Vitamin D has several chemical forms in the body. It regulates levels of calcium and phosphorus in the blood, has a role in normal bone mineralization, keeps the nerves and muscles healthy and modulates the immune system. Vitamin D deficiency is associated with numerous health problems, including rickets and osteomalacia, which are diseases of bone mineralization. Deficiency is associated with several conditions. Issues of vitamin deficiency should be referred to a health-care professional.
Dietary Problems
Certain foods contain vitamin D. An absence or low intake of these foods leads to low vitamin D levels. According to a 2007 review article in the New England Journal of Medicine by Dr. Michael F. Holick, diets high in oily fish prevent vitamin D deficiency. Shiitake mushrooms, cod liver oil and egg yolk all have vitamin D. Certain foods may be fortified with vitamin D as well. Milk and other dairy products such as cheese and yogurt often have vitamin D added. Prescription and over the counter supplements are also available.
Inadequate Sun Exposure
Sun exposure has been linked to premature aging, skin damage and skin cancer. But inadequate sun exposure may be a source of vitamin D deficiency in some people. According a review article in the New England Journal of Medicine, ultraviolet B radiation penetrates the skin and converts a chemical called 7-dehydrocholesterol to previtamin D3, which is quickly converted to vitamin D3. People living at higher latitudes have higher rates of cancer, which may be related to vitamin D deficiency.
Diseases
According to "Robbins and Cotran Pathologic Basis of Disease" by Dr. Vinay Kumar, vitamin D from the diet and the skin is converted by the liver and then the kidneys to its most active form. Different organ diseases can result in vitamin D deficiency. Intestinal problems that result in poor absorption are a source of deficiency. Kidney and liver diseases also can result in deficiency. Since vitamin D is fat-soluble, obesity can decrease available blood levels by sequestering vitamin D in fat stores.
References
- "New England Journal of Medicine"; Vitamin D Deficiency; Michael F. Holick, M.D., Ph.D.; 2007
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, M.D.; 8th Ed.; 2009
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