By Barbara C. Bourassa 

Many Americans have bought soundly into the premise that dietary supplements can help them look younger, feel happier, and stay healthier.  In fact, experts report that more than half of all adults take some type of dietary supplement on a regular basis. But are they really worth all the hype? It depends, say researchers at the National Institutes of Health (NIH) Office of Dietary Supplements (ODS).

Many Americans have bought soundly into the premise that dietary supplements can help them stay young, healthy, smart, energetic, or happy. In fact, experts report that more than half of all adults take some type of dietary supplement on a regular basis. But do we really need them all? It depends, say researchers at the National Institutes of Health (NIH) Office of Dietary Supplements (ODS).

For the last eight years, the ODS has published its Annual Bibliography of Significant Advances in Dietary Supplement Research. This 20-page document highlights 25 of the most significant dietary supplement research advances of the past year—and not all the findings are expected. In the 2006 edition, for instance, one summary details a study reported in the New England Journal of Medicine, conducted as part of the Women’s Health Initiative. “The findings suggest that taking calcium and vitamin D supplements for an average of seven years will not reduce the risk of colorectal cancer,” the researchers write. Another summary, though, suggests that Echinacea can prevent symptoms of the common cold, although researchers note that “appropriately powered clinical studies are required to confirm this finding.”

These examples illustrate the mixed results that many researchers encounter when studying dietary supplements. What’s more, these findings are not meant to be used as broad endorsements. “When we initiated this project in 1999, our objective was to give researchers credit for raising the bar on supplement research and encourage others to follow their lead,” explains Paul M. Coates, PhD, director of ODS, in a written statement. “However, even the highlighted studies should be viewed as clues, not verdicts. Just because a study points to a compound having an interesting effect, it doesn’t mean we are ready to make a broad public health recommendation.”

For many dietary supplements, the jury is still out. But even so, there is still one thing that many nutritionists and researchers agree upon: taking a multivitamin can’t hurt. (The same cannot be said, though, of all dietary supplements.) Most experts agree, though, that food is the best way to get your vitamins. This involves filling your diet with a variety of fruits, vegetables, lean proteins, whole grains, and healthy fats. That said, however, most nutritionists agree that even people who eat very healthfully can’t be sure they’ve covered every vitamin, mineral, or nutrient base—and that’s where a multivitamin can provide extra nutritional needs.

If you decide to take vitamins and supplements, keep these tips from the ODS in mind:

• Does it sound too good to be true? Do the claims for the product seem exaggerated or unrealistic? Learn to distinguish hype from evidence-based science.

• Don’t chase the latest headline. Sound health advice is generally based on a body of research, not a single study. Many news stories about the latest scientific study are often too brief to enable you to make an informed decision.

• Check your assumptions. Don’t assume that all supplements are safe in any dose. When consumed in high enough amounts, for a long enough time, or in combination with certain other substances, all chemicals can be toxic. This includes nutrients, plant components, and other biologically active ingredients.

• Beware of misleading terms. Many weight-loss products claim to be "natural" or "herbal", but this doesn't necessarily make them safe. Their ingredients may interact with drugs or may be dangerous for people with certain medical conditions.

For more information about dietary supplements, including a list of frequently asked questions, visit the ODS website.

Barbara C. Bourassa is a freelance writer and editor based in North Andover, Massachusetts.