The Wonder Vitamin You’re Not Getting Enough Of

You drink fortified milk. You walk outside for 30 minutes a day. And you take a multivitamin. So you've got vitamin D covered, right?

Not if you're like 40 to 85 percent of North Americans. And if you're over 60, have dark skin, or slather on sunscreen every time you step outside, put yourself in the 85 percent zone. That's bad news for your health. Not just because you need D to build strong bones, but because a steady stream of recent research suggests this familiar nutrient is responsible for more good deeds than a string of superheroes put together—including the biggie that it can even help you live longer. >>>