Good Nutrition Extends Beyond Rdas
Like home improvement do-it-yourselfers, many people are becoming home nutritionists.
Dietary supplements, organic foods and nutrition labels are hot topics. Determining how many grams of protein, fat and carbohydrates to eat each day can be complicated, not to mention getting enough vitamins and minerals.
The nutrition field is filled with confusing acronyms - RDA, DV, ESADDI - associated with guidelines designed to help you select a healthful diet. It’s tempting to ignore them altogether.
If you’ve ever looked at a food label you’ve probably noticed Percent Daily Values (DVs) and Percent U.S. Recommended Dietary Allowances (USRDAs), and possibly wondered what they meant.
Percent Daily Values shows how much of the recommended daily intake of certain nutrients is contained in one serving of a food, based on a 2,000-calorie diet.
For example, a can of Stagg 99 Percent Fat Free Chili lists 10 grams of fiber per serving, or 39 percent of the daily value. That tells you that the chili is a relatively high-fiber food.
Other nutrients for which daily values are listed include total fat, saturated fat, cholesterol, sodium and carbohydrates.
Recommended Dietary Allowances, which provide standards for 12 vitamins, seven minerals and protein, were not originally designed for the public’s use. They were developed in the early 1940s to assist health professionals in planning and evaluating programs and diets for pregnant women, schoolchildren and hospital patients.
The RDAs are generally set at levels higher than the actual nutrient requirements of most people. While the experts generally assume that you can get all the nutrients you need from your food, the annual spending of $2.1 billion on vitamin and mineral supplements indicates that the public thinks otherwise.
The popularity of protein diets and other restrictive eating plans and the increased reliance on fast and overly processed foods, reduces the amount of nutrients people consume. Even though vitamins and minerals are added back to many foods, you may not be covering your nutritional bases without a supplement.
Folic acid is a good example. Especially during pregnancy, a woman needs to get 100 percent of the RDA for folic acid or risk such birth defects as spina bifida. Fortified cereal and dark green vegetables like asparagus and brussels sprouts are excellent sources of folic acid. A vitamin tablet that meets the RDA is a sure way to get the valuable vitamin.
But where’s the cutoff point for vitamins and minerals? If a little is good, is a lot better?
The Estimated Safe and Adequate Daily Dietary Intakes (ESADDI) was developed by the federal Food and Nutrition Board in 1989. Unfortunately, it’s incomplete and currently useless to the public.
The Food and Drug Administration is in the process of face-lifting the RDAs, which were last revised in 1989. The 20 nutrients will be expanded to 26, and each will have four reference points: a deficient level of intake, a minimum requirement, the RDA and a much-needed upper safe level of intake.
Until new guidelines are established, easily understood and accessible, the public will be subject to trendy and incomplete research. For example, you may have read that vitamin A helps with skin and vision health, but a recent study from Sweden claims that excess vitamin A increases the risk of hip fractures by 68 percent.
Beta carotene, a precursor to vitamin A, was thought to lower the risk of lung cancer. But recent studies show that taking 20-30 milligrams (30,000-50,000 International Units) of beta carotene actually raises that risk.
In September 1997, the Nutrition Action Healthletter reported that excess amounts of vitamin E and zinc - 1,600 IU and 50 milligrams, respectively - impaired the immune system.
Calculating your daily nutritional requirements can be difficult. Like any home improvement project, the most simple directions can often turn into complicated tasks. The RDAs will be a work in progress for many years to come.