Measuring Up the DRIs

November 2003

The year 1941 marked a milestone in nutrition history — the birth of the first set of Recommended Dietary Allowances (RDAs). At the crossroads of the depression and the discovery of vitamins and the effect of their deficiencies, creators of the original RDAs hoped to place an understanding of recommended nutritional intakes within ordinary people’s grasps. Starting with a list of recommended intakes for calories, protein, iron, calcium, vitamins A, C and D, thiamin, riboflavin and niacin, the RDAs were revised 11 times over 50 years, but never lost sight of the original goal — to prevent deficiencies by providing recommended intakes for essential nutrients.

As the world came to grasp the importance of nutrition and health, and regular folks started talking of increasing their fiber and decreasing their saturated-fat intakes, the RDAs were forced to evolve from a set of standards to avoid deficiencies into an all-encompassing plan that factors nutrition’s role in reducing the risk of chronic diseases. Enter the Dietary Reference Intakes (DRIs).

The latest reports
In 1997, the Food and Nutrition Board of the Institute of Medicine (IOM) of the National Academy of Sciences, Washington, D.C., unveiled its answer to incorporating these lofty goals in the first DRI report, “Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride.”

Following in the wake of the first Dietary Reference Report came four additional reports on folate and other B vitamins, antioxidants (vitamins C, E, selenium and the carotenoids), micronutrients (vitamins A and K, and trace elements such as iron, iodine, etc.), and macronutrients (fat, fatty acids, protein, amino acids, carbohydrates, sugars, dietary fiber, and energy intake and expenditure). Three additional reports — electrolytes and water, bioactive compounds, and alcohol in health and disease — are slated for completion in the near future.

The reports differ vastly from the old RDA tables. They also toss new acronyms at readers, such as AI (Adequate Intake), EAR (Estimated Average Requirement) and UL (Tolerable Upper Intake Level), right beside the old stand-by term, RDA.

According to International Food and Information Council Foundation (IFIC), Washington, D.C., RDA is the average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all (97% to 98%) healthy individuals in a particular life stage and gender group. Adequate Intake (AI) is a recommended intake value based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of healthy people that are assumed to be adequate — used when an RDA cannot be determined. Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases. And Estimated Average Requirement (EAR) is a daily nutrient intake value that is estimated to meet the requirement of half of the healthy individuals in a life stage and gender group — used to assess dietary adequacy and as the basis for the RDA.

Some of the major highlights of the current DRIs include the establishment of RDAs for copper and molybdenum; ULs for micronutrients such as vitamin A, boron, copper, iodine, iron, manganese, molybdenum, nickel, vanadium and zinc; increased calcium recommendations; recommendations of at least 1 hour of physical activity per day; ranges for protein, fat and carbohydrate percentages rather than exact percentages of calories or grams; percentage of added-sugar intakes; and fiber-intake recommendations.

Much to professionals’ delight, the DRI reports sought to establish UL. Nutrient intake above the UL indicates a potential for increased risk of adverse effects. With so few studies dedicated to adverse effects of nutrient intake, the IOM could not determine ULs for all nutrients. The IOM suggests that consumers be careful about consuming nutrients without designated ULs at levels above the RDA or AI.

Designer DRIs
Another cause for anticipation is the IOM’s macronutrient distribution. “I am excited about the DRIs,” says Dawn Jackson, R.D., a Chicago-based American Dietetic Association (ADA) spokesperson, who uses the DRIs regularly to counsel her patients. “It takes into account modern research and chronic disease. The DRIs do not take the ‘one size fits all’ approach. With the broad ranges of carbohydrates, protein and fat, we can meet individual meal plans.”

The recommended DRIs of 45% to 65% of calories from carbohydrates, 20% to 35% of calories from fat, and 10% to 35% of calories from protein make it much easier to accommodate individual preferences for various diets, like the extremely popular high-protein diet.

But the DRIs have inherent comprehension problems. The fact that they have been published gradually in several reports, instead of in a neat fold-out chart, has left some people frazzled. According to the International Food Information Council (IFIC), Washington, D.C., focus-group research conducted with registered dietitians indicates that health professionals have many questions about how to use the DRI values. Some professionals are using the DRIs in unison with the old RDAs, resulting in inconsistency. The old term of RDA used to be the name for the entire list of values. Now, the “new” term RDA refers to one set of values within the DRIs. Some are using the old RDAs for some values, such as electrolytes, and then they’re using the DRIs for other values, like vitamins and macronutrients. This creates a problem, since the new DRIs have different values than the old RDAs. Oftentimes, this happens simply because professionals are not aware which reports have been published.

The DRI reports are much more comprehensive and exhaustive than the RDAs, with much confusion over terms like UL and AI. In the end, the DRI reports are not meant for the general public, and condensed versions are in the works. “Dietary Reference Intakes: Applications in Dietary Assessment” and “Dietary Reference Intakes: Applications in Dietary Planning” were published to help professionals translate these documents for consumers.

Eventually, the DRIs will filter into the food labels consumers read on shelves across the country. For now, companies are still required to use current FDA nutrition-labeling standards. A study is already in place to assess the rationale for nutrition labeling based on the DRIs. Someday, the DRIs also will be reflected in heavy-hitting consumer-education tools like the Dietary Guidelines and the Food Guide Pyramid. And all of us will finally speak the same language.

To download copies of the DRIs, visit the Institute of Medicine of the National Academies website at www.iom.edu.

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