Extended role of Vitamin D

Vitamin D is gaining status in the medical and popular media. Its role in the development and maintenance of bones is well established, but there is growing research suggesting it can also reduce the risk of cardiovascular disease, cancer, and autoimmune and infectious diseases.
Vitamin D is synthesized from a cholesterol derivative in skin exposed to sunlight (major source) or it can be obtained from the diet (few sources)or supplements. Sunlight destroys any excess previtamin D in the skin, therefore, toxicity as a result of vit D does not occur.
Deficiency in vitamin D is becoming recognized as a global pandemic. Risk factors for deficiency include living in northern latitudes (such as Canada), dark colouration skin, regular use of suncscreen, aging (persons more than 70 years of age have a 75% reducation in ability to produce vitamin D in skin), obesity and interaction with drugs (e.g., phenytoin, phenobarbital, carbamazepine, corticosteroids). Deficiency may lead to rickets, falls and decreased bone mineral density. Most trials examined in the review reported a small increase in bone mineral density when vitamin D was taken in doses > 700IU/day with calcium. Reduction in fall risk was most evident in postmenopausal women and elderly men.
If vitamin supplementation is indicated, caution is warranted because too much vitamin D might be harmful. Most experts now recommend that children and adults of all ages who do not receive adequate sun exposure should receive a minimum of 1000 IU vitamin D daily in order to maintain a healthy vitamin D level. Sun is the major source of Vitamin D it gives 400 IU vitamin D when exposed 10-15 minutes bare arms and face. Sources of vitamin D from diet includes, egfg yol, milk, fortified orange juice, salmon and tuna. As supplements, vitamin D is available in two sources, Vitamin D3 (cholecalciferol)and vitamin D2 (ergocalciferol). D3 is more potent than D2. D2 may be preferred by vegans as it is not derived from an animal source.