Evaluating vitamin and mineral supplement claims
Be careful when considering buying a vitamin and mineral supplement.
- Don't be swayed by nonnutritional promotion. For example, a company may claim that you are not getting enough nutrients because you are eating too many processed foods. The answer is eating a more balanced diet, not using supplements.
- Companies that manufacture or market dietary supplements are not required to prove safety or effectiveness as food producers are. In fact, supplements must be proved harmful before they can be banned by the U.S. Food and Drug Administration.
- Personal stories are often used to illustrate how vitamin and mineral supplements can help you. One person's success with a supplement does not mean that it will help you.
- Quick and dramatic results are often promised. If it sounds too good to be true, it probably is.
- Vitamins from natural sources are sometimes claimed to be better than vitamins from synthetic (man-made) sources. However, most synthetic vitamins (except vitamin E) are as good as natural vitamins. Natural vitamin E is absorbed better by the body than synthetic vitamin E. In the case of folic acid, synthetic folic acid is absorbed better than natural folate found in food.
- A "natural" claim is sometimes made when only a small amount of the nutrient is from a natural source. Vitamin and mineral supplements claiming high potency generally are synthetic.
Although there is little evidence of harm from low doses of vitamin and mineral supplements, taking doses that are higher than the dietary reference intakes (DRIs)/recommended dietary allowances (RDAs) for some nutrients may be harmful.
- High doses of vitamins A, B6, D, K, and niacin, and the minerals selenium and iron can be toxic. Upper-level consumption limits also have been set for other vitamins and minerals.
- Too much of one vitamin or mineral can make others less effective. For example, high doses of vitamin E can interfere with vitamin K, and high levels of zinc may decrease the absorption of iron and copper.
Remember that you can usually get all necessary nutrients from food, and with the recent discovery of so many healthy substances, such as phytochemicals, in our foods that have not yet been duplicated in supplements, eating a variety of healthy foods appears to be a better choice than using supplements.
If you are thinking of using nutritional supplements, ask your health professional whether he or she feels they are necessary for you.
| Author: | Caroline Rea, RN, BS, MS | Last Updated: February 23, 2007 |
| Medical Review: | Ruth Schneider, MPH, RD - Diet and Nutrition Rhonda O'Brien, MS, RD, CDE - Diabetes Educator | |
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