Vitamin D is an oil-soluble vitamin that has several important functions in the body:

• It helps to absorb dietary calcium and phosphorus from the intestines.
• It suppresses the release of parathyroid hormone, a hormone that causes bone resorption.

Through these actions, vitamin D keeps the calcium and phosphate levels in the blood normal, thereby promoting bone health. Vitamin D may have other benefits, such as improving muscle and immune function, but these areas require more research.