Vit D in a New Light

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Vitamin D in a New Lightby Donald W. Miller, Jr., MDThere are thirteen vitamins humans need for growth and development and to maintain good health. The human body cannot make these essential bio-molecules. They must be supplied in the diet or by bacteria in the intestine, except for vitamin D. Skin makes vitamin D when exposed to ultraviolet B (UVB) radiation from the sun. A light-skinned person will synthesize 20,000 IU (international units) of vitamin D in 20 minutes sunbathing on a Caribbean beach. Vitamin D is also unique in another way. It is the only vitamin that is a hormone, a type of steroid hormone known as a secosteroid, with three carbon rings. Steroid hormones such as cortisone, estrogen, and testosterone have four carbon rings. Ultraviolet B radiation in sunlight breaks open one of the rings in a steroid alcohol present in the skin, 7-dehydrocholesterol, to form vitamin D (cholecalciferol). The liver changes this molecule into its circulating form, 25-hydroxyvitamin D (calcidiol, 25[OH]D), the "vitamin D" blood tests measure. Cells throughout the body absorb 25-hydroxyvitamin D and change it into 1,25-dihydroxyvitamin D (calcitriol), the active form of vitamin D that attaches directly to receptors on the DNA of genes in the cell’s nucleus. The vitamin D hormone system controls the expression of more than 200 genes and the proteins they produce. In addition to its well-known role in calcium metabolism, vitamin D activates genes that control cell growth and programmed cell death (apoptosis), express mediators that regulate the immune system, and release neurotransmitters (e.g., serotonin) that influence one’s mental state. For whole article: http://www.lewrockwell.com/miller/miller25.html «¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤«¤»¥«¤»§«¤»¥«¤»§«¤»§ - PULSE ON 21st CENTURY ALTERNATIVE MEDICINE! §Subscribe:......... - «¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤«¤»¥«¤»§«¤»¥«¤»§«¤»