Vitamin D serves an important role in the absorption of calcium and phosphate for proper bone health but also plays a protective role against a variety of diseases. Vitamin D comes from foods such as milk, cheese and certain fish but is also synthesized in the skin from sunlight. Rickets and osteomalacia are two classic diseases related to vitamin D deficiency, but a lack of vitamin D can also play a role in several other disease processes.
Rickets
Severe and extended vitamin D deficiency in children can lead to a condition known as rickets in which the bones become soft and weak. Low levels of vitamin D cause the bones to release calcium and phosphate into the blood leading to poor bone metabolism and health. Symptoms of rickets include bone pain and tenderness, deformities of the teeth and skeletal system and growth impairment. Rickets is rare in the United States because many foods are fortified with vitamin D, but it is still a concern in developing countries, according to the World Health Organization.
Osteomalacia
Osteomalacia is a bone disease caused by a lack of vitamin D that is essentially the same as rickets but occurs in adults. Deficient amount of vitamin D in adults may be due to insufficient dietary vitamin D, celiac disease, kidney or liver disorders, certain medications or surgeries or insufficient exposure to sunlight. Ultraviolet sunlight converts a form of cholesterol in the skin into vitamin D for the body, and the majority of individuals depend on this to fulfill vitamin D requirements, according to an article in the December 2004 issue of the American Journal of Clinical Nutrition. There may be no symptoms in the early stages of osteomalacia, but it can eventually lead to bone pain in the lower spine, pelvis or legs and muscle weakness and decreased muscle tone.
Other Diseases
Vitamin D deficiency has also been linked to schizophrenia and depression and is associated with an increased risk of certain cancers, according to a review article by Dr. Michael Holick in the July 2007 issue of the New England Journal of Medicine. He stated that epidemiological studies have shown an association between vitamin D deficiency and a 30 to 50 percent increase in colon, prostate and breast cancer.
References
- World Health Organization: New Clues on Rickets
- Medline Plus: Rickets
- American Journal of Clinical Nutrition: Sunlight and Vitamin D for Bone Health and Prevention of Autoimmune Diseases, Cancers, and Cardiovascular Disease
- Medline Plus: Osteomalacia
- New England Journal of Medicine: Vitamin D Deficiency
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