Good Vitamin for the Bones
For years, the media have trumpeted the vital role calcium plays in preventing osteoporosis — a bone-thinning disease that afflicts 10 million Americans. Almost 34 million more are estimated to have low bone mass, placing them at increased risk for osteoporosis. The calcium clamor is so loud it sometimes drowns out messages about another nutritional necessity, vitamin D. Without enough vitamin D, the body cannot absorb calcium and deposit it in the bones.
The human body makes its own vitamin D when ultraviolet-B (UV-B) radiation from the sun interacts with a chemical in the skin. About five to 15 minutes of unfiltered sun exposure a day is usually enough. But the sunshine method isn’t 100 percent reliable for everyone, particularly for older individuals, who are at the highest risk for weakened bones and fractures. Reasons for this include:
· The skin’s ability to make vitamin D from UV-B becomes less efficient as we age.
· Darker skin blocks out up to 95 percent of UV-B rays.
· Sunscreens absorb UV-B before the skin can form vitamin D.
· The earth’s ozone layer screens out UV-B in northern latitudes during the winter.
· It is not always possible to get outdoors on sunny days.