& Joannie Dobbs Wednesday,
July 8, 1998
Vitamin pill no substitute for good
“Eat Right and Take a Multivitamin” was the title of an editorial published recently in the prestigious New England Journal of Medicine (April 9). This editorial represents a major departure from the traditional view that supplements are unnecessary if you eat a reasonable diet. The author, Dr. Godfrey P. Oakley Jr. from the Centers for Disease Control and Prevention points out that since the mid 1970s, 25 percent of American adults have consumed multivitamin supplements regularly and that current research indicates that these people and their children are healthier.
If people eat a diet with a wide variety of wholesome foods in the right proportions, they can get plenty of essential nutrients. However, the average American diet has become limited in the variety of foods that are regularly consumed. And today's convenience foods rarely contain the fruits and vegetables that we need to stay healthy.
In an effort to prevent nutrient deficiencies in the population, white flour is now enriched with iron, vitamins B-1, B-2, niacin, and most recently, folic acid. But these efforts do not help those who consume other starches such as rice for their staple food or wheat flour products that are not made with enriched flour, such as most pastas. Enriched flour does not contain important antioxidants such as vitamins C and E.
So, should you be taking a supplement or should you be eating better? Dr. Oakley would probably answer, “Both!” There is no substitute for eating a wide variety of wholesome foods, because of numerous beneficial food components still being identified.
Here are considerations to take into account. Is more always better? No. Some of the supplements on the market contain nutrient concentrations so high that they function more like drugs than vitamin supplements, including the potential for adverse side effects. Above a certain level of intake, any vitamin or mineral can cause problems. How much is too much? This varies from one nutrient to another and probably even from one person to another.
Toxic effects of excessive nutrient intake are rarely noticeable in the short term. For example, vitamin D at only 5 to 10 times the Recommended Dietary Allowance can cause serious problems such as calcification of the kidneys. Symptoms may not occur until after many months or years of excessive intake. And by the time someone sees a physician about the problem, the vitamin supplementation may have been changed or stopped, making it difficult to determine the cause.
“Tolerable Upper Intake Levels” have been set for some nutrients by the Food and Nutrition Board of the Institute of Medicine . These recommendations are for total daily intake from food, fortified foods such as breakfast cereals, nutritional drinks, sports bars and actual pill supplements. Consequently, supplements should contain significantly lower levels than listed below. Some “Tolerable Upper Intake Levels” for daily intake by adults include,
Calcium – 2500 milligrams
Phosphorus – 4000 milligrams
Vitamin D – 50 micrograms/2000 Ius
Niacin – 35 milligrams
Vitamin B-6 – 100 milligrams
Folic acid – 1000 milligrams
Work is being done to set other upper limits. Until then, we know that toxic symptoms have been reported in healthy adults taking 15,00 IUs/day of vitamin A and 900 micrograms/day of selenium over extended periods of time.
For healthy individuals, balance should be the guideline, about 3 times the RDA, from all sources. Children, pregnant woman, and those with special medical needs should follow the advice of their physicians.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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