Vitamin D continues to make the news. This time a study (1) has mapped where vitamin D interacts with our DNA. Scientists have found that there are over 200 genes which are directly influenced by vitamin D, thus highlighting the extent to which vitamin D deficiency may increase our susceptibility to a wide range of diseases.
The study scientists used a new type of DNA sequencing technology to create a map of vitamin D receptor binding across the genome. The vitamin D receptor is a protein that is activated by vitamin D, which attaches itself to our DNA and in this way influences what proteins are made from our genetic code (2).
There has been some indication by experts that up to half the world’s population has lower than optimal levels of vitamin D, and that about one billion people are actually vitamin D deficient. The problem seems to be getting worse as people spend more and more time indoors. As well as being a well-known risk factor for poor bone development and rickets, there is a growing body of evidence that vitamin D deficiency also increases an individual’s susceptibility to autoimmune conditions such as multiple sclerosis (MS), rheumatoid arthritis and type 1 diabetes, as well as certain cancers and even brain conditions such as dementia (2).
The researchers found that there were over 2000 binding sites for the vitamin D receptor along the length of the human genome. These were found to be unusually concentrated near a number of genes associated with susceptibility to autoimmune conditions such as MS, Crohn’s disease, systemic lupus erythematosus (or ‘lupus’) and rheumatoid arthritis, and to cancers such as chronic lymphocytic leukaemia and colorectal cancer (2). The researchers also discovered that vitamin D had a significant effect on the activity of 229 genes including those which had previously been linked with multiple sclerosis (MS), Crohn’s disease and type 1 diabetes (1,2).
“Our study shows quite dramatically the wide-ranging influence that vitamin D exerts over our health,” said one of the study researchers, Dr Andreas Heger, in a press release (2). Another of the authors, Dr Sreeram Ramagopalan, said (2) “There is now evidence supporting a role for vitamin D in susceptibility to a host of diseases. Vitamin D supplements during pregnancy and the early years could have a beneficial effect on a child’s health in later life. Some countries such as France have instituted this as a routine public health measure.”
The study again highlights the importance of vitamin D for human health. The study does not give any conclusive evidence for the use of supplements in disease prevention but certainly points the way for further research in the field of vitamin D supplementation. Most vitamin D is made by the body from the action of sunlight on the skin. Very small amounts of vitamin D can be found in foods such as eggs and oily fish e.g. salmon, mackerel and sardines. As mentioned in my previous blog posts on vitamin D there are no definitive studies on the optimal daily dose of vitamin D for health. Some experts recommend around 2000iu daily with others calling for higher doses. Always check with your medical doctor prior to taking any supplements.
(1) Ramagopalan SV et al. 2010. A ChIP-seq-defined genome-wide map of vitamin D receptor binding: Associations with disease and evolution. Genome Research, 2010; Published in Advance August 24 DOI: 10.1101/gr.107920.110
(2)Press release. Wellcome Trust (2010, August 24). Vitamin D found to influence over 200 genes, highlighting links to disease. ScienceDaily. Retrieved August 25, 2010, from http://www.sciencedaily.com /releases/2010/08/100823172327.htm
Written by Ani Kowal