Vitamin D has long presented something of an enigma when it comes to the wide variety of diseases it might prevent.
Research has linked not having enough of the sunshine vitamin to ailments as unalike as colon cancer, multiple sclerosis and rickets.
The big question: How could one nutrient have an impact on such seemingly unrelated diseases?
Now, a team of researchers at Oxford University believes it has the answer. The scientists have found that the human genome just bristles with places where vitamin D receptor can be utilized, indicating it has a huge effect on DNA.
"Our study shows quite dramatically the wide-ranging influence that vitamin D exerts over our health," says Andreas Heger, a professor at the MRC Functional Genomics Unit at Oxford and one of the study's lead authors.
According to the team's calculations, there are nearly 2,800 binding sites for the vitamin D receptor across the length of the genome, the complete package of an individual's DNA or hereditary information. Vitamin D also has a significant impact on the activity of 229 genes, suggesting that its many genetic influences are a key to understanding why the nutrient may play a role in everything from cancer to bone disease.
Details of the research, which was funded in part by the Canadian MS Foundation and the Wellcome Trust, a British-based charity, is contained in a paper published Monday in the journal Genome Research.
Among some of the other conditions researchers have linked to vitamin D insufficiency are dementia, breast cancer and a number of autoimmune ailments including multiple sclerosis, Type 1 diabetes and Crohn's disease.
The Oxford study found that vitamin D binding sites were concentrated near genes that raise the susceptibility to MS, lymphocytic leukemia, lupus and colorectal cancer.
"There is now evidence supporting a role for vitamin D in susceptibility to a host of diseases," said Sreeram Ramagopalan, a researcher at the Wellcome Trust Centre for Human Genetics and another of the study authors.
Most of the vitamin D in people comes from exposure to sunlight, although it can also be taken as a supplement and is found in some foods, such as oily coldwater fish.
The amount of vitamin D needed for optimal health, as well as the many disease-prevention claims for the nutrient, are currently under review by an expert panel reporting to Health Canada and the U.S. Department of Health. Results are expected later in the fall.