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Meg Mangin R.N.
Research Team
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Posted: Sat May 21st, 2005 21:45 |
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Why are so many doctors ordering vitamin D supplementation?
Industrial forces that have a financial conflict of interest are promoting increased vitamin D supplementation. To increase the sales of vitamin D, they have called on self-appointed vitamin D experts to raise the level of 25-D that is accepted as normal. The studies their claims are based on are seriously flawed and/or based on an outdated understanding of vitamin D.
Belinda Fenter, in a recent post, provided an excellent explanation:
"It used to be accepted that vitamin D was synthesized via the skin, and then metabolized via the liver and kidneys. Now we know that human skin can completely synthesize the active hormone D, 1,25-dihydroxycholecalciferol, independent of other organs. http://tinyurl.com/65nrc While there is substantial evidence for other extra-renal sources of hormone 1,25-D, it has been known for decades that activated macrophages produce 1,25-D in diseases such as sarcoidosis.
The vitamin D used by the body (1,25-D) comes mostly (90 to 100%)from exposure to sunlight. http://tinyurl.com/4z25e Ten to fifteen minutes of sun exposure two times per week to the face, arms, hands, or back is enough exposure to provide an adequate amount. People can get that in only a fraction of the amount of time they spend driving each week.
We know now that hormone D (1,25-D) activates the immune system. However, the increased use of nutritional vitamin D (25-D) depresses the immune systems of people with immune disease who can be made ill by additional vitamin D
Until we standardize the clinical evaluation of vitamin D metabolites, both 1,25-dihydroxycholecalciferol D and the inactive precursor, 25-dihydroxyvitamin D, we have no idea who actually needs supplemental vitamin D and who has dysregulated vitamin D metabolism, resulting in their suffering excess production of the biologically active metabolite and all the impact of this hormone, which includes activation of the immune macrophage system. http://tinyurl.com/6gbgq
Regarding nutritional sources of vitamin D:
- There is no Recommended Daily Allowance (RDA) for vitamin D, because it is endogenously produced by humans in the presence of a few minutes of sunlight.
- The alternative Recommended Dietary Intake (RDI) of nutritional vitamin D is based on the absence of adequate sunlight. http://www.iom.edu/Object.File/Master/7/296/0.pdf
- When studies of dietary needs for vitamin D are conducted, people with diseases that result in dysregulated vitamin D metabolism (such as sarcoidosis) may be excluded. One example is the Food Standards Agency's Expert Group on Vitamin and Minerals: Safe Upper Levels for Vitamins and Minerals May 2003
http://www.food.gov.uk/multimedia/pdfs/vitmin2003.pdf
That report noted, "Excessive vitamin D intake may lead to hypercalcaemia and hypercalciurua. Vitamin D promotes the absorption of calcium and the resorption of bone resulting in the deposition of calcium in soft tissues, diffuse demineralisation of bones and irreversible renal and cardiovascular toxicity. It has long been known that (as the report continues), "Patients with sarcoidosis are abnormally sensitive to vitamin D, due to uncontrolled conversion of the vitamin to its active form in the granulomatous tissue."
Why has there been so much detection of low 25-D, called "vitamin D deficiency," when people consume vitamins and foods containing supplemented vitamin D? Uncontrolled conversion of vitamin D to its active form, hormone 1,25-D, is rarely investigated in any research of vitamin D deficiency. Based on results that have been reported to our websites, we believe this uncontrolled conversion of 25-D to 1,25-D is a common cause of measured 25-D "deficiency," and the underlying reason is the existance of Th1 disease.
Studies have shown that nutritional vitamin D can be toxic to vascular tissues. http://tinyurl.com/45he3 http://tinyurl.com/44kb4 Vitamin D has been used to induce an animal model of arthrosclerosis in research: http://tinyurl.com/664sv
Too much vitamin D can result in illness ranging from dental changes http://tinyurl.com/66e98,
to bone loss http://tinyurl.com/4m9au or even death.http://tinyurl.com/4cfsg
The standard practice, in assessing vitamin D status, has been to evaluate only serum 25-D, which is the inactive metabolite. The best way to know whether sunlight and vitamin D would be dangerous is to test the two major vitamin D metabolites (25-D and hormone 1,25-D) to detect any evidence of dysregulated vitamin D metabolism."
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The science is not an issue
There are a lot of research groups which understand the immunosuppression. The science is not an issue. We primarily have to deal with one or two journalists who are being paid by the Vitamin D Council to spread disinformation. And the clinicians who are proliferating worthless 'epidemiologoical studies' while trying to figure out what is actually happening. They should instead be trying to get their heads around the scientific complexities.
The epidemic of chronic disease is getting bad enough that questions are now being asked. At the DMM2007 Conference we discussed World Health (or lack of it), both in formal sessions, and in the hallways. It will take time to get the message out, but at least we already know the answer.
..Trevor..
Further information can be found in these FAQs:
Can my Vitamin 25-D go too low?
My 25-D is low. Should I be concerned about osteoporosis?
Please share this information with your doctor so s/he can understand the biases that are influencing clinicians' thinking about vitamin D.
Last edited on Sun Jul 15th, 2007 01:49 by Meg Mangin R.N.
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