS ON THE BODY simple sugars or complex carbohydrates (starch and fiber)

Resveratrol PROTEINS large molecules that are assembled by joining − + together many amino acids—containing carbon, Decreases hydrogen, oxygen, and Inﬂammation nitrogen—into long chains LIPIDS organic compounds Adipose tissue composed of a diverse group of compounds that contain carbon-hydrogen What are several factors that affect your daily food choices? chains of varying length with a lower proportion ? of oxygen atoms than in Photo credit (top left): Roger Jegg - Fotodesign-Jegg.de/Shutterstock carbohydrates—fats are a subclass of lipids VITAMINS organic compounds that are required in small quantities FOOD PROVIDES NUTRIENTS be supplied through what we eat and drink for specific functions in the AND ENERGY because the body cannot produce them or body Nutrition scientists study food and the enough of them on its own. MINERALS inorganic individual components that make up food, including Six classes of nutrients are required for the chemical elements obtained nutrients . A nutrient is a chemical substance body to function: carbohydrates , proteins , through foods that are that is required for growth and to maintain lipids, vitamins, minerals , and water . What you essential in human nutrition proper body functioning. The body can eat, the specific quantity and variety of nutri- WATER an essential nutrient that produce many of its own nutrients, but other ents in foods, can promote health or increase has critical functions in the essential nutrients (such as vitamins) must your risk of disease. ( INFOGRAPHIC 1.2 ) body

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INFOGRAPHIC 1.2 Nutrition and Disease Risk

ISK INCRE SED R ASED REA RIS DEC K • Inﬂammation • Reproductive disorders • Tooth decay • Bowel disorders Decreased risk • Cardiovascular disease • Eye disorders of disease • Hypertension • Dementia • Birth defects and increased • Anemia • Osteoporosis • Infections longevity • Liver disease • Obesity • Diabetes • Cancer • Renal disease

Decrease Disease Risk Increase Disease Risk Diets that emphasize fruits Diets that lack fruits and and vegetables (especially colorful vegetables), whole vegetables, contain calories grains such as brown rice in excess of need, and and oats, low-fat dairy, include too much red and ﬁsh, and poultry are processed meats (bacon, health-promoting. Diets ham, and sausage) increase low in added salt, sugars, risk of disease. Processed solid and trans fats, and foods and reﬁned grains alcohol decrease risk such as white bread, added of disease. sugar, trans fats, salt, and alcohol also increase risk of disease. What we eat strongly aects our risk of disease and ultimately our risk of an early death.

LEADING CAUSES OF DEATH IN THE UNITED STATES (2015)

Heart disease Cancer Lower respiratory disease Accidents Stroke Alzheimer’s disease Diabetes Inﬂuenza and pneumonia

Kidney disease Cause of death signiﬁcantly inﬂuenced by diet Suicide

0 100 200 300 400 500 600 700 Number of Deaths for Leading Causes of Death (thousands) Source: Health, United States, 2016; Table 19

What three types of foods increase risk of disease when overconsumed, and what three types of foods increase risk of disease ? when underconsumed? Photo credits (all photos): Eli Ensor

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All six classes of nutrients regulate numer- All six nutrient categories. This colorful MACRONUTRIENTS ous body processes, and most supply the meal contains all six nutrient categories: a term used to describe nutrients that we require carbohydrates, lipids, proteins, vitamins, building blocks of key body structures such in relatively large as cell membranes, muscles, and bones. They minerals, and water. amounts (for example, are required for normal growth, development, carbohydrates, proteins, water, and lipids) reproduction, maintenance, repair of cells, and other vital body processes. Nutrients are divided into two major categories. The first is macronutrients , which we need in relatively large quantities to stay healthy—these are carbohydrates, proteins, lipids (fats, a common term for triglycerides, are a subclass of the diverse group of compounds called lipids), and water. ( INFOGRAPHIC 1.3) With the exception of Tooga/Getty Images Tooga/Getty

INFOGRAPHIC 1.3 The Macronutrients Carbohydrates, lipids, protein, and water are required in large amounts. With the exception of water, each of these nutrients provides energy.

The Macronutrients (required in large amounts)

Carbohydrates Lipids Proteins Water

Energy 4 kcal/g 9 kcal/g 4 kcal/g 0 Content

Structural Abundant in skin, cartilage, Components of the cell Major structural component Fills and surrounds Function ligaments, and other joint membrane, fat deposits of every cell and tissue in every cell tissue, sugars are a shape our body and provide our body component of DNA and RNA insulation and protection

Regulatory Critical source of energy for Required for synthesis of Regulates fluid balance and Controls body Function the brain and red blood cells, hormones and other facilitates chemical reactions temperature and is helps regulate bowel function compounds that regulate involved in many many body processes chemical reactions Nutrients are substances that are obtained from food and are required for normal growth, development, reproduction, Alcohol is not a nutrient—it is a toxin—but does supply energy 7 kcal/g maintenance, and repair of cells. ? Given that alcohol supplies energy, why is it not considered a nutrient? Photo credits (left to right): Maximilian Stock Ltd/age fotostock/Eli Ensor, DUSAN ZIDAR/Shutterstock, Dorling Kindersley/Getty Images, Maria Toutoudaki/Getty Images

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INFOGRAPHIC 1.4 Vitamins and Minerals: The Micronutrients

The Micronutrients (required in small amounts) Not a source of energy Vitamins Minerals Called micronutrients because they are needed Water Soluble Fat Soluble Major Minerals Trace Minerals in tiny amounts, these substances in animal and • Thiamin • Folate • Vitamin A • Calcium • Chromium • Iron plant foods are necessary • Niacin • Pantothenic acid • Vitamin E • Chloride • Copper • Manganese for proper growth and • Vitamin B • Vitamin B • Vitamin D • Magnesium • Fluoride • Molybdenum development; the 6 12 consequences of a • Vitamin C • Biotin • Vitamin K • Phosphorus • Iodine • Selenium micronutrient deﬁcit • Riboflavin • Choline • Potassium • Zinc can be profound. • Sodium • Sulfur

Function: Function: • Participate in nearly every chemical reaction in • Most cooperate with proteins to facilitate chemical the body reactions • Some function as hormones • Some participate in nerve impulse transmission and muscle contraction • Some provide body structure

? What is the energy content of vitamins? Of minerals?

water, macronutrients primarily supply as color, aroma, and flavor. The phytochemi- energy and/or a large portion of the structural cal lycopene, for example, gives tomatoes components in our body. and watermelon their red color and may ENERGY When we see calories listed on food labels, reduce the risk of cancer in humans. Some the capacity to do these are actually kilocalories (kcal) that phytochemicals promote health because work; obtained through reference the amount of energy in food. A they have hormonelike actions or they repair the breakdown of carbohydrates, proteins, kilocalorie is equal to 1000 calories. By con- or prevent damage to cells. Anthocyanins, and fats in foods and vention, when Calorie is spelled with a capital for instance, are phytochemicals that give beverages C, it also refers to a kilocalorie. The abbrevia- berries their blue or purple color and act as KILOCALORIES tion “kcal” will be used throughout this book antioxidants. (KCAL) when discussing specific amounts of energy. Macronutrients, micronutrients, and phy- a standard unit used to measure energy provided The second category of nutrients is tochemicals are extracted from food through by food micronutrients , which are needed in much the process of digestion (see Chapter 3 for MICRONUTRIENTS smaller amounts—these are vitamins and more on digestion) and then absorbed and a term used to describe minerals. Micronutrients do not supply energy used by the body. Nutrients play a critical role nutrients essential in our diet to maintain good or calories but even in tiny amounts are in maintaining homeostasis , the process by health but required in crucial to normal growth and development. which the body maintains a stable internal only small amounts (for (INFOGRAPHIC 1.4) environment in the face of external variabil- example, vitamins and Another important part of the diet is ity. For instance, nutrients in the foods we minerals) phytochemicals (also known as phytonu- eat participate in processes that regulate the PHYTOCHEMICALS compounds found in trients ), which are chemicals in plants that balance of fluids in the body, our pH, and our plant foods that are are beneficial to human health. Commonly body temperature. As long as cells get the physiologically active and found in vegetables, fruits, and whole grains, nutrients they require, all is well; when cells beneficial to human health; not considered essential these compounds—which number in the receive either inadequate or excess nutrients, nutrients thousands—give plants key properties such however, problems arise.

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Burgers, fried foods, and foods and beverages high in sugar. A high-calorie “Westernized” diet is typically low in nutrient-rich fruits, vegetables, whole grains, and fish. STAY TUNED For more on phytochemicals, their sources, and potential health benefits, see Spotlight C.

UNDERNUTRITION inadequate nourishment caused by insufficient dietary intake of one or more essential nutrients or

bitt24/Shutterstock.com poor absorption and/or use of nutrients in the body OVERNUTRITION WHAT IS MALNUTRITION? diseases are now, by far, the leading causes excess intake or imbalance of calories and/or essential Both undernutrition and overnutrition are of mortality worldwide, and diet plays a nutrients relative to need forms of malnutrition —a state of inadequate specific role in the risk, progression, and that results in adverse or unbalanced nutrition. Sometimes treatment of nearly every chronic disease. health effects undernutrition does not stem from a lack In addition to providing many calories, the MALNUTRITION a state of undernutrition of food overall, but from a lack of specific highly processed foods common in our or overnutrition caused essential nutrients, known as nutrient “Westernized” diet are generally low in by inadequate, excessive, deficiency . nutrients such as fiber, potassium, calcium, or unbalanced intake of calories and/or essential Obesity , a condition characterized by and vitamin D that reduce the risk of chronic nutrients excess body fat and often associated with diseases. NUTRIENT other health problems, is a classic example DEFICIENCY of overnutrition. It’s a relatively new public NUTRIENT INTAKE a condition resulting from health concern. Historically, nutrition policy RECOMMENDATIONS insufficient supply of essential nutrients through and research focused on making sure people A question just as interesting as the role of dietary inadequacy or had enough to eat so that they could meet nutrition in early life is one you may impaired absorption or use their nutrient and energy needs. But over the frequently ask yourself: How do I know I’m OBESITY past few decades, policymakers have focused getting enough nutrients? To help us choose a condition characterized by accumulation of more on the role of diet and nutrition in dis- the foods that create a healthful diet, the excess body fat, generally eases caused by overconsumption—primarily Health and Medicine Division (formerly the associated with adverse too many calories along with too much solid Institute of Medicine) of the National Acade- health effects fat (such as animal fats), sugar, and sodium. mies of Sciences, Engineering, and Medicine— CHRONIC DISEASE Overconsumption is often associated with an expert committee commissioned by the a disease that is generally slow in progression and of chronic disease of slow progression, such as U.S. government—provides guidance on long duration (for example, heart disease and type 2 diabetes. Chronic health and science policy. The Health and heart disease and diabetes)

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DIETARY Medicine Division issues Dietary Reference values, the Recommended Dietary REFERENCE INTAKE Intake (DRI) values, which are quantitative Allowances (RDA) . (DRI) reference values for vitamins, estimates of nutrient intakes to be used to plan To create the RDA for a nutrient, a safety minerals, macronutrients, and assess diets for healthy people. These val- margin is added to the EAR so that the RDA and energy that are used to ues not only help us avoid nutrient deficiency represents the average daily amount of a assess and plan the diets of but also are intended to help individuals opti- particular nutrient that meets or exceeds the healthy people in the United States and Canada mize their health, prevent disease, and avoid requirements of nearly all (97–98%) healthy ESTIMATED consuming too much of any one nutrient. individuals. It is important to recognize that AVERAGE The DRIs for nutrients include four val- we do not need to meet the RDAs each day and REQUIREMENT ues. ( INFOGRAPHIC 1.5) Estimated Average that it is normal for our nutrient intake to be (EAR) the average nutrient intake Requirements (EARs) capture the average highly variable from one day to the next. Con- level estimated to meet the amount of a nutrient needed by people, suming an adequate, balanced, and varied diet daily requirements of half grouped by sex and age, in general. As such, each day will allow our average daily intake of the healthy individuals, this is an intake that meets the nutritional to meet the RDAs over the course of several according to sex and life stage (age) requirements of 50% of individuals within a days. During brief periods of inadequate RECOMMENDED group. Therefore, EARs are not recommenda- intake, our bodies will tap into nutrient stores DIETARY tions for individuals, as half of the population to meet immediate needs. In some cases, we ALLOWANCE (RDA) would be eating less than they need at this will respond to longer periods of low nutrient the recommended nutrient intake levels that meet the level of intake. Rather, the EARs are used to intake by increasing nutrient absorption and/ daily needs and decrease assess the nutrient adequacy of populations or decreasing their excretion to help maintain risks of chronic disease in and are the first step in setting another set of an adequate supply of essential nutrients. almost all healthy people for different sexes and life-stage groups

INFOGRAPHIC 1.5 The Dietary Reference Intake (DRI) values have varied purposes

Used to ensure adequate intake of a nutrient in an individual DRI values are used to assess the nutritional adequacy of individuals Recommended Dietary as well as populations. Allowance RDA

Tolerable Adequate Used to assess Upper Used to assess Intake the likelihood of Intake nutrient adequacy nutrient excess when no RDA is set UL AI

Estimated Average Requirement EAR

Determines the likelihood that nutrient intake is adequate in a population ? What DRI value provides information to help us avoid excess consumption of nutrients? Reprinted with permission from the National Academies Press. Copyright 2015, National Academy of Sciences

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INFOGRAPHIC 1.6 DRI Values Decoded The DRI values provide recommendations for nutrient intake needed to meet our body’s needs and reduce our risk of chronic disease. They are also meant to help us avoid consuming excess nutrients.

DIETARY REFERENCE INTAKES (DRI)

DRI Values for Most Nutrients

Reference Value Description When Planning Your Diet

Recommended Dietary The nutrient intake that is sucient to meet the needs of nearly all Goal for average daily Allowance (RDA) healthy individuals in a given age and sex intake over time

Adequate Intake (AI) Nutrients for which the available data are not sucient to conﬁdently Aim for this if an RDA determine an EAR (and thus an RDA). The AI is the best estimate of the isn’t available amount that is adequate to meet the needs of the majority of the population based on available data.

Estimated Average The nutrient intake that is estimated to meet the needs of 50% of healthy Do not use this amount Requirement (EAR) individuals in a given age and sex

Upper Limit (UL) The highest level of daily nutrient intake that is unlikely to cause adverse Do not exceed this amount eects for nearly all individuals in the population from all sources, including fortiﬁed foods, supplements, and prescription drugs

Additional DRI Values for Energy and Macronutrients

Reference Value Description When Planning Your Diet

Acceptable Macronutrient Intake ranges for energy-yielding macronutrients that are consistent Follow these guidelines for Distribution Range (AMDR) with good health, expressed as a percent of total calories the percent of calories from carbohydrates, fat, and protein

Estimated Energy The average energy intake predicted to maintain current body weight in a Use cautiously as an initial Requirement (EER) healthy adult of a speciﬁc age, sex, weight, height, and activity level. Fifty planning goal only percent of individuals will have energy needs higher or lower than this value.

? What three DRI values provide recommendations for nutrient intake that we should strive to achieve?

When there is insufficient evidence to These represent the highest amount of a spe- generate an EAR for a nutrient, the RDA for cific nutrient that most people can consume STAY TUNED Chapter 2 further that nutrient cannot be set and the commit- daily without causing any harm. As research addresses the compo- tee establishes yet another set of values: the evolves, existing DRI values are modified, nents of a healthy diet. Adequate Intake (AI) value, which is based and new ones for additional nutrients are on research or observations of the amount created. DRI values have been set for ADEQUATE of the nutrient healthy individuals typically macronutrients, micronutrients, and water. INTAKE (AI) consume. For example, the B vitamin called ( INFOGRAPHIC 1.6) the estimated value for folate has an established RDA, but the recom- Putting these all together creates a more recommended daily nutrient intake level used when there mended intake for biotin, another B vitamin, complete picture of each nutrient. For exam- is insufficient evidence to is currently provided as an AI. ple, for adult women and men, the EAR for determine a specific RDA Because store shelves are overflowing vitamin A is 500 micrograms per day (mcg/ TOLERABLE UPPER with food and supplements that supply day) and 625 mcg/day, respectively; the RDA INTAKE LEVEL (UL) extra amounts of nutrients, the DRI also sets is 700 mcg/day and 900 mcg/day, respectively; the maximum amount of nutrient allowed that has safe limits of nutrients with its set of values and the UL is 3000 mcg/day for both sexes. been proven to have no risk known as Tolerable Upper Intake Levels (ULs) . Deficiency or excess of vitamin A can injure of side effects

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INFOGRAPHIC 1.7 Adequate and Safe, or Not? When the intake of a nutrient falls between the RDA and the UL (in green portion of the graph), it is highly likely that intake is both adequate and safe.

Increasing Risk of Increasing Risk Inadequacy Adequate and Safe of Toxicity 100% 100% Marginal intake AI values will EAR generally fall As nutrient within this range. intake drops below RDA UL the RDA or rises AI above the UL, the 50% 50% risk of malnutrition increases. Risk of Adverse Effects Risk of Adverse Effects Risk of Adverse

0% 0%

Low Nutrient Intake High ? What are the two causes of malnutrition shown in this figure?

the human body. Deficiency impairs immune Adults can obtain adequate amounts of function and leads to night blindness and macronutrients when their carbohydrate eventually permanent blindness. At the other intake falls between 45% and 65% of total end of the spectrum, intakes of vitamin A calories, their protein intake falls between above the UL cause liver disease and can cause 10% and 35% of total calories, and their fat serious birth defects. ( INFOGRAPHIC 1.7) intake is within 20% and 35% of total calories. Individuals who regularly eat below or above ENERGY RECOMMENDATIONS these ranges put themselves at risk of getting Two recommendations about energy intake too few essential nutrients or of developing are also included in the DRI. Estimated chronic diseases. Energy Requirement (EER) is similarThe Micronutrientsto the (required in small amounts) EAR in that it represents the average amount of calories a healthy person of a particular Enough meat! The AMDRs have been set to age, sex, weight, height, and level of physical provide a healthy range of intakes for carbohydrates, activity needs in order to maintain his or protein, and total fat. ESTIMATED ENERGY REQUIREMENT (EER) her weight. This value meets the energy the estimated number of requirements of 50% of the population and calories per day required to actually exceeds the needs of nearly 50% of maintain energy equilibrium in a healthy adult; this value individuals. is dependent on age, sex, An imbalance in macronutrient intake height, weight, and level of (particularly of fat and carbohydrates) can physical activity increase the risk of several chronic diseases. ACCEPTABLE For this reason, the Acceptable Macronutrient MACRONUTRIENT DISTRIBUTION Distribution Ranges (AMDRs) have been RANGE (AMDR) established to provide a healthy range of the range of energy intakes intakes for carbohydrates, protein, and total that should come from each macronutrient to provide a fat (as well as some specific types of fat)

balanced diet expressed as a percentage of total calories. Olinchuk/Shutterstock

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But who knows how to use the DRI values Robert Waterland, PhD, epigenetics researcher to determine what they should eat each day? Given how difficult it can be to analyze individual diets, most people who use DRIs as a nutritional tool are researchers and registered dietitians. However, some publicly available computer programs and software applications can track meals and provide dietary information, making DRIs a tool that nonexperts can use too. In Chapter 2, we will further explore useful tools to guide food choice.

he DRI values vary depending on the Tspecific nutritional needs of different groups of people—children, adults, men, women, the elderly, and women who are and Pediatrics of Depts. Robert A. Waterland, Dr. Courtesy Medicine. of College Molecular & Human Genetics, Baylor pregnant or nursing. It is this last group that is often most concerned with getting all of babies were very little, to prevent them from the nutrition they need. This is something becoming obese later in life. “The first time Robert Waterland experienced firsthand while someone asked me, I didn’t think much of it,” working in his laboratory with renowned recalls Waterland. “But the second time, I got nutrition researcher Albert Stunkard. Water- intrigued.” land was studying physics in college when he He went to the library, scanned the sci- read a book that changed everything for him. entific literature, and discovered the Dutch It described how diet could boost athletic famine study. From then on, he was hooked performance (including marathon running, on how early nutrition—even in the womb— Waterland’s then-pastime). “I started think- could influence a child for life. “For me, that ing, ‘Wow, nutrition is really powerful, and study was the beginning. It just totally capti- has such an impact on health.’ That’s how I vated me—how is it possible that a person’s decided I wanted to study nutrition.” body can remember an exposure as a fetus During his time in Stunkard’s lab, Water- or infant, and have it affect their chances of land helped set up a research study of infants being overweight as an adult?” born to mothers who were either of healthy After working in Stunkard’s lab, Water- weight or obese. The mothers brought their land entered graduate school to continue babies into the laboratory, where Waterland studying the multigenerational effects of and his team spent the day measuring how nutrition. During that time, another study much food the babies consumed, checking on the subject was published that deepened their body composition, and even observing his interest even further. This study showed how they ate—their sucking style while that the diet of pregnant mice appeared to breastfeeding or bottle feeding, for instance. affect the coat colors of their young. Normally, The purpose, he says, was to see if any of when this strain of mice gives birth, the these variables measured in infancy would litter contains babies with coats in a range predict a baby’s likelihood of becoming obese of colors—some yellow, some brown, and all later in life. shades in between. The babies with yellow fur Because the mothers had to spend all day were more likely to eventually become obese in the lab, including even the babies’ nap and develop diseases, such as cancer, than times, they would sometimes sit down with their brown brothers and sisters. But when Waterland to chat. Over time, a few of the scientists fed pregnant mice supplements mothers who were obese asked him if there that contained a mix of folic acid, vitamin

was anything they could do now, when their B12, and other nutrients, mothers gave birth

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Waterland’s experimental mice. One mouse is pregnancy can have lifelong effects on their large and yellow-coated; the other is smaller and children. And interestingly, recent studies dark-coated. find that what fathers eat prior to conception can also have lifelong effects on their children. The field of genetics describes how genes encoded in DNA are passed on between gen- erations (from parents to child), but sometimes the DNA in our genes can become modified after it’s inherited, which can change traits in the current generation (as well as in subsequent ones). This explains why identical twins—who have the exact same genes—actually have slight differences in their appearance and risk of disease. This fascinating area of study that looks at the cross-generational effects of exposure to Republished with permission of Elsevier, from Journal of nutrients, toxins, and behaviors is called Pediatrics, 149, Waterland, R.A., Epigenetic mechanisms and gastrointestinal development, S137-S142, Copyright 2006. epigenetics. Waterland was interested in Permission conveyed through Copyright Clearance Center, Inc. epigenetics; he simply had to understand more about why a mother’s diet during preg- to fewer babies with yellow fur. “That caught nancy could affect the future health of her my attention,” recalls Waterland. To him, children. this study result was even more compelling evidence that what mothers eat during

Nutritional genomics. The study of how chemical compounds found in foods affect gene expression (the control of protein production as directed by our DNA) and how genes affect our individual responses to dietary factors and impact human health.

Photo credits: (veggies) ZoneCreative/Shutterstock, (fruit) maxpro/Shutterstock, (DNA) SARANS/Shutterstock

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INFOGRAPHIC 1.8 The Scientific Method Scientists follow these steps when pursuing the answers to scientific questions. The best conceived experiments typically generate new questions.

Begin with: OBSERVATION

The ﬁrst step in the scientiﬁc process is to make observations.

Peer Review and Publish ACCEPT HYPOTHESIS Result supports the The methods Reﬂect on Results Question hypothesis. and results are Ask New Questions reviewed by other Next, we can ask scientists working questions about the in the same area REJECT HYPOTHESIS observations we make. before the paper Result does not support Possible Compare Results is published. the hypothesis. Outcomes with Predictions

Theory versus Hypothesis: MODIFY HYPOTHESIS The results of many similar Testable Hypothesis studies must be consistent Result partially supports for a hypothesis to become the hypothesis. Experiment Propose a testable a theory. One experiment is explanation for the never sucient evidence to Develop an experiment observation, one that support a theory. to test your hypothesis. would help answer the question you asked.

? Explain why the following hypothesis is not suitable for the design of an experiment: "Dietary factors affect the risk of cancer."

NUTRITION SCIENCE IN ACTION the diet in pregnant mice affected an epigen- To begin his investigation, Waterland, like all etic mechanism called DNA methylation at the scientists, followed the scientific method. agouti gene, which controls coat color, so his ( INFOGRAPHIC 1.8) He started with an observa- hypothesis maintained that supplementing tion and then identified a question or problem the diet of pregnant mice with specific nutri- to investigate further. In his case, the obser- ents would increase the frequency of DNA vation that diet in pregnancy changed mouse methylation at agouti and therefore of the babies’ coat color and overall health led him to healthier brown-coated offspring. (Waterland wonder how that occurred. So he talked to his and others have found that the high intake of boss at the time, Randy Jirtle at Duke Univer- the nutrients used in this study can also have sity in North Carolina, and said he wanted to additional affects that are potentially harmful.) repeat the mouse study and try to understand the mechanism by which a mother’s nutrition Conducting an Experiment before and during pregnancy could change the Next, Waterland completed the experiment coat color of her offspring. stage of the scientific method. He repeated the mouse experiment, feeding some pregnant Forming a Hypothesis mice a supplemented diet, and obtained the Waterland came up with a testable hypoth- same results. Mothers who ate the extra nutri- SCIENTIFIC METHOD esis , which is a proposed explanation for an ents had more babies with brown fur, which a specific series of steps observation that can be tested through exper- previous research had found were at lower risk that involves a hypothesis, measurements and imentation. Based on the previous findings, of obesity and other diseases than those mice data gathering, and Waterland hypothesized that supplementing with yellow fur. After performing analyses interpretation of results

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of DNA methylation, he found that these dietary components in health and disease. epigenetic changes completely explained the (INFOGRAPHIC 1.9) effect of diet on coat color. “When I first saw those results that was when I felt just, ‘Wow, Analyzing the Results we really have something here.’” As a final step Because Waterland randomly assigned preg- in the scientific method, Waterland published nant mice to receive either the control diet his findings in a scientific journal. His find- or the supplemented diet and made sure the ings became another core source of evidence mice were the same in every other way, he supporting the effect of food on genes—a field could determine that the supplements caused known as nutritional genomics, or nutrigenomics. the change in the patterns of chemical modi- Waterland’s study contained many of the fication. Other studies, however, must rely on important elements of the scientific process. correlational evidence. For instance, if Water- It had a control group, a group of pregnant mice land had conducted a different study, with that received a healthy diet that did not contain human subjects, and asked mothers who had any extra supplementation. Waterland then already given birth to recall if they had taken compared the results from the control group a prenatal vitamin during their pregnancies with those from mice in the experimental or treat- and then he measured if there were any ment group, which received the supplemented epigenetic changes in their babies, he might diet, and he determined that the supplemented have seen a correlation, but he could never diet did produce important epigenetic changes. say whether the supplements caused any PLACEBO EFFECT In other studies, such as those that look epigenetic changes. For example, the mothers the apparent effect at the effect of medications, people in the who voluntarily choose to take a vitamin experienced by a patient control group receive a placebo drug, a sub- might also exercise more, drink more water, in response to a “fake” treatment due to the stance that contains no active properties. The or have a higher socioeconomic status—all of patient’s expectation of an purpose of the placebo is to eliminate the which could also cause epigenetic changes. effect placebo effect, a psychological phenomenon Although Waterland is quick to emphasize in which people feel better after receiving that the results of his experiment only apply a treatment simply because they have an to mice, it is now clear that epigenetic modifi- expectation that they will feel better, not cations are critical factors affecting the devel- necessarily because the treatment worked. opment of many human diseases. The mouse Therefore, their account of the actual effec- coat color experiment, along with the Dutch tiveness or ineffectiveness of a treatment is famine research, have “absolutely affected the unreliable. To eliminate the placebo effect, it way we think about nutrition,” says Patrick Sto- is critical that people do not know whether ver, PhD, director of the division of nutritional they are receiving the active treatment or the sciences at Cornell University. “Some people non-active placebo—in other words, they are seem to eat whatever they want and never gain blind to what they are receiving. By comparing weight. This has always been the case in nutri- people receiving a treatment with the pos- tion—people sometimes respond differently sibility of effect with those taking a placebo to the same foods. That cliché—we are what that has no possibility of effect, researchers we eat—has never really applied,” says Stover. can determine whether the treatment is actu- “We are just now beginning to understand ally effective, outside of people’s expectations. how genetic differences among individuals are Often, placebos are a key element of random- shaped by historical exposures, including food.” ized controlled trials (RCTs), which rigorously compare experimental interventions (such as CREDIBLE SOURCES OF NUTRITION a treatment) with controls (such as no treat- INFORMATION ment or administration of a placebo), and As new research emerges that challenges long- randomly assign people to each category to held theories, how do scientists know what offset any potential bias. In addition to RCTs, to trust? Often, they base their assessment epidemiological and animal studies also help of credibility on the strength of the evidence. us explore and evaluate the role of diet and Major factors that affect this evaluation are

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INFOGRAPHIC 1.9 Types of Nutrition Studies Many kinds of research are important in our understanding of the science of nutrition.

Randomized Controlled Trial Epidemiological Studies Experimental Model Systems

Subjects Randomly assigned

Experimental group Control group receives treatment. receives placebo.

HOW IT’S DONE HOW IT’S DONE HOW IT’S DONE Subjects are recruited and randomly assigned to an Epidemiological studies observe Animal experiments, cell culture studies, and experimental group and a control group. The the association between variables biochemical analyses are used as model experimental group receives the treatment while the in a population. However, they systems to understand how nutrients and other control group receives a placebo. When possible, the can never establish cause and chemical components of our diet aect subjects are blinded to the treatment they received. At eect relationships because physiological processes and their impact on the end of the study, data are collected and analyzed variables are neither manipulated health and disease. Much of what we know to determine whether the treatment altered the nor controlled—there is no about nutrients and the eects of diet on health outcome compared with those receiving the placebo. intervention. has been obtained from these types of studies.

BENEFIT BENEFIT BENEFIT Results are directly applicable to humans. Can assess complex interactions Can be performed when human studies would among genetic, behavioral, and be too costly, would be unethical, or would environmental factors. require an impractical length of time to complete.

An experimental protocol requires that a nutrient deficiency be induced to assess how this affects memory. What is the most ? appropriate study design to use to address this question? Photo credits (left to right): Image Source/Getty Images, Darren Baker/Shutterstock, Mark Harmel/Getty Images

the quality of individual studies, the number particular nutrient is good for cardiovascular DIETETICS of studies and the consistency of their results, health, whereas other sources argue the exact the application and communication of and the magnitude of the effect. A fundamental opposite. So to whom should you listen? knowledge concerned with principle of the scientific method is that similar Experts and educators in nutrition and the diet and its effects on results must be demonstrated multiple times dietetics have extensive training, often health, especially with the practical application of a through many studies before we can be confi- including clinical or research experience, scientific understanding of dent that similar cause-and-effect relationships that equip them to evaluate and translate nutrition have been identified. The stronger the evidence scientific information into dietary and health REGISTERED of a relationship between specific nutrients advice. One recognized food and nutrition DIETITIAN and disease risk or prevention, the more likely expert is the registered dietitian nutritionist , NUTRITIONIST a food and nutrition expert scientists are to recommend that people make or RDN (a new designation that expanded who has met the minimum changes to their diet as a result of the findings. upon RD, or registered dietitian, in 2013), who academic and professional Even nonexperts in nutrition today have relies on the research and recommendations requirements to qualify for the credential access to an unprecedented amount of of scientists in nutrition, biochemistry, med- information about the effect of nutrients icine, and the behavioral sciences to provide and food components on the body, genetic or scientifically valid nutrition information otherwise. Some sources may suggest that a and guidance to individuals and groups.

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Most RDNs work in hospitals and other health multiple peer-reviewed publications and has care facilities, perform research, have private the support of a group of experts in the field, practices, or have jobs in public health to help described sometimes as “scientific consen- prevent and treat disease. They belong to the sus.” Be wary of “.com” websites (which might Academy of Nutrition and Dietetics, the pro- be selling a product related to the nutrition fessional organization of Registered Dietitian “advice”), and turn mostly to sites that are Nutritionists. (“Nutritionists” are not always managed or reviewed by qualified health pro- RDNs—check the background and credentials fessionals. (INFOGRAPHIC 1.10) of people who call themselves nutritionists before seeking or following their advice.) HEALTH GOALS FOR AMERICANS RDNs are not the only source of credible Health professionals use data provided by nutrition information. Individuals who may government health agencies to understand not be RDNs but possess an advanced degree how effective nutrition and health programs in nutrition, nutritional biochemistry, or other are nationwide. Healthy People 2020, a related disciplines from accredited universities government-sponsored initiative, identifies can also be reliable sources of nutrition informa- measurable health improvement objectives tion. These individuals may work in universities and goals for Americans. Every decade the as faculty (often teaching the courses that future Healthy People initiative develops a new set RDNs take), government agencies, or research of science-based, 10-year national objectives institutions, and they carry out the research with the goal of improving the health of all that informs our understanding of the impact of Americans. The nutrition-related objectives nutrition on health and disease. recommend that we should consume a vari- According to the Academy of Nutrition and ety of nutrient-dense foods within and across Dietetics, most people obtain nutrition infor- different food groups, emphasizing whole mation from the Internet, from television, grains, fruits, vegetables, low-fat dairy prod- or from magazines. The most trustworthy ucts, and lean meats and other sources of sources provide evidence that stems from protein. Americans should eat only as many

Quick fix in a supplement? Phanie / Alamy Stock Photo Stock Phanie / Alamy

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INFOGRAPHIC 1.10 Credible Sources of Nutrition Information These agencies provide credible information because their positions rely on the results of peer-reviewed scientific publications and/or the consensus of many credentialed professionals (typically PhDs and MDs).

Government and Private Agencies/Credentialed Expert Advice Publications

Source Examples Source Examples

Nonprofit, Professional • American Heart Association Scientific, • Obesity Health Organizations • American Cancer Society Peer-reviewed • American Journal of Physiology: Endocrinology Journals • Academy of Nutrition and Dietetics and Metabolism • American Diabetic Association • Diabetes Care • American Institute for Cancer • American Journal of Clinical Nutrition Research • Annual Review of Nutrition • Journal of the Academy of Nutrition and Dietetics Scientific Organizations • National Academy of Science • Journal of Nutrition • American College of Sports Medicine • British Journal of Nutrition • The Obesity Society • Journal of the American College of Nutrition • Institute of Medicine (under National • Journal of the American Medical Association Academy of Science) • European Journal of Nutrition When searching the • Diabetes Government Publications: • National Institutes of Health Internet for reliable • Lancet Nutrition, Diet, and • Surgeon General information, you can limit • New England Journal of Medicine Health Reports your search to university • Food and Drug Administration • Journal of the American Medical Association and government websites • Journal of Clinical Investigation • Centers for Disease Control by entering site.edu or and Prevention site.gov, respectively. • Nature • United States Department of • Science Agriculture (USDA) Food and • Public Health Nutrition Nutrition Information Center • International Journal of Sports Nutrition and • USDA Center for Nutrition Exercise Metabolism Policy and Promotion • Medicine & Science in Sports & Exercise • NIH: National Center for Complementary and Alternative Medicine

Registered Dietitians • Hospitals Other • Tufts Health and Nutrition Letter • Public Health Departments (Although not peer- • Harvard Health Letter reviewed, these • Extension Service • Berkeley Wellness Letter publications rely on the expertise of the Other Nonproﬁt • Sense about Science faculty within each Organizations • HealthWatch-UK of these universities for their content.) ? Why are the three publications that are “letters” considered credible sources of information despite not being peer-reviewed?

calories as they need and limit their intake of Americans through the National Health and NATIONAL HEALTH saturated fats, trans fats, cholesterol, added Nutrition Examination Survey (NHANES) , AND NUTRITION EXAMINATION sugars, sodium (salt), and alcohol. Additional a program that collects data from individuals SURVEY (NHANES) information about the Healthy People initia- about their food and nutrient consump- an ongoing program of tive and updated goals for 2030 can be found tion and conducts physical examinations. studies that assess the health and nutritional status at www.healthypeople.gov . And the picture isn’t always pretty. of adults and children ( INFOGRAPHIC 1.11 ) across the United States by ASSESSING THE NORTH Although the U.S. food supply is abun- performing interviews and AMERICAN DIET dant, we are experiencing major shortfalls physical examinations. Unfortunately, the dietary goals set forth in in certain essential nutrients and excesses Healthy People 2020 don’t align with what in others. Approximately half of Americans many Americans eat. Over the years, the U.S. don’t get enough of the mineral magnesium, government has monitored the health of another 40% have low vitamin A intake,

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INFOGRAPHIC 1.11 National Health and Nutrition Examination Survey—NHANES examines a representative sample of about 5,000 persons across theacross the country each year. CDC Health Statistics for Center CDC/National

A health interview in the homes of the participants is Participants then report to Mobile Examination Centers the first step in the process. in their communities. J.L. Sousa/Newscom/ZUMA Press/ Sousa/Newscom/ZUMA J.L. Napa/California/USA Boston Globe/Getty Images Globe/Getty Boston

Dietary information is collected by conducting a Participants are physically examined by a variety of 24-hour diet recall survey. methods, including the collection of blood, urine, and DNA samples and data on body weight and height.

and another 35% are not getting enough hese nationwide data are very concerning vitamin C. Approximately 75% of Americans T to nutrition scientists, including Water- fail to consume enough fruit, and 85% or land, now an associate professor at the USDA/ more people consume inadequate amounts ARS Children’s Nutrition Research Center at of red, orange, and deep-green vegetables, Baylor College of Medicine. Although Water- and legumes. Snacks provide one-quarter land studies how a mother’s nutrition before of all daily calories, and many snack foods and during pregnancy affects the lifelong are high in empty calories (calories with few health of her child, he urges us to eat in nutrients)—namely, solid fats (butter, short- a way that promotes our own health and ening, fat in meat), added sugars (syrups well-being. Waterland explains: “The more and other caloric sweeteners), and refined variety of things you eat, the better, because starches. For adults and children older than there’s still so much that we don’t under- two years, nutrition surveys reveal that stand about nutrition. The safest bet is to eat approximately 85% of Americans signifi- a wide variety of foods, so you’re exposing cantly exceed recommended limits for these your body to all the potential benefits. Not empty calorie foods. Desserts and sweet just the epigenetic benefits, but others that snacks (such as cake, cookies, candy, and we know about, and still others we haven’t ice cream) account for the second-highest discovered yet.” source of total calorie consumption among all food group subcategories.

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CHAPTER 1 BRING IT HOME Evaluating sources of nutrition information The Internet is full of nutrition information—however, TAKE IT FURTHER not all of it is valid, useful, or accurate. Before you follow any nutrition advice, carefully evaluate the The Academy of Nutrition and Dietetics publishes source. position and practice papers on a variety of nutri- 1. On an Internet search engine, look up a nutrition tion topics related to health and disease. Accord- question that interests you. For example, “Do some ing to the Academy, a position paper is a “critical foods make you smarter?” “What are the best analysis of current facts, data and research liter- food sources of calcium?” Describe the article you ature that communicates the science on current selected. and emerging issues important to dietetics.” Visit www.eatright.org to learn more about the orga- 2. On what kind of website does the information nization and its position on various topics. Under appear? Is it a .com, .edu, or .gov? the “eatrightPro” tab on the home page, click 3. Is the author of the article listed? If not, can you on “Practice.” Scroll down to the “Position and determine who might have written it? Practice Papers” section, and click on “Position 4. Is there any evidence that the author of the infor- Papers.” After accessing this link, click on “Acad- mation has some authority in the field of nutrition emy Position Papers by Subject” and browse or health? What are the author’s qualifications, the list of position papers. Choose one, read the credentials, and connections to the subject? abstract, and skim the paper.

5. Who is the intended audience for this information? 1. What position paper was of interest to you Is the audience a scholarly one? If so, does the and why? article include a clear bibliography that you can 2. Was any other professional organization consult for further sources? involved in the development and publication 6. Are there clues that the author is biased? For of this position paper? If so, what example, is the author selling or promoting a organization(s) partnered with the Academy product? Is the author taking a personal stand on of Nutrition and Dietetics? a social or political issue? Describe how the article 3. List two or three pertinent facts or findings is biased, or provide evidence that it is unbiased. from the position paper abstract or article. 7. How timely is the information? When was the information published? 8. To verify the credibility of the source and better understand its intellectual value, search for additional articles on the topic where that same source or related sources are cited. Overall, does this appear to be a credible article? Explain.

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Nutrition science is an interdisciplinary field The DRI values are intended to help prevent that studies dietary intake and behavior, as nutrient deficiency, promote overall health, well as the nutrients and constituents in prevent disease, and avoid excess intake. To food, their use by the body, and their support these goals and provide more influence on human health. comprehensive nutrient recommendations, the DRI values encompass Estimated Nutrients are chemical substances obtained Average Requirements (EARs), from food that are required for normal Recommended Dietary Allowances (RDAs), growth, development, reproduction, and Adequate Intakes (AIs), and Tolerable Upper tissue maintenance and repair. They include Intake Levels (ULs). the macronutrients—carbohydrates, proteins, lipids, and water—and the micronutrients— The DRI values establish Acceptable vitamins and minerals. Macronutrient Distribution Ranges (AMDRs) for carbohydrates, proteins, and fats Phytochemicals are a dietary constituent expressed as a percent of total calories. found in plant foods that are beneficial to human health. Estimated Energy Requirements (EERs) are also established within the DRI values as Unbalanced nutrition, or malnutrition, can be average energy intakes needed to maintain the consequence of undernutrition, which weight in a healthy person of a particular may result in nutrient deficiencies, or age, sex, weight, height, and physical activity. overnutrition, which may result in accumulation of excess body fat or obesity. Nutrition research employs the scientific method. Research design and consistency Diet plays a significant role in the risk, across studies are important determinants of progression, and treatment of most chronic the quality, reliability, and applicability of diseases. Excess consumption of calories, study findings. animal fats, sugar, and sodium is linked to increased risk of the leading causes of Registered dietitian nutritionist (RDN) (also mortality. called RDs—registered dietitian) is the standard legal definition for someone having The Dietary Reference Intake (DRI) values extensive knowledge and training in foods, are issued by the Institute of Medicine and nutrition, and dietetics. provide quantitative estimates of recommended nutrient intake for individuals on the basis of sex, age, and life stage.

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Healthy People 2020 is a The health and diets of Americans are government-sponsored initiative that monitored through government surveys such provides science-based, ten-year national as the National Health and Nutrition objectives for improving the health of all Examination Survey (NHANES) that collects Americans. data about food and nutrient intake.

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1. Each of the six classes of nutrients: c. is to provide the amounts of nutrients required a. provide energy for the body. to restore health after major illness. b. are essential for growth, development, and d. is to meet the nutrient needs of nearly all reproduction. healthy people. c. are required in similar quantities by the body. 6. All of the following are true regarding the d. can be produced by the body if dietary intake is Adequate Intake (AI) value, EXCEPT: inadequate. a. it represents the average amount of calories 2. All of the following are true regarding allowed for maintenance of a healthy body phytochemicals, EXCEPT: weight. a. they are classified as an essential micronutrient. b. it represents the average daily amount of a nutrient that meets the needs of nearly all b. thousands of these compounds are found in healthy individuals. foods. c. it was established to meet the nutrient needs of c. they are linked to a reduced risk of cancer. 50% of a group of people based on age and sex. d. they are found primarily in plant foods. d. it was established when there was insufficient 3. Homeostasis can be defined as: evidence to generate an EAR for that nutrient. a. the process of digestion, absorption, and 7. The Tolerable Upper Intake Level (UL) is excretion of nutrients. defined as: b. the interaction of nutrients resulting in reduced a. the optimal level of nutrient intake a person absorption and utilization. should consume each day. c. the maintenance of a stable internal b. the estimate of a safe daily level of nutrient environment in the face of external variability. intake that should not be exceeded. d. the balance and distribution of carbohydrate, c. the amount of excessive intake consumed from protein, and fat intake in the overall diet. supplements and fortified foods.

4. Current nutrition research and policy focuses d. the level at which calorie intake exceeds primarily on: expenditure. a. diseases of overconsumption. 8. Randomized control trials encompass all of the b. nutrient deficiency diseases. following characteristics, EXCEPT: c. prevention of infectious diseases. a. they observe, without specific interventions, the d. dietary supplements and herbs. association between variables in a population. b. they compare the effects of an intervention 5. The focus of the RDA reference value: between experimental and control groups. a. is to only prevent deficiency diseases due to the c. they randomly assign people to receive or not prevalence of undernutrition. receive an intervention or a treatment. b. is on nutritional supplements rather than food d. they may incorporate a placebo to avoid the intake. expectation of results, or placebo effect.

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NEED TO KNOW

9. The name of the professional organization of c. a government-sponsored initiative that sets registered dietitians in the United States is the: goals and guidelines for the health of a. American Association of Dietitians and Americans. Nutritionists. d. a corporate and consumer partnership aimed at b. Academy of Nutrition and Dietetics. improving the healthfulness of commercial food products. c. American College of Dietetic Professionals. d. National Food and Nutrition Association.

10. Healthy People 2020 is: TAKE IT FURTHER a. an ongoing government survey that collects data on the intake and eating patterns of What are three speciﬁ c ways you can evaluate Americans. the credibility and scientiﬁ c validity of nutrition b. a public school-based program that translates information or claims in the media or on the the DRI values into food and exercise Internet? interventions.

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