Can Vitamin D Protect Against Autoimmune Disease, Cancer?
Vitamin D has been linked to a variety of autoimmune diseases and cancer, and now scientists have uncovered genetic evidence to support their beliefs. Investigators at Oxford University present their findings in Genome Research.
Vitamin D research on autoimmune disease and new evidence
Scores of previous studies have looked into links between vitamin D and a variety of autoimmune diseases and other conditions, including cancer, depression, cognitive problems, and obesity, among others. A recent study from Boston University School of Public Health, for example, reported on the possible contribution of vitamin D deficiency to rheumatoid arthritis.
A Tufts Medical Center report noted that “vitamin D has been shown to modulate the immune system, and its deficiency has been linked to the development of several autoimmune disorders.” There is also some evidence that keeping vitamin D levels up in the elderly can improve cognitive flexibility.
Genetic researcher Sreeram Ramagopalan and colleagues evaluated how vitamin D receptors bind to gene areas that have been identified with specific diseases. They discovered increased binding for various autoimmune diseases and several types of cancer, including colorectal and chronic lymphocytic leukemia. Overall, the researchers found 2,776 binding sites for the vitamin D receptor and showed that the nutrient had a significant impact on the activity of 229 genes, including those associated with multiple sclerosis, Crohn’s disease, and type 1 diabetes.
Ramagopalan told WebMD that “Genes involved in autoimmune disease and cancer were regulated by vitamin D,” and that the next step is to uncover how the relationship between vitamin D and these genes can result in disease.
The Need for Vitamin D
Many experts, including Ramagopalan, the Vitamin D Council, and others, point out that the current recommended daily intake for vitamin D is much too low (200 IU [International Units] for people up to age 50; 400 IU for people 51 to 70; 500 IU for people older than 70). Studies also indicate that at least 50 percent of adults and children in the United States are vitamin D deficient.
A simple blood test to identify 25-hydroxyvitamin D can be done to determine a person’s vitamin D level. Levels lower than 20 nanograms per milliliter (ng/mL) are usually considered deficient. Edward Giovannucci, MD, a Harvard School of Public Health nutrition researcher, believes levels between 30 and 40 ng/mL can reduce the risk of autoimmune diseases and some cancers. The Vitamin D Council states that everyone should maintain a level of 50 to 80 ng/mL.
Ramagopalan says 2,000 IU daily may be needed to prevent disease, while the Vitamin D Council recommends 5,000 IU. Getting a sufficient amount of the vitamin can be accomplished by a few approaches. Vitamin D is called the sunshine vitamin for good reason: exposure to sunlight prompts the body to make the vitamin. Food sources of the nutrient include fortified milk, oily fish, fortified cereals, and eggs. Supplements are also an option.
Can vitamin D help protect against autoimmune disease and cancer? It seems clear that vitamin D has a major role in human health, and this latest study is a major step toward better understanding the link between this nutrient and the prevention and potential treatment of many serious diseases.
Oxford University, news release August 24, 2010
Vitamin D Council