The Forgotten Vitamin
Vitamin D deficiency is a worldwide health problem. Over a billion people worldwide are vitamin D deficient or insufficient. Vitamin D, is described as “the Sun Vitamin”. It is a steroid with hormone like activity. It regulates the functions of over 200 genes and is essential for growth and development. Two major forms of vitamin D. Vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is made naturally by the body when skin is exposed to ultraviolet radiation in sunlight. It is converted to 25-hydroxyvitamin D in the liver. 25-Hydroxyvitamin D then travels through the blood to the kidneys, where it is further modified to 1,25-dihydroxyvitamin D, or calcitrol, the active form of vitamin D in the body. The most accurate method of evaluating a person’s vitamin D status is to measure the level of 25- hydroxyvitamin D in the blood. Usually 50 to 90% of vitamin D is produced by sunshine exposure of skin and the remainder comes from the diet. Natural diet, most people consume, contain little vitamin D. Traditionally the human vitamin D system begins in the skin, not in the mouth. However, important sources of vitamin D are egg yolk, fatty fish, fortified dairy products and beef liver.