Vitamin D supplements are given to treat or to prevent osteomalacia and rickets. Its discovery was due to effort to find the dietary substance lacking in children with rickets (the childhood form of osteomalacia). Vitamin D has a significant role in calcium homeostasis and metabolism. Calcitriol also has other effects, including some on cell growth, neuromuscular and immune functions, and reduction of inflammation. Calcitriol circulates as a hormone in the blood, having a major role regulating the concentration of calcium and phosphate, and promoting the healthy growth and remodeling of bone.
Calcifediol is further hydroxylated by the kidneys and some of the immune system cells to form calcitriol (1,25-dihydroxycholecalciferol), the biologically active form of vitamin D. These two vitamin D metabolites (called 25-hydroxyvitamin D or 25(OH)D) are measured in serum to determine a person's vitamin D status. Ĭholecalciferol is converted in the liver to calcifediol (25-hydroxycholecalciferol) ergocalciferol is converted to 25-hydroxyergocalciferol. Instead it can be considered a hormone, with activation of the vitamin D pro-hormone resulting in the active form, calcitriol, which then produces effects via a nuclear receptor in multiple locations. Because vitamin D can be synthesized in adequate amounts by most mammals if they get enough sunlight, it is not essential and therefore is technically not a vitamin. It is activated by two protein enzyme hydroxylation steps, the first in the liver and the second in the kidneys.
LIQUID VITAMIN D SKIN
Vitamin D from the diet, or from skin synthesis, is biologically inactive. Dietary recommendations typically assume that all of a person's vitamin D is taken by mouth, because sun exposure in the population is variable and recommendations about the amount of sun exposure that is safe are uncertain in view of the skin cancer risk. Mushrooms exposed to ultraviolet light contribute useful amounts of vitamin D 2. and other countries, cow's milk and plant-derived milk substitutes are fortified with vitamin D, as are many breakfast cereals. Only a few foods, such as the flesh of fatty fish, naturally contain significant amounts of vitamin D. Cholecalciferol and ergocalciferol can be ingested from the diet and supplements. The major natural source of the vitamin is synthesis of cholecalciferol in the lower layers of epidermis of the skin, through a photo-chemical reaction of UVB light, from the sun exposure (specifically UVB radiation) or UVB lamps. In humans, the most important compounds in this group are vitamin D 3 ( cholecalciferol) and vitamin D 2 ( ergocalciferol).
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. Rickets, osteoporosis, vitamin D deficiency
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