Vitamin D is one of the most important nutrients in the human diet. It is essential for almost all cell processes, helps bones absorb calcium and keeps certain diseases at bay. Researchers have known for some time that vitamin D supplementation may reduce the risk of cancer, but recent inquiry has found that more is needed than once thought.

A study published in the journal Anticancer Research determined that the risk of cancer and other diseases drops by half only when patients are prescribed between five and 10 times the maximum dose recommended from meals.

The research was spurred by a National Academy of Sciences Institute of Medicine report, which found that 4,000 International Units (IUs) of the vitamin is safe for daily consumption. By contrast, the National Institutes of Health recommends taking 600 to 800 IUs each day.

Few foods naturally contain vitamin D. These include mushrooms, eggs and cod liver oil. In their absence, taking a daily multivitamin may promote good health and well-being.