Dear Reader,

RDAs (Recommended Dietary Allowances), prepared by the Food and Nutrition Board of the National Academy of Sciences, have been around for over 50 years, with periodic updates. The RDA is the average daily dietary intake level that would adequately meet the nutritional needs of nearly all (98 percent) healthy persons. RDAs include nutrients for which there is sufficient scientific evidence that they are required for good health. Their intention has always been to establish "standards to serve as a goal for good nutrition." RDAs provide the basis for evaluating the adequacy of diets of population groups. They are set at a level that includes a safety factor appropriate to each nutrient; so, this level actually exceeds the requirement for most individuals.

Currently, the Food and Nutrition Board is establishing Dietary Reference Intakes (DRIs). In addition to RDAs, DRIs will include recommendations for food components for which RDAs cannot be established. Some of these include fat, carbohydrate, fiber, and plant estrogens, among others. DRIs will also include maximum intake levels. Three dietary intake reference values for DRIs are:

Adequate Intake

The dietary intake level that would adequately sustain health when an RDA cannot be determined because of insufficient scientific evidence.

Estimated Average Requirement

The estimated dietary intake level that would maintain the health of half of a specified age and sex group.

Tolerable Upper Intake Level

The maximum level of daily nutrient intake that's apparently safe and unlikely to cause negative health effects in most healthy individuals.

DRIs and RDAs are NOT developed for specific individuals, but are for the making of policies for feeding programs, food labeling, and food fortification. The numbers signify levels of each compound that are appropriate for most healthy people in each category.

To access information on RDAs and DRIs, check out the Dietary Guidelines for Americans at the Food and Nutrition Information Center (FNIC) web site of the U.S. Department of Agriculture (USDA). (You need Adobe Acrobat to access this info.)

Vitamin supplements may contain an amount equivalent to the RDA, but you'll probably not find a supplement with every imaginable nutrient. There are innumerable substances that keep us healthy, many of which cannot be found in a pill. New aspects about how these function continue to be discovered. Alice emphasizes the importance of obtaining our nutrients from food. Concentrating on food first provides the balance that nature intended for us.

For more information, go to the The Institute of Medicine's web site.

Alice

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