TUESDAY, Aug. 24 (HealthDay News) -- Scientists have discovered a link between vitamin D and genes related to autoimmune diseases and cancer.

The finding may explain why vitamin D deficiency is a risk factor for a number of serious illnesses, including multiple sclerosis, type 1 diabetes and rheumatoid arthritis, according to researchers from the United Kingdom and Canada.

In the study, Sreeram Ramagopalan of Oxford University and colleagues noted there is a growing amount of evidence that vitamin D deficiency is a risk factor for a wide range of diseases, but it's not known exactly how vitamin D is involved. It has been suspected that genetics may contribute to this connection.

Vitamin D has an effect on genes through the vitamin D receptor, which binds to specific locations on the human genome to influence gene expression (the process by which a gene's information is converted into the structures operating in a cell). In this study, the researchers mapped sites of vitamin D receptor binding -- information that can be used to identify disease-related genes that might be influenced by vitamin D.

The investigators found that vitamin D receptor binding is significantly enhanced in regions of the human genome associated with several common autoimmune diseases, such as multiple sclerosis, type 1 diabetes and Crohn's disease, and in regions associated with cancers such as leukemia and colorectal cancer.

The findings, published in the Aug. 23 online edition of the journal Genome Research, highlight the serious risks associated with vitamin D deficiency, especially for people who may be genetically predisposed to be sensitive to vitamin D deficiency, the study authors explained in a news release from Cold Spring Harbor Laboratory.

"Considerations of vitamin D supplementation as a preventative measure for these diseases are strongly warranted," Ramagopalan stated in the news release.

People should consume between 200 and 600 international units of vitamin D daily, according to a U.S. Institute of Medicine guideline, and the American Academy of Pediatrics recommends 400 international units daily. The U.S. guideline is currently under review, and many experts have called for an increase in the recommended intake levels.

Exposure to sunlight triggers the body to naturally produce vitamin D, although it can be hard to get enough in some regions during certain parts of the year. Vitamin D is also found in certain foods, such as fish, cheese, egg yolks and fortified milk and breakfast cereals.

More information

The Harvard School of Public Health has more about vitamin D and health.