TUESDAY, Jan. 10 (HealthDay News) -- Studies have shown that vitamin D is critical for bone health and could have a protective benefit for the heart, but new research suggests that too much of it could actually be harmful. "Clearly, vitamin D is important for your heart health, especially if you have low blood levels of vitamin D. It reduces cardiovascular inflammation and atherosclerosis, and may reduce mortality, but it appears that at some point it can be too much of a good thing," study leader Dr. Muhammad Amer, an assistant professor in the division of general internal medicine at...