The Important Vitamin You're Probably Lacking

On the seemingly ever-changing list of what vitamins and minerals we ought to be taking—and in what amounts—vitamin D has long been a solid, boring standard. For years, we were told that we'd have our needs covered if we drank fortified milk, got a few minutes of daily sun exposure (which delivers the vitamin directly to us through our skin), or took calcium or multivitamin supplements containing additional amounts of vitamin D.

That accepted wisdom is no longer. Recent research shows that many people living in the United States and around the world are getting insufficient levels of vitamin D, putting them at risk for health problems. If you spend a lot of time indoors at work or home, have dark skin, are older or severely overweight or have certain medical conditions, you're more likely to be vitamin D deficient. Even if you spend a lot of time outdoors but wisely cover up with sunscreen or sunblock, you also keep the vitamin D in sunlight from reaching your skin and being stored by your body.