Glossary: Dietary Reference Intakes

Dietary Reference Intakes

What is it?

After more than half a century, we may be seeing the end of the RECOMMENDED DAILY ALLOWANCES (RDAs) as we know them. On August 13, 1997, the U.S. National Academy of Sciences released the first in a series of new nutritional recommendations called Dietary Reference Intakes (DRIs). Although the first report covered only CALCIUM, PHOSPHORUS, MAGNESIUM, VITAMIN D and FLUORIDE, at least six more reports updating other nutrients are expected to follow over the next couple of years.

Nutrition experts agree that the RDAs were due for a major overhaul. "The RDAs, when first developed, were designed to meet the nutritional needs of almost all healthy people," explains Allison Yates, Ph.D., director of the Food and Nutrition Board (www2.nas.edu/fnb/) that oversees the RDAs. "They were meant to prevent nutritional deficiencies in planning diets for groups," says Dr. Yates. The fact that they've been used for everything from food labelling to nutritional analysis was more a function of convenience than science.

Times have changed. "Our understanding of the relationship between nutrition and chronic disease has progressed," says Vernon Young, Ph.D., chair of the committee overseeing the new DRIs. "We can now begin to recommend intakes that are thought to help people achieve good health."

The new DRIs are four separate recommendations, each of which addresses a different nutritional issue. They are:

Recommended Dietary Allowance (RDA): Unlike their predecessors, these RDAs recommend the amount of nutrient that will meet the need of almost every healthy person in a specific age and gender group (such as 19- to 30-year-old women). Also, these RDAs are meant for use by individuals, and are designed to reduce disease risk, not just prevent deficiency.
Adequate Intake (AI): An interim RDA used when the scientific data isn't strong enough to come up with a final number, yet there is enough evidence to give a general guideline. Like the RDA, this number can be used by individuals in setting their personal dietary goals.
Estimated Average Requirement (EAR): The amount that will meet the estimated nutrient need of half of the people in a specific group (such as pregnant women under 18). It is meant for evaluating and planning the diets of large groups of people, like the army, not individuals.
Tolerable Upper Intake Level (UL): The maximum amount that a person can take without risking "adverse health effects." Anything above this amount might result in toxic reactions. In most cases, this number refers to total intake of the nutrient — from food, fortified foods and nutritional supplements.