How much vitamin D should I take per day?

Q: What is the recommended vitamin D intake per day? Is it true that it can prevent cancer?  -Oscar

A: The recommended intake for vitamin D has increased to a minimum of 1,000 IU daily. A blood test can measure your vitamin D levels. Your physician may recommend a much higher dose, particularly if you’re at risk of a disease known to be associated with vitamin D. Cancer is one such disease – particularly that of the colon, prostate, and breast. While it is not yet known whether vitamin D can prevent cancer, deficiency in the vitamin appears to be a strong risk factor.