Module 2
Learning Objectives:
1) Distinguish between Dietary Reference Intakes and the Daily Values.
2) Describe the RDA, AI, UL, EAR and AMDR.
3) Demonstrate how to read Nutrition Facts labels.
4) Discuss how foods are grouped in the USDA Food Guide.
5) Describe how the USDA Food Guide addresses the components of a healthy diet—adequacy, balance, calorie control, moderation, and variety.
6) Discuss how the USDA Food Guide can be applied to groups with different personal and religious food preferences.
7) Demonstrate how the United States Food Exchange System can facilitate calorie control.
8) Discuss the role of portion control in good nutrition. Nutrient Recommendations Nutrient recommendations are benchmarks by which healthcare practitioners, including dietitians, can evaluate an individual’s nutrient intake with their nutrient needs. Some nutrient recommendations also apply to populations of people rather than individuals. The Dietary Reference Intakes (DRI) is a SET of lists used to establish nutrient recommendations. The DRI includes the following tables: 1) Recommended Dietary Allowances (RDA). These are nutrient recommendations for individuals that group nutrient needs by age and sex. They are based on scientific research and concrete evidence.
2) Adequate Intakes (AI). These are also nutrient recommendations for individuals. The recommendations are grouped by age and sex just like the RDAs. However, they are really educated guesses. The research is evaluated to determine the recommendation, but the scientific evidence is just as concrete as it is for establishing RDAs.
3) Tolerable Upper Intake Levels (UL). This list identifies the upper limit of nutrient intake that is considered safe and without risk of even marginal toxicity. It is applied to vitamin and mineral intake. This is an excellent list for individuals who take supplements. It confirms that there is a safety tolerance above and below the actual RDA for a certain nutrient and that an intake that is too far above OR too far below the RDA can be a concern. Some individuals erroneously believe that if they consume less than the RDA it is bad and so more must be better. These individuals may be harming themselves with excessive supplement intake. They would be wise to consult the UL for recommendations on maximum intakes for safety.
4) Estimated Average Requirements (EAR). This list is a summary of average nutrient intakes for populations of people. It is used primarily by researchers and policymakers. Applications for this list would be when the researcher wants to compare the nutrient intake of a research population with the estimated need for that same nutrient or when policymakers want to study the impact of fortification of a certain nutrient in the food supply.
5) Acceptable Macronutrient Distribution Ranges (AMDR). These are values that individuals can use to determine the part of the diet that should come from carbohydrate, fat, and protein. The AMDR suggest 45-65% calories from carbohydrate, 20-35% calories from fat, and 10-35% calories from protein. Recommendations are based on the advice of expert committee members with an interest in diet and health. They look at evidence from balance studies that measure nutrient intake and nutrient excretion. The difference is the amount of the nutrient actually used by the body. RDAs reflect the value that applies to about 97.5% of the population. Some individual may actually need more than the recommendation. However, the recommendations for EAR and the Estimated Energy Requirement (EER) are based on an average and reflect the mid-point of needs across the population. This is particularly important when speaking of the EER that defines kilocalorie needs. It is important to not “overfeed” the population, and so it does not make sense to set that value as high as those for RDAs. The bottom line is that values for RDAs are set higher to cover the needs of a larger percentage of a population than the values that are set for energy needs and/or the EAR. The goals of the DRI committee are to:
1) Set recommended intake values. This is done with the RDA and AI.
2) Facilitate nutrition research and policy. This is done with the EAR.
3) Establish safety guidelines for nutrient intake. This is done with the UL.
4) Prevent chronic disease. This is done with the AMDR.
Nutrition Facts Labels and Daily Values The Nutrition Facts label is the method manufacturers use to communicate nutritional information about their product to consumers. These labels incorporate Daily Values (DVs) to help consumers understand how to interpret the nutritional content of the food for their individual needs. Read and study the information at the following link to learn more about how to read the Nutrition Facts label. Use this information to help you better understand how to read labels at the grocery store or at home. http://www.cfsan.fda.gov/~dms/foodlab.html Diet Planning Tools and Diet Quality Americans can use the Dietary Guidelines for Americans to help plan a healthy diet, but the USDA Food Guide provides a complement to also help implement healthy diet planning. The USDA Food Guide divides foods into different food groups. They are fruits, vegetables, grains, meats/meat alternates, milk and milk products, oils, and solid fats/added sugars. Within each group, there are recommendations on the types of foods and the quantities of food that are best for the healthy diet. For example, the fruit and vegetable groups emphasize the use of fresh fruits and vegetables. The grain group emphasizes the use of whole grain products. Meat selections are best if they are leaner meats like chicken and fish or trimmed cuts of beef. Milk and milk products should be lower fat products. Oils should be heavier in monounsaturated fats and include more olive and canola oil. Solid fats and added sugars are to be limited. The USDA Food Guide is an example of what some nutrition professionals call a food group plan. There is a graphic of the USDA Food Guide in your textbook. How does an individual know how many calories they need each day and how many servings from each food group they are allowed? The number of kilocalories needed is based primarily on sex, age and activity level. There are tables in your textbook that outline averages for each sex, age, and activity level. Under those kilocalorie recommendations are suggestions for the number of servings from each food group. The visual representation of the USDA Food Guide is MyPyramid. It is the latest version of the Food Guide Pyramid that individuals have used for years. MyPyramid was introduced in 2005 and is the new standard for how Americans should plan a healthy diet. You can see a visual representation of MyPyramid by visiting http://www.mypyramid.gov. The visual is dissected there to represent the different parts of the graphic. One area of note is the steps to the left side of the pyramid. Those steps with the silhouette walking up the steps is intended to link the message of physical activity from the Dietary Guidelines for Americans to the healthy diet messages they and the USDA Food Guide also convey. Your book illustrates graphics used by other ethnic groups and cultures to convey nutritional messages. Explore the following link to view USDA’s animation of MyPyramid: http://www.mypyramid.gov/global_nav/media_animation.html Be sure to have the volume turned up on your computer. This animation talks to you! USDA has also defined the concept of “discretionary calorie allowance.” This is the number of calories that remain that the end of the day if an individual has chosen healthy, nutrient-dense foods throughout the day and still has a calorie allowance to spare. For example, if an individual is allowed 2000 kilocalories per day and they manage to choose nutrient-dense foods during the day and meet their needs with only 1750 kilocalories actually consumed, then they can choose a food that is less nutrient-dense for the remaining 250 kilocalories their diet allows. It is like a reward to eating well earlier in the day. Individuals increase their discretionary calorie allowance by eating nutrient-dense foods that provide many vitamins and minerals for few calories and by exercising to burn off kilocalories from less nutrient-dense foods. Exercise also increases the basal metabolic rate making the impact of eating less nutrient-dense foods less significant than for someone who does not exercise at all. One key point about diet planning is portion control. Nutrient intake and kilocalorie intake are controlled by portion sizes. Look at the “Portion Distortion” slide presentation in this section of WebCT to compare how portion sizes have changed over the last 20 years. Consumers have come to expect larger portions even though they are distorted from the actual portion sizes that should be consumed. Portion distortion is a leading cause of malnutrition that results in obesity. Another method of diet management is the United States Food Exchange System (USFES). It can be used to control kilocalorie intake and/or carbohydrate intake. For this reason, it is particularly useful for weight management or management of diabetes. The appendices of the textbook feature the USFES. Notice that foods are grouped more specifically than with the USDA Food Guide. Carbohydrates are grouped as starches, fruit, and milk of a variety of fat contents. Other carbohydrates and non-starchy vegetables are also listed. For each specific group, there is a specific calorie per portion and number of carbohydrate per serving. The same is true with the meat/meat alternates that are shown in a range from very lean to high-fat and the fat group itself. An individual is assigned a meal pattern in the diet planning system. The meal pattern is designed to control calories, carbohydrates, or both. An example would be a 2,000 kilocalorie diet that allows for 9 servings of starch, 6 servings of lean meat, 5 servings of vegetable, 4 servings of fruit, 3 servings of fat-free milk, and 7 servings of fat. An individual can then look at the starch list and choose any food from that list, in the portion size shown, up to the total of 9 servings per day they are allowed. The same applies to other food groups.
Professor Cohan