how many types of vitamin d are there?
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The two major forms are vitamin D2 and vitamin D3. Vitamin D2 (ergocalciferol) is largely human-made and added to foods, whereas vitamin D3 (cholecalciferol) is synthesized in the skin of humans from 7-dehydrocholesterol and is also consumed in the diet via the intake of animal-based foods.
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The prescription-strength vitamin D is ergocalciferol (Drisdol) and comes in a dose of 50,000 international units (IU), which is usually taken once a week. Most of what is available over the counter is cholecalciferol, which comes in lower doses, 400 or 1,000 IU, which are to be taken once a day.
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While it can also be obtained from dietary sources or supplements, vitamin D3 (cholecalciferol) is synthesized in the human skin from 7-dehydrocholesterol upon exposure to ultraviolet-B (UVB) radiation from sunlight (see the separate article on Vitamin D and Skin Health).
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The D3 form is found in fatty animal-sourced foods, such as fish oil and egg yolk. Your skin also produces it in response to sunlight or ultraviolet light. In contrast, vitamin D2 comes from plants. Interestingly, vitamin D3 appears to be more effective at increasing levels of vitamin D in the blood.
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Vitamin D2 is ergocalciferol and comes from plant-based sources. Vitamin D3 is cholecalciferol and comes from animal-based sources. Both supplements are processed in the body by the liver to 25-hydroxyvitamin D, though vitamin D3 is thought to provide higher levels of 25D.
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Just 10–15 minutes of daily exposure helps manufacture vitamin D throughout the skin. Vitamin D is one of the best vitamins for your skin, along with vitamins C, E, and K. Making sure you get enough vitamins can keep your skin looking healthy and youthful.
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Getting the right vitamins But the sun isn't all bad. Just 10–15 minutes of daily exposure helps manufacture vitamin D throughout the skin. Vitamin D is one of the best vitamins for your skin, along with vitamins C, E, and K. Making sure you get enough vitamins can keep your skin looking healthy and youthful.
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In people whose 25-hydroxyvitamin D (25[OH]D) is <12 ng/mL (30 nmol/L), treatment usually includes 50,000 international units (1250 micrograms) of vitamin D2 or D3 by mouth once or more per week for six to eight weeks, and then 800 to 1000 international units (20 to 25 micrograms), or more, of vitamin D3 daily ...
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Calcitriol (1,25-dihydroxyvitamin D3), the active form of vitamin D, has a half-life of about 15 hours, while calcidiol (25-hydroxyvitamin D3) has a half-life of about 15 days.
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Very few foods in nature contain vitamin D. The flesh of fatty fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources [1,11]. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks.
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What kind of vitamin D is best? The recommended form of vitamin D is vitamin D3 or cholecalciferol. This is the natural form of vitamin D that your body makes from sunlight. Supplements are made from the fat of lambs' wool.
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Classifications of vitamins Vitamins are classified into two groups: Fat soluble vitamins (vitamins A, D, E and K) are soluble in fats and fat solvents.
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Taken in appropriate doses, vitamin D is generally considered safe. However, taking too much vitamin D can be harmful. Children age 9 years and older, adults, and pregnant and breast-feeding women who take more than 4,000 IU a day of vitamin D might experience: Nausea.
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Tests for Vitamin D Deficiency The most accurate way to measure how much vitamin D is in your body is the 25-hydroxy vitamin D blood test. A level of 20 nanograms/milliliter to 50 ng/mL is considered adequate for healthy people. A level less than 12 ng/mL indicates vitamin D deficiency.
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Vitamin D is commonly known as ergocalciferol (Vitamin D2) and cholecalciferol (Vitamin D3). Vitamin D2 and D3 are broken down to their active form, calcitriol, in the body.
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Good food sources of vitamin D include fatty fish such as salmon, especially the wild salmon, tuna, mackerel, mushrooms, eggs and vitamin D fortified foods such as milk (any milk will do--cow, soy, almond, or coconut milk are all fortified). My favorite way to get vitamin D in the winter is from salmon.
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Vitamin E occurs in eight different forms. Those most commonly found in foods and supplements are d-alpha-tocopherol — the synthetic form is d,l-alpha-tocopherol — and gamma-tocopherol. Synthetic alpha-tocopherol is only half as active in the body as the natural form.