There is unfortunately a large emphasis in current vitamin D research that overstates the benefits of vitamin D supplementation on the conclusions of studies conducted on UV exposure from the sun. Such disparities in reporting have obviously increased the supplement market for this valuable nutrient, however vitamin D from sunlight exposure and supplementation may not be interchangeable in terms of effectiveness.
Vitamin D would be essential if it did nothing else. But researchers have discovered that it’s active in many tissues and cells besides bone and controls an enormous number of genes, including some associated with cancers, autoimmune disease, and infection. Hardly a month goes by without news about the risks of vitamin D deficiency or about a potential role for the vitamin in warding off diseases, including breast cancer, multiple sclerosis, and even schizophrenia. In June 2008, a study published in the Archives of Internal Medicine found that low blood levels of vitamin D were associated with a doubled risk of death overall and from cardiovascular causes in women and men (average age 62) referred to a cardiac center for coronary angiography. At a scientific meeting in May 2008, Canadian researchers reported that vitamin D deficiency was linked to poorer outcomes in women with breast cancer. And a large study of aging in the Netherlands published in the May 2008 issue of Archives of General Psychiatry found a relationship between vitamin D deficiency and depression in women and men ages 65 to 95.