By the way, doctor: Am I taking too much vitamin D?

Q. I take Fosamax with vitamin D and a multivitamin that contains vitamin D. Now I see my calcium tablets also have vitamin D in them. Am I in danger of getting too much of this vitamin?

A. This is a complicated issue, because there's some disagreement over the optimal daily intake for this vitamin. There's no question that vitamin D is essential for healthy bones. It promotes the absorption of calcium and phosphorus from the intestines — a fundamental step in bone growth and repair. Adequate vitamin D is especially important for women who have osteoporosis or are at risk for it. Studies also suggest that vitamin D bolsters the immune system and in sufficient doses helps prevent certain forms of cancer. In September, researchers reported finding a link between vitamin D supplementation and reduced mortality (see "Lower death rate in vitamin-D takers").

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