Scientists are studying vitamin D to see how it affects health. Here are a few examples of what this research has shown.
As they get older, men and women can develop weak and fragile bones, a condition called osteoporosis. Supplements of both vitamin D and calcium can reduce the risk of bone loss and fractures in elderly people. Talk with your healthcare provider about vitamin D and calcium as part of a plan to prevent or treat osteoporosis as you age.
Some studies have tried to find out whether getting more vitamin D can affect the chances of developing cancers of the colon, breast, prostate, pancreas, and other parts of the body. It's too early to say whether low levels of vitamin D affect one's risk of cancer.
Can vitamin D be harmful?
In healthy children and adults, vitamin D at doses up to 2,000 IU is safe. (In infants, up to 1,000 IU is safe.) When taken as a supplement at very high doses, vitamin D can cause nausea and vomiting, confusion, and serious heart problems. Vitamin D made in the body from sunlight does not rise to dangerous levels.
Does vitamin D interact with any medicines or dietary supplements?
Yes. For example, prednisone and some medicines taken to lose weight, lower cholesterol, or control epileptic seizures can raise the need for vitamin D.