The Supplement Frenzy

Which ones work?

WebMD Feature

Aug. 21, 2000 -- For years, I've listened to friends, friends of friends, and even complete strangers talk enthusiastically about the supplements they take. They're not touting just run-of-the-mill multivitamins, but big doses of the so-called antioxidants like vitamins A, C, E, and beta-carotene. They swallow these pills by the handful, hoping to undo the damage from too many cheeseburgers, slow down the aging process, and maybe even prevent disease. And they chide me because I'm not on this shortcut-to-good-health bandwagon.

Antioxidants, they're fond of telling me, neutralize free radicals, those pesky unstable oxygen molecules that -- left to run amok -- can damage cells and perhaps lead to cancer, heart disease, and other ailments. The supplement fans do acknowledge that antioxidants can be found in fruits and vegetables. But, they say, why settle for the relatively small quantities in food when you can get so much more by swallowing a few pills?

I've long been skeptical of these claims, wary of taking a pill to get nutrients already available to me in oranges, broccoli, and the like. But lately I've wondered: Is a nutritious diet really enough, or should I follow my friends' advice and take large doses of supplements? Government experts, interestingly enough, recently cast their vote for food and against pills. But their position has left as many questions as answers, and consumers like me are still confused.

The Science Behind Antioxidants

Here's why people are scratching their heads. According to some studies, the pills seem to have worked wonders. For instance, vitamin E in daily doses of 400 to 800 international units (IUs) reduced the risk of heart attack by 77% in people with atherosclerosis who participated in the Cambridge Heart Antioxidant Study. (Harvard University scientists conducted the research and published their findings in the March 23, 1996 issue of the Lancet.)

But a study that tracked 2,545 women and 6,996 men aged 55 and older found that those who took vitamin E for five years suffered just as many strokes and heart attacks as those taking a placebo. (See the Jan. 20, 2000 issue of the New England Journal of Medicine.) Some research has even suggested that antioxidants may increase the risk for certain ailments. For instance, in a study published in the April 14, 1994 issue of the New England Journal of Medicine, researchers looked at more than 29,000 male smokers to see if vitamin E and beta-carotene could prevent disease. They found that large doses of beta-carotene appeared to raise the risk of lung cancer, while the vitamin E had no effect.

This spring a panel of top scientists, convened by the federal Institute of Medicine, weighed in. They concluded that we should be getting our antioxidants from the foods we eat, not popping handfuls of pills.

"There is not sufficient evidence that taking antioxidants in large doses will prevent chronic diseases such as heart disease," says Norman I. Krinsky, PhD, a Tufts University biochemist who chaired the panel. Still, the verdict could change, he says, if a raft of yet-to-be-completed studies turns up enough evidence to prove that supplements are worthwhile.

For now, then, here are the doses recommended by the panel:

  • Vitamin C, 75 milligrams a day for women, 90 for men, with an upper limit of 2,000 milligrams.
  • Vitamin E, 15 milligrams, with a max of 1,000 milligrams a day.
  • Selenium, 55 micrograms, with an upper limit of 400 micrograms a day.
  • No daily recommendation was given for beta-carotene.

Caution Warranted

The experts on the federal panel are not the only ones preaching caution about consuming large quantities of supplements. Mark S. Meskin, PhD, RD, an associate professor of food, nutrition, and consumer sciences at California State Polytechnic University in Pomona, Calif., is one of many nutrition experts who say the panel's recommendations reflect an honest appraisal of currently available research. He, too, advises consumers to skip the pills and focus on their diets. "My advice is to do what most Americans don't do -- eat fruits and vegetables," Meskin says. "Most don't meet the five-a-day [recommendation of the U.S. Department of Agriculture]."

Numerous studies, he says, find that eating more fruits and vegetables reduces disease risk. In fact, it's not that difficult to get the recommended intake of antioxidants from food. For example, an orange contains 75 milligrams of vitamin C, the daily amount recommended for women. Two oranges give men plenty more than the 90 milligrams recommended for them daily. Three-quarters of a cup of almonds provides 21 milligrams of vitamin E, 6 over the 15 milligrams recommended for both men and women.

Supplement enthusiasts would argue that the current daily recommendations may not be protective, but Meskin offers more food for thought. By eating antioxidant-rich foods, you take in still more disease-fighting substances: additional vitamins, for instance, and dietary fiber -- and perhaps others that haven't even been identified yet. All the more reason, he says, to pay attention to diet -- and sit tight for additional studies to prove or disprove the worth of antioxidant supplements.

Focus on Food

So, I've read the panel report, I've scanned the studies, and I'd like to live to 100 just like everyone else. My decision? To err on the side of caution, at least temporarily. Instead of joining the ranks of pill poppers, I'm vowing to pay closer attention to my daily intake of fruits and vegetables, which is often measly despite my best intentions.

But I eagerly await the next batch of antioxidant studies, which might just change some minds -- including my own.

Kathleen Doheny is a Los Angeles journalist and a contributing editor for WebMD. She also writes for The Los Angeles Times, Shape, Modern Maturity, and Working Woman.

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According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

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