Vitamin D may influence the risk of certain diseases by affecting gene expression, according to a study published in the peer-reviewed journal Genome Research. Researchers found that vitamin D binds directly to genes associated with several common autoimmune diseases, including multiple sclerosis, type 1 diabetes, rheumatoid arthritis and colorectal cancer. They suggest vitamin D might impact disease risk by altering the activity of certain genes. The U.K.’s National Health Service (NHS) explained that at the cellular level, vitamin D binds to a protein called vitamin D receptor (VDR), and the resulting combination (called a vitamin D complex) can then bind to specific sites in the DNA called “vitamin D response elements.” This can affect the activity of nearby genes. In this laboratory study, researchers set out to identify genes that change their activity in response to vitamin D, and where in the DNA the vitamin D complex binds. Their aim was to investigate how vitamin D might affect processes at the cellular level. Researchers identified 2776 sites in the DNA that were related to VDR binding, and 229 genes that showed significant changes in their activity in response to vitamin D. They found that VDR binding sites were more common near genes that have been associated with several common autoimmune diseases. These were: multiple sclerosis (2.2 times more common); type I diabetes (2.9 times more common); Crohn’s disease (3.5 times more common); systemic lupus erythematosus (5.1 times more common); rheumatoid arthritis (2.8 times more common); chronic lymphocytic leukemia (8.3 times more common); and colorectal cancer (4 times more common).