Group items tagged

Vitamin D is a fat-soluble vitamin that is essential for maintaining normal calcium metabolism (1). Vitamin D3 (cholecalciferol) can be synthesized by humans in the skin upon exposure to ultraviolet-B (UVB) radiation from sunlight, or it can be obtained from the diet. Plants synthesize ergosterol, which is converted to vitamin D2 (ergocalciferol) by ultraviolet light. Vitamin D2 is less active in birds than vitamin D3 and may also be less active in humans (2). When exposure to UVB radiation is insufficient for the synthesis of adequate amounts of vitamin D3 in the skin, adequate intake of vitamin D from the diet is essential for health.

Ecological studies of ultraviolet B, vitamin D and cancer since 2000. Grant WB, Mohr SB. Ann Epidemiol. 2009 Jul;19(7):446-54. Epub 2009 Mar 9. PMID: 19269856 CONCLUSION: These findings provide strong evidence that vitamin D status plays an important role in controlling the outcome of cancer. Support for the UVB-vitamin D-cancer theory is now scientifically strong enough to warrant use of vitamin D in cancer prevention, and as a component of treatment. More research studies would help to explore whether there are benefits beyond the substantial effects that have been observed.

Vitamin D production in human skin occurs only when UV radiation exceeds a threshold. From simulations of UV irradiances, the VitD www page ( http://zardoz.nilu.no/~olaeng/fastrt/VitD.html) computes the daily duration of dermal vitamin D production at midday when UV radiation exceeds the required threshold. The daily duration depends on latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude all of which can be specified by the user

Vitamin D's days of obscurity seem pretty much over. Once just an afterthought to most people-relegated to the sides of milk cartons and the pages of medical texts-it's now on the cusp of becoming a full-fledged disease prevention star. Although vitamin D has long been known as an important factor in bone health, a quickly growing body of evidence now shows that it may also help lower the risk of cancer, heart disease, and even premature death.[1], [2] Not surprisingly, scientists and the public have started to take note, particularly of vitamin D's potential to protect against cancer

Cannell JJ, Vieth R, Umhau JC, Holick MF, Grant WB, Madronich S, Garland CF, Giovannucci E. Epidemic influenza and vitamin D.Epidemiol Infect. 2006 Dec;134(6):1129-40. Epub 2006 Sep 7.PMID: 16959053 doi:10.1017/S0950268806007175

Vieth R.Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety.Am J Clin Nutr. 1999 May;69(5):842-56. Review.PMID: 10232622 [PubMed - indexed for MEDLINE]

A study of Caucasian female twins prompts researchers to ask if public health advice to avoid the sun could be causing low vitamin D levels. Research produced by the Department of Twin Research and Genetic Epidemiology, King's College London, has shown that vitamin D levels are lower in fair-skinned Caucasian women than in Caucasian women with darker skin type. ... "It will be very interesting to see the results of the genetic analysis that the authors propose - especially of polymorphisms [genetic variants] in D binding protein. Variants in this protein associate strongly with skin colour, and also with vitamin D status, so may end up being explanatory.

Ecological Studies Of Ultraviolet B, Vitamin D And Cancer Since 2000. Grant WB, Mohr SB. Ann Epidemiol. 2009 Mar 6. [Epub ahead of print] PMID: 19269856 doi:10.1016/j.annepidem.2008.12.014