Vitamin D is essential for calcium absorption and bone health. Studies have linked vitamin D deficiency not only to bone diseases but also to autoimmune disorders and anticancer effects in melanoma, ...

Though vitamins won't expire and become unsafe, they will lose potency, which means they're not doing you any good.

Dear L.M.: Overdosing on vitamin D is dangerous. Last month, I had a patient who had elevated levels of calcium, which caused typical symptoms of confusion, vomiting and muscle weakness. She was found ...