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Vitamin D
(ergocalciferol; cholecalciferol)
DESCRIPTION/FUNCTION
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Vitamin D is classified as a fat-soluble vitamin, but it really is a
prohormone. It is essential for normal growth and development; important for
formation of normal bones and teeth; influences absorption and metabolism of
phosphorus and calcium. Vitamin D is toxic in large quantities, especially if
taken for long periods of time.
DRI (RDA or AI for Adults)
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Under age 51: 200 IU.
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Ages 51-70: 400 IU. Over 70: 600 IU.
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Pregnancy/Lactation: 200 IU.
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1 mcg of cholecalciferol = 40 IU. For example: 5 mcg = 200 IU.
MAJOR SOURCES
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Vitamin D3: cod liver oil, herring oil, pacific oysters, salmon oil,
mackerel, most fish.
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Vitamin D2 is plant derived (a special yeast is irradiated
with UV light).
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Regular
sunlight on un-sunblocked skin can provide the RDA.
MAINTENANCE/THERAPEUTIC RANGE
POSSIBLE THERAPEUTIC APPLICATIONS
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Cancer
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Multiple sclerosis
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Osteoporosis
COMMENTS
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For light-skinned people, exposing the face and arms to bright sunlight for
ten minutes or so, several days per week, is enough to maintain moderately
healthy levels of vitamin D. (Exposure time for light-skinned people living in
mid- to lower latitudes, late spring to early fall, late morning to early
afternoon.) However, because of vitamin D’s anticancer properties, some health professionals are now recommending daily intakes of
1,000 IU or more. For osteoporosis, some doctors prescribe one 50,000 IU pill
per week, in addition to a daily dosage. Also, new research shows that, for osteoporosis, more emphasis
should be placed on vitamin D, and less on calcium.
CAUTIONS
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