Health Articles : Vitamins and Supplements : Vitamin D
Vitamin D : Vitamin D Synthesis
25 Hydroxy Vitamin D25 hydroxy Vitamin D is commonly known as Vitamin D. It is a fat soluble vitamin that is found in food. ..... Vitamin D is also called as Cholecalciferol. It is a steroid hormone that regulates levels of Calcium and Phosphorous in the body. The term Vitamin d refers to a group of steroid molecules. Vitamin D is not a true vitamin, as people receiving adequate exposure to sunlight do not require dietary supplement of this Vitamin.
Cholecalciferol is generated in the body when the precursor molecule 7-dihydrocholestrol absorbs light energy. Vitamin D is synthesized within the body in the hormonally active form. This metabolism occurs in two steps. In the liver, cholecalciferol is hydroxylated to 25 hydroxychalciferol by the enzyme 25-hydroxylase. The second step occurs in the kidney , where 25 Vitamin D serves as substrate for 1- alpha-hydroxylase giving 1,25 dihydroxycholecalciferol . This is the biologically active form of Vitamin D. Vitamin D and its forms are hydrophobic and are transported in the blood by carrier proteins .The major carrier is called the Vitamin D binding protein.
The hepatic synthesis of 25-hydroxycalciferol is not strictly regulated. The levels of this molecule in the blood affects the quantity of Vitamin D synthesized. On the other hand, the synthesis of 1alpha-hydroxylase is efficiently regulated. In fact, it serves as the control point in the production of the active hormone. The parathyroid hormone is the main inducer of 1-alpha-hydroxylase.
The skin production of Vitamin D goes down with age. In the aged, decreased Vitamin D synthesis is aggravated by lifestyle changes leading to a reduced exposure to the sun. Studies show that 54% of homebound old people and 38 % of nursing home patients were Vitamin D deficient. Vitamin D synthesis also depends on the radiation absorbed. This varies with different skin pigmentation, latitude, atmospheric conditions, season, time of day and duration of exposure. An interesting study shows that cutaneous production of this vitamin does not occur from November to February in Boston, Massachusetts, Edmonto and Canada. Vitamin D synthesis is known to decrease considerably or completely cease by the application of sunscreen. Dark skin pigmentation makes some people more prone to vitamin D deficiency in the northern latitudes.
Vitamin D ProstateVitamin d is an important organic nutrient very much essential for the body .it is a fat soluble vitamin and is ..... Typical natural diets do not contain sufficient quantities of Vitamin D. Thus, adequate exposure to the sun and dietary supplements are vital to preventing deficiencies. Recently, Vitamin D has been proved to be present in a variety of cells. It has various biological functions other than control of mineral metabolism.
MS And Vitamin DMS basically is the abbreviation of the medical term of multiple sclerosis. The cause of multiple sclerosis involves immune attacks against the .....
Natural Vitamin DVitamin D is classified as a fat soluble vitamin. It is naturally available in different types of fruits, vegetables and other plant parts. It .....
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