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Vitamin D Deficiency Study Raises New Questions About Disease And Supplements

ScienceDaily (Jan. 27, 2008) — Low blood levels of vitamin D have long been

associated with disease, and the assumption has been that vitamin D supplements

may protect against disease. However, this new research demonstrates that

ingested vitamin D is immunosuppressive and that low blood levels of vitamin D

may be actually a result of the disease process. Supplementation may make the

disease worse.

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In a new report Trevor Marshall, Ph.D., professor at Australia’s Murdoch

University School of Biological Medicine and Biotechnology, explains how

increased vitamin D intake affects much more than just nutrition or bone health.

The paper explains how the Vitamin D Nuclear Receptor (VDR) acts in the

repression or transcription of hundreds of genes, including genes associated

with diseases ranging from cancers to multiple sclerosis.

" The VDR is at the heart of innate immunity, being responsible for expression

of most of the antimicrobial peptides, which are the body’s ultimate response to

infection, " Marshall said.

" Molecular biology is now forcing us to re-think the idea that a low measured

value of vitamin D means we simply must add more to our diet. Supplemental

vitamin D has been used for decades, and yet the epidemics of chronic disease,

such as heart disease and obesity, are just getting worse. "

" Our disease model has shown us why low levels of vitamin D are observed in

association with major and chronic illness, " Marshall added. " Vitamin D is a

secosteroid hormone, and the body regulates the production of all it needs. In

fact, the use of supplements can be harmful, because they suppress the immune

system so that the body cannot fight disease and infection effectively. "

Marshall's research has demonstrated how ingested vitamin D can actually block

VDR activation, the opposite effect to that of Sunshine. Instead of a positive

effect on gene expression, Marshall reported that his own work, as well as the

work of others, shows that quite nominal doses of ingested vitamin D can

suppress the proper operation of the immune system. It is a different

metabolite, a secosteroid hormone called 1,25-dihydroxyvitamin D, which

activates the VDR to regulate the expression of the genes. Under conditions that

exist in infection or inflammation, the body automatically regulates its

production of all the vitamin D metabolites, including 25-hydroxyvitamin D, the

metabolite which is usually measured to indicate vitamin D status.

Vitamin D deficiency, long interpreted as a cause of disease, is more likely

the result of the disease process, and increasing intake of vitamin D often

makes the disease worse. " Dysregulation of vitamin D has been observed in many

chronic diseases, including many thought to be autoimmune, " said J.C.

Waterhouse, Ph.D., lead author of a book chapter on vitamin D and chronic

disease.

" We have found that vitamin D supplementation, even at levels many consider

desirable, interferes with recovery in these patients. "

" We need to discard the notion that vitamin D affects a disease state in a

simple way, " Marshall said. " Vitamin D affects the expression of over 1,000

genes, so we should not expect a simplistic cause and effect between vitamin D

supplementation and disease. The comprehensive studies are just not showing that

supplementary vitamin D makes people healthier. "

Journal reference: Marshall TG. Vitamin D discovery outpaces FDA decision

making. Bioessays. 2008 Jan 15;30(2):173-182 [Epub ahead of print] Online ISSN:

1521-1878 Print ISSN: 0265-9247 PMID: 18200565

Adapted from materials provided by Autoimmunity Research Foundation, via

AlphaGalileo.

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