Feb. 27, 2007 — We tend to think of vitamins as healthy. But can you have too much of a good thing?
New research suggests this may be the case when it comes to supplements.
In a meta-analysis study published in the Journal of the American Medical Association, researchers reviewed 68 studies involving more than 200,000 patients to determine whether taking high-dose vitamin supplements — in particular, beta carotene, vitamin A, vitamin C, vitamin E and selenium — affected your risk of dying.
Taking large doses of vitamin A increased the risk of death by 16 percent. Smaller increases were seen for vitamin E (4 percent) and beta carotene (7 percent).
Vitamin C and selenium did not appear to affect the risk of dying.
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Information that large doses of some vitamins can be harmful is not new. When taken in excess, the fat-soluble vitamins — vitamins A, D, E and K — are stored in body fat tissues. This can lead to toxic buildup in the liver, brain and heart.
Excess amounts of water-soluble vitamins, on the other hand, are less hazardous because they are eliminated from the body in the urine.
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People "should spend their money on multiple varieties and colors of vegetables and fruits, whole grains, and lean protein," said Dr. John Messmer, associate professor of family and community medicine at Pennsylvania State University's College of Medicine in Hershey, "and stop wasting it on supplements."
Dobsevage agrees. However, she said, "the American diet is so degraded, and so many of us no longer cook whole foods in our own homes for most of our meals, that I often recommend a modest level of vitamin and mineral supplementation — less than RDAs."
