world doctors
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Vitamin D: Health Benefits, Facts and Research
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The greatest international website of world doctors:
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Vitamin D, also known as the sunshine vitamin, can be produced in the body with mild sun
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exposure or consumed in food or supplements.
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Adequate vitamin D intake is important for the regulation of calcium and phosphorus absorption,
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maintenance of healthy bones and teeth, and is suggested to supply a protective effect against
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multiple diseases and conditions such as cancer, type 1 diabetes and multiple sclerosis.
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Vitamin D has multiple roles in the body, helping to:
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* Maintain the health of bones and teeth
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* Support the health of the immune system, brain and nervous system
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* Regulate insulin levels and aid diabetes management
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* Support lung function and cardiovascular health
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* Influence the expression of genes involved in cancer development.
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In spite of the name, vitamin D is considered a pro-hormone and not actually a vitamin. This
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is because the body is capable of producing its own vitamin D through the action of sunlight
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on the skin, while vitamins are nutrients that cannot be synthesized by the body and must be
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acquired through the diet or supplements.
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It is estimated that sensible sun exposure on bare skin for 5-10 minutes 2-3 times per week
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allows the body the ability to produce sufficient vitamin D, but vitamin D has a half-life of
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only two weeks, meaning that stores can run low, especially in winter. Recent studies have
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suggested that up to 50% of adults and children worldwide are vitamin D deficient. There
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are several likely factors contributing to vitamin D deficiency, which will be looked at further
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in this article.
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Vitamin D is produced when sunlight converts cholesterol on the skin into calciol (vitamin
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D3). Vitamin D3 is then converted into calcidiol (25-hydroxyvitamin D3) in the liver. The
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kidneys then convert calcidiol into the active form of vitamin D, called calcitriol (1,25-
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hydroxyvitamin D3). As such, statins and other medications or supplements that inhibit
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cholesterol synthesis, liver function or kidney function can impair the synthesis of vitamin D.
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Fast facts on vitamin D
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Here are some key points about vitamin D. More detail and supporting information is in the
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main article.
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* Vitamin D's primary role is to support the development and maintenance of bones and teeth.
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* A fair-skinned person with full body exposure to the sun can synthesize up to 20,000 IU of
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vitamin D3 in 20 minutes.
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* Vitamin D deficiency is common, especially in the elderly, infants, people with dark skin and
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people living at higher latitudes or who get little sun exposure.
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* Vitamin D deficiency has been seen in up to 80% of hip fracture patients.
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* 800IU of vitamin D per day reduces the risk of fracture by 20% in the elderly and decreases
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the risk of falls.
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* The metabolism of vitamin D may be affected by some medications, including barbiturates,
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phenobarbital, dilantin, isoniazid and statin drugs.
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