Bone Health, Depression, Seasonal Affective Disorder, Osteoporosis,
Osteopenia, Cardiovascular Health, Autoimmune Disease, Disease Prevention
Vitamin D is a fat-soluble vitamin that exerts its effects by binding to receptors in the body is known as Vitamin D Receptors (VDR's). Essentially, every tissue and cell in the body has a VDR, including the brain, heart, stomach, pancreas, skin, and immune cells. Because of Vitamin D'S diverse actions throughout the body, deficiency has been associated with numerous conditions including osteoporosis, depression, cardiovascular disease, neurodegenerative disease, type 1 diabetes, rheumatoid arthritis, multiple sclerosis, and psoriasis. A recent study published in the Archives of Internal Medicine suggests that low levels of Vitamin D may increase the risk of death from all causes by 26 percent. One of Vitamin D'S most well-known functions is promoting calcium absorption in the gut and maintaining the proper calcium and phosphate concentrations needed for bone mineralization. Defective bone mineralization can cause the bones to soften, a condition known as rickets in children and osteomalacia in adults. Vitamin D is required for bone growth and bone healing after fractures and breaks. Without adequate Vitamin D, bones can become thin, brittle, and misshaped. Along with Calcium, Vitamin D helps protect against Osteoporosis. Often referred to as "the sunshine vitamin", Vitamin D can help alleviate depression in sunlight-deprived individuals. A lack of adequate sunlight often leads to mood
disorders such as seasonal affective disorder (SAD), which has been estimated to affect over 11 million Americans. This disorder occurs during the winter months when sun exposure is low and Vitamin D levels in the body drop. A study published in the Nutrition Journal regarding the correlation between depression and Vitamin D deficiency revealed that patients receiving a higher dosage of Vitamin D (4,000 I.U.) experienced greater mood-enhancing benefits than the patients who received the lower dosage (600 1.U.). More and more studies are being conducted demonstrating the role of Vitamin D in Cancer prevention. Vitamin D is one of the most potent inhibitors of cancer cell growth. Many genes encoding proteins that regulate cell proliferation, differentiation, and apoptosis is modulated in part by Vitamin D. Deficiency of the vitamin has been linked to colon, breast, prostate, ovarian and esophageal cancer. Dr. Cedric Garland, an adjunct professor at the Department of Family and Preventative Medicine at U.C. San Diego, explains "Vitamin D metabolites inhibit cell growth by upregulating the syntheses of compounds that cause epithelial cells to strongly adhere to their neighboring cells. This causes contact inhibition, preventing excessive cell division. As a result, the process leading to cancer does not begin. If cancer does begin, Vitamin D metabolites prevent tumor angiogenesis, depriving the tumor mass of oxygen and glucose." Vitamin D also offers protection against autoimmune disorders. Low vitamin D status has been implicated in autoimmune disorders such as multiple sclerosis, rheumatoid arthritis, type 1 diabetes, psoriasis, and inflammatory bowel disease. Vitamin D seems to decrease the autoimmune response as well as the severity of symptoms. Studies show that Vitamin has direct and indirect regulation of T cell development and function. In the absence of Vitamin D, autoreactive T cells develop; in the presence of Vitamin D the balance in the T cell response is restored and autoimmunity avoided. Vitamin D deficiency is also associated with an increased risk of cardiovascular disease, especially high blood pressure. In one particular study, researchers found a 62% higher risk of cardiovascular disease in participants with low levels of Vitamin D. It is speculated that Vitamin D'S role in cardiovascular health is due to the fact that Vitamin D receptors are located in vascular smooth muscle and the inner lining of the body's vessels. Other roles Vitamin D has in human health include modulation of neuromuscular and immune function and reduction of inflammation. Vitamin D deficiency has been associated with muscle weakness and pain in both adults and children. Research shows Vitamin D supplementation can provide relief for fibromyalgia sufferers and those with chronic back pain. In supplements, Vitamin D is available in two forms, D2 (ergocalciferol) and D3 (cholecalciferol). Evidence shows that Vitamin D3 is more than three times as effective as Vitamin D2 in raising blood serum concentrations of Vitamin D and maintaining sufficient levels for a longer time. Vitamin D3 is also more effective than D2 for cancer prevention. Getting adequate Vitamin D from natural food sources and sun exposure can be difficult. Those most likely to suffer from Vitamin D deficiency are individuals who live in northern climates, those who avoid the sun or wear sunscreen, and breastfed infants (human milk alone contains very little Vitamin D). The American Academy of Pediatrics (AAP) recommends that exclusively and partially breastfed infants be supplemented with 400 IU of Vitamin D per day. Adults over the age of 50 are also at an increased risk of developing Vitamin D insufficiency due to the fact that as people age, skin cannot synthesize Vitamin D as efficiently from sunlight. The kidneys are also less able to convert Vitamin D to its active form. Studies show Vitamin D deficiency in older adults is associated with low mood and impaired cognitive performance. Others that are likely to be Vitamin D deficient include those with limited sun exposure, those with dark skin, those with fat malabsorption (Vitamin D requires some dietary fat in the gut for absorption), and those who are obese (Vitamin D is not able to efficiently release into the circulation).