Vitamin D

Vitamin D is a vitamin. It can be found in small amounts in a few foods, including fatty fish such as herring, mackerel, sardines and tuna. To make vitamin D more available, it is added to dairy products, juices, and cereals that are then said to be "fortified with vitamin D." But most vitamin D - 80% to 90% of what the body gets - is obtained through exposure to sunlight. Vitamin D can also be made in the laboratory as medicine.
Vitamin D is used for preventing and treating rickets, a disease that is caused by not having enough vitamin D (vitamin D deficiency). Vitamin D is also used for treating weak bones (osteoporosis), bone pain (osteomalacia), bone loss in people with a condition called hyperparathyroidism, and an inherited disease (osteogenesis imperfecta) in which the bones are especially brittle and easily broken. It is also used for preventing falls and fractures in people at risk for osteoporosis, and preventing low calcium and bone loss (renal osteodystrophy) in people with kidney failure.

Vitamin D is used for conditions of the heart and blood vessels, including high blood pressure and high cholesterol. It is also used for diabetes, obesity, muscle weakness, multiple sclerosis, rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), asthma, bronchitis, premenstrual syndrome (PMS), and tooth and gum disease.
Some people use vitamin D for skin conditions including vitiligo, scleroderma, psoriasis, actinic keratosis, and lupus vulgaris. It is also used for boosting the immune system, preventing autoimmune diseases, and preventing cancer because vitamin D is involved in regulating the levels of minerals such as phosphorous and calcium, it is used for conditions caused by low levels of phosphorous (familial hypophosphatemia and Fanconi syndrome) and low levels of calcium (hypoparathyroidism and pseudohypoparathyroidism).
Vitamin D in forms known as calcitriol or calcipotriene is applied directly to the skin for a particular type of psoriasis.

What is Vitamin D ?
Vitamin D is a fat-soluble vitamin that helps the body absorb calcium. Fat-soluble vitamins are stored in the body's fatty tissue. Vitamin D is required for the regulation of the minerals calcium and phosphorus found in the body. It also plays an important role in maintaining proper bone structure.

Sun exposure is an easy, reliable way for most people to get vitamin D. Exposure of the hands, face, arms, and legs to sunlight two to three times a week for about one-fourth of the time it would take to develop a mild sunburn will cause the skin to produce enough vitamin D. The necessary exposure time varies with age, skin type, season, time of day, etc.

It’s amazing how quickly adequate levels of vitamin D can be restored by sunlight. Just 6 days of casual sunlight exposure without sunscreen can make up for 49 days of no sunlight exposure. Body fat acts like a kind of storage battery for vitamin D. During periods of sunlight, vitamin D is stored in fatty fat and then released when sunlight is gone.

Nevertheless, vitamin D deficiency is more common than you might expect. People who don’t get enough sun, especially people living in Canada and the northern half of the US, are especially at risk. Vitamin D deficiency also occurs even in sunny climates, possibly because people are staying indoors more, covering up when outside, or using sunscreens consistently these days to reduce skin cancer risk.

Older people are also at risk for vitamin D deficiency. They are less likely to spend time in the sun, have fewer "receptors" in their skin that convert sunlight to vitamin D, may not get vitamin D in their diet, may have trouble absorbing vitamin D even if they do get it in their diet, and may have more trouble converting dietary vitamin D to a useful form due to aging kidneys. In fact, the risk for vitamin D deficiency in people over 65 years of age is very high.

Vitamin D supplements may be necessary for older people, people living in northern latitudes, and for dark-skinned people who need extra time in the sun, but don’t get it.

Where it is found
Vitamin D is found in the following foods:
Dairy products
Fortified milk (all milk in the U.S. is fortified with vitamin D)
Fortified cereals

See Vitamin D related videos:
video icon The Benefits Of Vitamin D (video module - 7.02 minutes)
video icon Benefits of Vitamin D arw(video module - 3.33 minutes)
Product related PDF file
Fact Sheet On Vitamin D
The Many Uses Of Vitamin D
Vitamin D

Benefits / uses
arw Treating conditions that cause weak and painful bones (osteomalacia).

arw Low levels of phosphate in the blood (familial hypophosphatemia).

arw Low levels of phosphate in the blood due to a disease called Fanconi syndrome.

arw Psoriasis (with a specialized prescription-only form of vitamin D).

arw Low blood calcium levels because of a low parathyroid thyroid hormone levels.

arw Helping prevent low calcium and bone loss (renal osteodystrophy) in people with kidney failure.

arw Rickets.

arw Vitamin D deficiency.

arw Treating osteoporosis (weak bones). Taking a specific form of vitamin D called cholecalciferol (vitamin D3) along with calcium seems to help prevent bone loss and bone breaks.

arw Preventing falls in older people. Researchers noticed that people who don’t have enough vitamin D tend to fall more often than other people. They found that taking a vitamin D supplement reduces the risk of falling by up to 22%. Higher doses of vitamin D are more effective than lower doses. One study found that taking 800 IU of vitamin D reduced the risk of falling, but lower doses didn’t. Also, vitamin D, in combination with calcium, but not calcium alone, may prevent falls by decreasing body sway and blood pressure. This combination prevents more falls in women than men.

arw Reducing bone loss in people taking drugs called corticosteroids.

arw Reducing the risk of multiple sclerosis (MS). Studies show taking vitamin D seems to reduce women’s risk of getting MS by up to 40%. Taking at least 400 IU per day, the amount typically found in a multivitamin supplement, seems to work the best.

arw Preventing cancer. Some research shows that people who take a high-dose vitamin D supplement plus calcium might have a lower chance of developing cancer of any type.

arw Weight loss. Women taking calcium plus vitamin D are more likely to lose weight and maintain their weight. But this benefit is mainly in women who didn’t get enough calcium before they started taking supplements.

arw Flu. Some research in school aged children show that taking a vitamin D supplement during winter might reduce the chance of getting seasonal flu.

arw Reducing the risk of rheumatoid arthritis in older women.

arw Reducing bone loss in women with a condition called hyperparathyroidism.

arw Preventing tooth loss in the elderly.

When to take /types to take
Vitamin D supplements are best taken with meal.
Ergocalciferol (D2) is a form of Vitamin D prepared from special strains of yeast. This is the vegetarian form of Vitamin D. Cholecalciferol (D3) is prepared from cholesterol of wool grease washed from the sheared wool of sheep. Fish liver oil provides vitamin D in the form of cholecalciferol. These are the three commercially available forms of vitamin D.

Vitamin D is also known as the "sunshine vitamin" because the body manufactures the vitamin after being exposed to sunshine. Ten to 15 minutes of sunshine 3 times weekly is enough to produce the body's requirement of vitamin D. However, many people living in sunny climates still do not make enough vitamin D and need more from their diet or supplementation.

For preventing osteoporosis and fractures: 400-1000 IU per day has been used for older adults. Some experts recommended higher doses of 1000-2000 IU daily.

arw For preventing falls: 800-1000 IU/day has been used in combination with calcium 1000-1200 mg/day.
arw For preventing multiple sclerosis (MS): long-term consumption of at least 400 IU per day, mainly in the form of a multivitamin supplement, has been used.
arw For preventing all cancer types: calcium 1400-1500 mg/day plus vitamin D3 (cholecalciferol) 1100 IU/day in postmenopausal women has been used.
arw For muscle pain caused by medications called "statins": vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol) 50,000 units once a week or 400 IU daily.
arw For preventing the flu: vitamin D (cholecalciferol) 1200 IU daily.

Most vitamin supplements contain only 400 IU (10 mcg) vitamin D.
The Institute of Medicine publishes recommended daily allowance (RDA), which is an estimate of the amount of vitamin D that meets the needs of most people in the population. The current RDA was set in 2010. The RDA varies based on age as follows: 1-70 years of age, 600 IU daily; 71 years and older, 800 IU daily; pregnant and lactating women, 600 IU daily. For infants ages 0-12 months, an adequate intake (AI) level of 400 IU is recommended.

Some organizations are recommending higher amounts. In 2008, the American Academy of Pediatrics increased the recommended minimum daily intake of vitamin D to 400 IU daily for all infants and children, including adolescents. Parents should not use vitamin D liquids dosed as 400 IU/drop. Giving one dropperful or mL by mistake can deliver 10,000 IU/day. The US Food and Drug Administration (FDA) will force companies to provide no more than 400 IU per dropperful in the future.

The National Osteoporosis Foundation recommends vitamin D 400 IU to 800 IU daily for adults under age 50, and 800 IU to 1000 IU daily for older adults.
The North American Menopause Society recommends 700 IU to 800 IU daily for women at risk of deficiency due to low sun (e.g., homebound, northern latitude) exposure.

Guidelines from the Osteoporosis Society of Canada recommend vitamin D 400 IU per day for people up to age 50, and 800 IU per day for people over 50. Osteoporosis Canada now recommends 400-1000 IU daily for adults under the age of 50 years and 800-2000 IU daily for adults over the age of 50 years.
The Canadian Cancer Society recommends 1000 IU/day during the fall and winter for adults in Canada. For those with a higher risk of having low vitamin D levels, this dose should be taken year round. This includes people who have dark skin, usually wear clothing that covers most of their skin, and people who are older or who don't go outside often.

Possible Side effects / Precautions / Possible Interactions:
Too much vitamin D can make the intestines absorb too much calcium. This may cause high levels of calcium in the blood. High blood calcium can lead to calcium deposits in soft tissues such as the heart and lungs. This can reduce their ability to function. Kidney stones, vomiting, and muscle weakness may also occur if you have too much vitamin D.

Research studies / References

arw Walter F., PhD. Boron (2003). "The Parathyroid Glands and Vitamin F". Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. p. 1094. ISBN 978-1-4160-2328-9.

arw DRI, Dietary reference intakes: for calcium, phosphorus, magnesium, vitamin D, and fluoride. Washington, D.C: National Academy Press. 1997. p. 250. ISBN 0-309-06350-7.

arw a b Bowerman, Susan (2008-03-31). "If mushrooms see the light". Los Angeles Times. Retrieved 2010-03-25.

arw Adams, J. S.; Hewison, M. (2010). "Update in Vitamin D". Journal of Clinical Endocrinology & Metabolism 95 (2): 471-8. doi:10.1210/jc.2009-1773. PMC 2840860. PMID 20133466.

arw a b c d e f g "Dietary Supplement Fact Sheet: Vitamin D". Office of Dietary Supplements (ODS). National Institutes of Health (NIH). Retrieved 2010-04-11.

arw Dorland's Illustrated Medical Dictionary, under Vitamin (Table of Vitamins)

arw History of Vitamin D University of California, Riverside, Vitamin D Workshop.

arw a b c About Vitamin D Including Sections: History, Nutrition, Chemistry, Biochemistry, and Diseases. University of California Riverside

arw "Vitamin D". Mayo Clinic

arw a b Houghton LA, Vieth R (October 2006). "The case against ergocalciferol (vitamin D2) as a vitamin supplement". The American Journal of Clinical Nutrition 84 (4): 694-7. PMID 17023693.

arw a b Holick, MF (2004). "Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis". The American Journal of Clinical Nutrition 79 (3): 362-71. PMID 14985208.

arw Hume, Eleanor Margaret; Lucas, Nathaniel Sampson; Smith, Hannah Henderson (1927). "On the Absorption of Vitamin D from the Skin". Biochemical Journal 21 (2): 362-367. PMC 1251921. PMID 16743844.

arw a b c Holick MF (March 1995). "Environmental factors that influence the cutaneous production of vitamin D". The American Journal of Clinical Nutrition 61 (3 Suppl): 638S-645S. PMID 7879731.

arw Crissey, SD; Ange, KD; Jacobsen, KL; Slifka, KA; Bowen, PE; Stacewicz-Sapuntzakis, M; Langman, CB; Sadler, W et al. (2003). "Serum concentrations of lipids, vitamin D metabolites, retinol, retinyl esters, tocopherols and selected carotenoids in twelve captive wild felid species at four zoos". The Journal of nutrition 133 (1): 160-6. PMID 12514284.

arw Yahav, S; Buffenstein, R (1993). "Cholecalciferol supplementation alters gut function and improves digestibility in an underground inhabitant, the naked mole rat (Heterocephalus glaber), when fed on a carrot diet". The British journal of nutrition 69 (1): 233-41. doi:10.1079/BJN19930025. PMID 8384476.

arw Csiszar, A; Labinskyy, N; Orosz, Z; Xiangmin, Z; Buffenstein, R; Ungvari, Z (2007). "Vascular aging in the longest-living rodent, the naked mole rat". American journal of physiology. Heart and circulatory physiology 293 (2): H919-27. doi:10.1152/ajpheart.01287.2006. PMID 17468332.

arw Buffenstein, R (2008). "Negligible senescence in the longest living rodent, the naked mole-rat: insights from a successfully aging species". Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology 178 (4): 439-45. doi:10.1007/s00360-007-0237-5. PMID 18180931.

arw Stout, Sam D.; Agarwal, Sabrina C.; Stout, Samuel D. (2003). Bone loss and osteoporosis: an anthropological perspective. New York: Kluwer Academic/Plenum Publishers. ISBN 0-306-47767-X.

arw "Unraveling The Enigma Of Vitamin D" United States National Academy of Sciences

arw "Adolf Windaus - Biography". 2010-03-25. Retrieved 2010-03-25.

arw Arvids A. Ziedonis; Mowery, David C.; Nelson, Richard R.; Bhaven N. Sampat (2004). Ivory tower and industrial innovation: university-industry technology transfer before and after the Bayh-Dole Act in the United States. Stanford, Calif: Stanford Business Books. pp. 39-40. ISBN 0-8047-4920-5.

arw Marshall, James (2005). Elbridge A. Stuart Founder of the Carnation Company. Kessinger Publishing. p. 235. ISBN 978-1417988839.

arw Cheng JB, Levine MA, Bell NH, Mangelsdorf DJ, Russell DW (18 May 2004). "Genetic evidence that the human CYP2R1 enzyme is a key vitamin D

arw 25-hydroxylase". Proc Natl Acad Sci U S A 101 (20): 7711-7715. doi:10.1073/pnas.0402490101. PMC 419671. PMID 15128933.

arw a b c Holick, MF (2004). "Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease". The American Journal of Clinical Nutrition 80 (6 Suppl): 1678S-88S. PMID 15585788.

arw Puchacz E, Stumpf WE, Stachowiak EK, Stachowiak MK (February 1996). "Vitamin D increases expression of the tyrosine hydroxylase gene in adrenal medullary cells". Brain Res Mol Brain Res 36 (1): 193-6. doi:10.1016/0169-328X(95)00314-I. PMID 9011759.