You've probably known for years that you need vitamin D for healthy bones. But some surprising new research suggests that vitamin D may actually help you live longer.

Recently, researchers based in Lyon, France, and Milan, Italy, reviewed 18 studies that followed more than 57,000 older adults in the United States, Britain and Europe over about five and a half years. They found that, overall, people taking vitamin D supplements were 7 percent less likely to die during the studies than those on a placebo.

Experts aren't sure why vitamin D seemed to help these people live longer. But vitamin D's benefits seem undeniable: Other studies have found that it helps build strong muscles; may prevent many kinds of cancer, including that of the breast, prostate and colon; and may even help boost your immune system.

"It's a new concept," says Michael Holick, Ph.D., M.D., a professor of medicine at Boston University Medical Center and author of The UV Advantage. "We now know that every tissue in the body has a receptor for vitamin D and requires vitamin D for maximum health."

And here's one more thing you may not know: You're probably not getting enough of it.

According to a recent article written by Holick and published in the New England Journal of Medicine, some studies suggest that between 40 and 100 percent of older Americans and Europeans are low in vitamin D. More than half of postmenopausal women taking medicine for osteoporosis are D-deficient. And half of all African-American children and adults in the United States need more of the nutrient, Holick says.

Here's an easy solution: Take a supplement (available at drug stores) of 1,000 International Units (IUs) of vitamin D every day. That's more than the current Recommended Daily Allowance for older adults, but many doctors now say the RDA should be increased.

Researcher Neil Binkley, M.D., Associate Professor of Geriatrics and Endocrinology in the Department of Medicine at the University of Wisconsin in Madison, agrees. He's cautious of touting vitamin D as a cure-all:

"It's not the fountain of youth," he says. But like Holick, he thinks everyone should take 1,000 IUs a day. "It's what I gave my mother for Christmas," he says.

Go to ELDR.com/resources [1] for links to more info on vitamin D.