Older women can reduce the risk of osteoporosis by taking calcium supplements. So I take a supplement. The problem with all this pill popping, Dr. St. Jeor says, is that people too easily begin to rely on supplements to make up for a less than virtuous diet. But satisfying the recommended daily allowances for every vitamin and mineral doesn't mean you're getting all the nutrients you need in the right balance. Food contains other nutrients that scientists are only now beginning to learn are important.
Supplements also can have a darker side.
Taking too much of one or the other vitamin or mineral can be toxic. There's nothing wrong with taking a sensible multi-vitamin, says Martha Singer, manager of the nutrition unit at Boston University. These sudden romances with the latest miracle vitamin can lead to overdosing, Ms. Singer says. Tomorrow's research often deflates the early promise of today's supplement darling. For example, researchers at the National Cancer Institute concluded earlier this year that supplements of beta carotene, a form of vitamin A, don't prevent lung cancer, and may actually increase cancer risk slightly among smokers.