It seems every week brings new evidence that vitamin D affects not only our bone strength but a host of other diseases as well. Now, researchers say they have found the "sunshine vitamin" directly influences over 200 genes related to autoimmune diseases.
The study, whose funders include the MS Society of Canada, used new DNA sequencing technology to look for a protein that is activated by vitamin D, called the vitamin D receptor. The receptor attaches itself to DNA and influences what proteins are made from our genetic code.
The researchers found 2,776 binding sites for the vitamin D receptor along the genome. These were unusually concentrated near a number of genes associated with susceptibility to autoimmune conditions such as multiple sclerosis, Crohn's disease, lupus and rheumatoid arthritis. It also clustered along genes linked to cancers such as chronic lymphocytic leukemia and colorectal cancer.
The researchers also showed that vitamin D had a significant effect on the activity of 229 genes including IRF8, previously associated with MS, and PTPN2, associated with Crohn's disease and type 1 diabetes.
"The evidence is accumulating that vitamin D plays a role in rather diverse aspects of health -- far beyond what people generally think of being related to vitamin D, which is bone health," study co-author Prof. George Ebers from the Department of Clinical Neurology at the University of Oxford told Â鶹´«Ã½.
"The evidence now is implicating vitamin D in a number of other things and that is what the study does it catalogues, pinpoints, quantitates the specific genes which are involved."
The results are published in the journal Genome Research.
The lead author of the paper, Dr. Sreeram Ramagopalan from the Wellcome Trust Centre for Human Genetics, said his team's research provides evidence that vitamin D plays an important role in developing susceptibility to a host of diseases.
Ramagopalan added that the findings underscore the serious risks of vitamin D deficiency, especially for individuals who may be genetically predisposed to be sensitive to insufficiency.
He suggested that vitamin D supplementation could be an important preventative measure for these diseases.
"Vitamin D supplements during pregnancy and the early years could have a beneficial effect on a child's health in later life," he said in a statement.
Most of the vitamin D that humans absorb comes from exposing the skin to sunlight. While vitamin D is in some foods, most people cannot absorb enough from diet alone to reach optimal vitamin D levels.
It is estimated that one billion people worldwide do not have sufficient vitamin D. This deficiency is thought to be largely due to insufficient exposure to the sun and in some cases, to poor diet.
