Recommended Dietary Allowances
The Recommended Dietary Allowances (RDA) provide the essential-nutrient intake
levels required to meet the known nutritional needs of most (97-98%) healthy
persons in specific age and gender groups. The RDA is set two standard
deviations above the estimated mean requirement, and has been developed by the
Food and Nutrition Board of the National Academy of Sciences. The last RDA
released was in 1989.
Figure 6.1: Recommended Dietary Allowances (RDA), 1989
Dietary Reference Intakes
The RDA are currently under revision; values for certain nutrients have been
released periodically over the past few years. The new recommendations are
called Dietary Reference Intakes (DRI), and include four levels of values: 1)
Recommended Dietary Allowances (RDA); 2) Adequate Intakes (AI); 3) Tolerable
Upper Intake Level (UL); and 4) Estimated Average Requirement (EAR).
Recommended Dietary Allowances have the same meaning in the new revision as in
the previous version. The RDA are meant to be used as a goal for dietary intake
for individuals. The RDA are not necessarily intended to be used for assessing
the diets of individuals or groups, or planning for groups, although that is how
they are most often used. Table 2 provides 1998 RDA for those nutrients that
have revised values.
Figure 6.2: Recommended Dietary Allowances (RDA), 1998
Adequate intake values are set for nutrients for which no EAR has been set.
These values are based on observation or experimentation, and measure the
average intake of a population that appears to sustain a nutritional state such
as normal circulating nutrient values or growth. Table 3 below contains the AI
for those nutrients for which a value has been allotted.
Figure6.3: Adequate Intakes (AI), 1998
The Estimated Average Requirement is the nutrient-intake value that is estimated
to meet the requirement in 50% of the individuals in an age and gender group.
The EAR is used in setting the RDA. The EAR for selected nutrients is shown in
Table 4, below.
Figure6.4: Estimated Average Requirements (EAR), 2000
The Tolerable Upper Intake Level is the maximal level of nutrient intake that
will not pose risks of adverse health effects in most individuals. The UL do
not imply, however, that a beneficial effect will occur if that level of
nutrient is consumed.
Figure 6.5: Tolerable Upper Intake Levels (UL)
Dietary Guidelines for Americans
The Dietary Guidelines for Americans have been published every five years
since 1980 by the U.S. Department of Agriculture and Health and Human Services.
Their purpose is to provide the basis for federal nutrition policy and nutrition
education activities, and they offer advice as to food choices that promote
health and prevent disease in Americans ages two and older.
The 2000 Dietary Guidelines for Americans are:
1) Aim for Fitness:
Aim for a healthy weight
Be physically active each day
Let the food pyramid guide your food choices (see below)
2) Build a Healthy Base:
Choose a variety of grains daily, especially whole grains
Choose a variety of fruits and vegetables daily
Keep food safe to eat
3) Choose Sensibly:
Choose a diet that is low in saturated fat and cholesterol and moderate in
total fat
Choose beverages and foods to moderate your intake of sugars
Choose and prepare foods with less salt
If you drink alcoholic beverages, do so in moderation
Food Guide Pyramid
The Food Guide Pyramid was created by the U.S. Department of Agriculture
to help Americans choose foods from each food grouping. The focus of the
pyramid is on fat, which most Americans over-consume. The base of the pyramid
comprises foods that should be consumed in the greatest quantity; the top of the
pyramid comprises foods that should be consumed sparingly.
Starting from base to top, the food groups and number of servings that should be
consumed daily are as follows:
Breads, Cereal, Rice, Pasta: 6-11 servings
Vegetables: 3-5 servings
Fruit: 2-4 servings
Meat, Poultry, Fish, Beans, Eggs, Nuts: 2-3 servings
Milk, Yogurt, Cheese: 2-3 servings
Fats, Oils, Sweets: Use sparingly
Healthy People 2000
Healthy People 2000: National Health Promotion and Disease Prevention
Objectives is a national preventive strategy for improving the health of
Americans. The Secretary of Health and Human Services submits the guidelines to
Congress. Reports are compiled by the National Center for Health Statistics,
and the Centers for Disease Control. The guidelines have three major goals and
319 objectives. The three goals are: to increase the span of a healthy life; to
decrease health disparities; and to achieve access to preventive services for
everyone. One or more agencies of the U.S. Public Health Service are designated
to coordinate the activities.
