vitamin D req't AGAIN

[Guest guest]

I suggest those concerned with vit D read:http://www.ajcn.org/cgi/content/full/69/5/842#R16

the refs ate the end of doc contain a lot of useful info.

And the 53 articles cited by this article at the very end present the state of knowledge (or lack of) and

http://darwin.nap.edu/books/0309085373/html/1320.html

shows the RDA at 9 yrs past the first article.

Many of these are full text, and by the time I read all these, two things I THINK :

"The evidence suggests that efforts to improve vitamin D status, for example by vitamin D supplementation, could reduce cancer incidence and mortality at low cost, with few or no adverse effects."

"Vitamin D status differs by latitude and race, with residents of the northeastern United States and individuals with more skin pigmentation being at increased risk of deficiency. "

The first I don't have full text, but perhaps this one sums up the cancer story:

Journal of the National Cancer Institute

Volume 96(10), 19 May 2004, pp 735-736

"“There’s more to this vitamin D story,” said Lieberman, M.D., program director of the Prostate and Urologic Cancer Research Group in the National Cancer Institute’s Division of Cancer Prevention. “It is fascinating as a molecule. It’s been shown to be antiproliferative, proapoptotic, antiangiogenic. In prostate cancer, its effects appear to be on the cell cycle, stopping growth by upregulating [the tumor suppressor] p21.”

He is quick to add, “Yet we don’t have a bit of data that I could show you to say it will work as a preventative.” Most of the evidence is from ecologic, epidemiologic, and laboratory studies of cancers of the prostate, breast, colon, and pancreas. For now, the available studies in patients are treatment trials suggesting that vitamin D may heighten the effects of chemotherapy or radiation. There have been few studies of vitamin D as a cancer chemopreventive.

"The American Academy of Dermatology is not moved. A July 2003 press release stated, “It is dangerous to mislead the public into thinking that sunlight is a safe and effective ‘cure’ for other health conditions.” AAD president L. Cornelison Jr., M.D., suggested that people take a multivitamin or drink a few glasses of vitamin D–fortified milk every day, adding, “the dangers of exposing oneself to carcinogenic UV light from the sun, even for a few minutes, are firmly established.”

“Is vitamin D insufficiency common? Yes. Is it likely a contributing factor to prostate, breast, colon, and maybe some other cancers? Yes,” said Schwartz. “Am I saying ‘get thee to a skin tannery’? No.”

“I’m not sure how the sun-versus-supplement issue will play out,” said Baron, whose study will include a questionnaire on sun exposure. Welsh added, “It’s still too early to know the right thing to do.”

AND:

"Abstract

Vitamin D deficiency is more common than realized. It is making a resurgence in neonates and is common in black patients and older adults. Vitamin D deficiency not only causes generalized muscle weakness, muscle aches, and bone aches and pains but also can precipitate and exacerbate osteoporosis and cause osteomalacia. Although the kidney plays a critical role in producing 1,25-dihydroxyvitamin D, which is important for regulating calcium, phosphorus, and bone metabolism, it is now recognized that a wide variety of other tissues have the enzymatic machinery to produce 1,25-dihydroxyvitamin D. Vitamin D receptors are common in most tissues in the body, and the new revelation that many tissues produce 1,25-dihydroxyvitamin D suggests a new important role for this hormone in helping to maintain good health throughout life.

Probably the best description of vit D pathways is in:

Holick, F. PhD, MD Vitamin D: the underappreciated D-lightful hormone that is important for skeletal and cellular health. Current Opinion in Endocrinology & Diabetes. 9(1):87-98, February 2002.

"Thus, in the absence of sufficient exposure to sunlight at least 1000 IU of vitamin D/d is probably required to maintain a healthy level of 25 (OH)D "

This article suggests to me if I was concerned about D status, I would get a blood test:

Holick, F. MD, PHD Vitamin D: Important for Prevention of Osteoporosis, Cardiovascular Heart Disease, Type 1 Diabetes, Autoimmune Diseases, and Some Cancers. Southern Medical Journal. 98(10):1024-1026, October 2005.

"

Abstract:

Vitamin D is very important for overall health and well-being. A major source of vitamin D comes from exposure to sunlight. Measurement of 25-hydroxyvitamin D in the blood and not 1,25-dihydroxyvitamin D is used to determine vitamin D status. A blood level of 25-hydroxyvitamin D of at least 20 ng/mL is considered to be vitamin D sufficient. Vitamin D deficiency increases the risk of many common cancers, multiple sclerosis, rheumatoid arthritis, hypertension, cardiovascular heart disease, and type I diabetes."

Key Points

* Ninety percent or more of our vitamin D requirement comes from exposure to sunlight. Without sun exposure, 1,000 IU of vitamin D per day is required."

I went thru this a cupla months ago and satisfied myself I had no worry, but I added 800 IU to try it. The result was I think there may be a selection problem in which pill to take. I notice they are adding D3 to the orange juice calling it 25% of RDA.

I must stick with the RDA until the powers sort it out.

Regards.