Vitamin D is good for your bones, doctors have said for years, but new research suggests that taking a vitamin pill a day might extend your life.
The findings, published yesterday in the journal Archives of Internal Medicine, add to the growing medical literature about the benefits of what is sometimes called the "sunshine vitamin" because it is produced by the skin in response to sunlight. Recent studies have linked vitamin D deficiencies to higher risk of cancer, diabetes and multiple sclerosis. It could play a role in reducing heart disease and preventing pre-eclampsia in pregnant women.
"It's very new to see [the effects of] vitamin D on organs different than the bones," said Dr. Philippe Autier, a co-author of the study. "These are very ordinary doses. You don't need four or five pills a day. ...
"You should probably get rid of all the other" vitamins in the medicine cabinet, Autier said by phone from Lyon, France, where he is a researcher at the International Agency for Research on Cancer. "At this point, that's where we are. This is quite real."
Consumers are getting used to being told about new benefits of vitamins.
Yesterday, a team led by Johns Hopkins scientists reported that vitamin C inhibits the growth of some tumors in mice. In recent years, vitamin E, beta-carotene and other antioxidants were praised as having miracle properties but when more research was done, they lost some of their luster. One trial last year showed that patients with neck cancer who received large doses of vitamins C, E and beta carotene experienced fewer side effects of cancer treatments, but in the end they died at twice the rate of those who didn't get vitamins.
Past experience means there "is some need to be cautious" about vitamins, said Edgar Miller, associate professor of medicine at Johns Hopkins and an antioxidant researcher:
"I think there is enough evidence to recommend vitamin D supplements in most women, certainly who are older and have dietary deficiencies. How high a dose? We don't know. Is there a threshold of benefit beyond which there's harm? That's something that needs to be studied."
Still, he said, "everything seems to be lining up very well with vitamin D."
Autier's analysis looked at 18 trials involving vitamin D supplements that included more than 57,000 patients and evaluated doses ranging from 300 international units to 2,000 international units. Most commercially available supplements contain 400 to 600 IU. Over an average of nearly six years, those who took vitamin D had a 7 percent lower risk of death from all causes than those who did not.
