Stampfer also takes a supplement of vitamin D, the so-called "sunshine vitamin" and the subject of the latest debate among researchers. Vitamin D, which is made when the skin is exposed to sunlight, has long been seen as essential in building strong bones. Recent findings suggest it could also play a role in reducing heart disease, preeclampsia in pregnant women and a variety of cancers.
In addition, pediatric researchers think vitamin D deficiency may be more common than they realize, especially in breast-fed infants, since breast milk contains low levels of the nutrient. The American Academy of Pediatrics is considering increasing its recommended vitamin D supplementation in infants from 200 IU to 400 IU after a recent resurfacing of rickets, a softening of the bones that takes place when children do not get enough vitamin D and a condition that was thought to be wiped out with the fortification of milk.
But Picciano points out there is no evidence that supplemental vitamin D is beneficial for adults. "We need many more rigorous studies before decisions can be drawn," she said. "The horizon looks promising, but we may get there and see a storm. We don't know what we may find."
Stampfer disagrees and says such studies can take decades. For now, he thinks, the evidence is clear that a vitamin D supplement is beneficial, especially to those like him who live in northern climates with limited sun exposure in the winter. He takes a daily multivitamin with 1,000 IUs of vitamin E as well as a vitamin E supplement.
"I figure the risk is about zero, the cost is very low, and the potential for benefit is substantial," he said. "You could either wait for the perfect data, or you make the best judgment you can, recognizing it's imperfect."
Of course, it's possible to get too much of a good thing. Excessive intake of such vitamins as beta-carotene and calcium have been found to be harmful. Trials have shown too much beta carotene, once thought to help lung health, can be toxic, while excessive calcium can lead to elevated levels in the blood and cause kidney problems.
And even helpful vitamins are not a substitute for healthy living, Stampfer said. "I think it's a small part of a healthy lifestyle."
With so many products on the market, Jennifer Brewington is not sure if vitamins do any good. Brewington, 55, keeps the books for her husband Rob's software consulting business in Howard County. He is convinced that a multivitamin has helped keep him relatively healthy since he started taking one eight years ago, when robust business meant working grueling hours, skipping meals and getting little sleep.
