Vitamin D

Vitamin D is a fat-soluble vitamin that plays a role in many important body functions. It is best known for working with calcium in your body to help build and maintain strong bones. Vitamin D is also involved in regulating the immune system and cells, where it may help prevent cancer.

Your body stores vitamin D and makes vitamin D when your skin is exposed to sunlight. Vitamin D is also found in some foods, mostly ones like milk that have been fortified with vitamin D. There are two forms of vitamin D: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Some research suggests that cholecalciferol is better at raising levels of vitamin D in the blood.

In children, a vitamin D deficiency can cause rickets, a disease that results in soft, weak bones. In adults, many people may not be getting enough vitamin D, especially those who live in northern areas (like the northern half of the U.S.) and the elderly. People with dark skin do not absorb sunlight as easily as those with light skin, so their risk of low vitamin D is even higher. One study suggests that three quarters of adults in the U.S. have low levels of vitamin D.

That's important because researchers are beginning to find that low levels of vitamin D may be linked to other diseases, including breast and colon cancer, prostate cancer, high blood pressure, depression, and obesity. The evidence doesn't prove that too little vitamin D causes these conditions, but that people with higher levels of vitamin D are less likely to get these diseases.

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Review Date: 2/4/2016  

Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.

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