Vitamin D's possible effect on our genes

Researchers from the UK and Canada have identified 229 human genes that are influenced by changes in vitamin D levels. Several of these genes are implicated in cancers and autoimmune diseases such as multiple sclerosis (MS), Type 1 diabetes, lupus, and rheumatoid arthritis.

The vitamin D receptor (VDR), a protein activated by vitamin D, binds to specific sites in the DNA, where it can affect the activity or expression of nearby genes.

Scientists mapped the sites of VDR binding to the genome and identified 2,776 sites, using a technique called ChIP-seq (chromatin immunoprecipitation-sequencing). Human cells were treated with calcitriol, the active form of vitamin D, and DNA fragments bound to the VDR were isolated and then sequenced.

Professor George Ebers, Action Medical Research Professor of Clinical Neurology at Oxford, explained: 'We screened the whole genome and found all the sites where vitamin D binds. The evidence is now quite solid that not only is there binding but we've been able to show that it actually affects the functioning of the gene. It's not just sticking to that region, it's actually altering gene expression'.

'Our study shows quite dramatically the wide-ranging influence that vitamin D exerts over our health', added Dr Andreas Heger from the MRC Functional Genomics Unit at Oxford, one of the lead authors of the study.

It is estimated that one billion people worldwide could be suffering from deficiencies in vitamin D. Its main source in the body comes from exposing the skin to sunlight, and in some cases a diet of oily fish, eggs, and some fortified foods like cereal. A lack of vitamin D can affect bone development, leading to rickets; whereas in pregnant mothers, poor bone health can be fatal to both mother and child at birth.

'Vitamin D supplements during pregnancy and the early years could have a beneficial effect on a child's health in later life', highlighted the lead author, Dr Sreeram Ramagopalan from the Wellcome Trust Centre for Human Genetics, Oxford.

This study, along with further research, could explain why vitamin D plays such an important role in a wide range of diseases, and why people who are native to Northern Latitudes have over many generations evolved a lighter skin colour.

Lastly, these findings could also be used to assess the guidelines for recommended vitamin D intake.

The research is published in the journal Genome Research.