According to new research by Dana-Farber Cancer Institute investigators, vitamin D can exert a protective effect against colorectal cancer by enhancing the immune system’s capacity to detect cancer cells.
The study, published in the Gut journal, provides the first experimental evidence of a link between vitamin D and anti-tumoral immune responses in a large human population.
“People with high levels of vitamin D in their bloodstream have a lower overall risk of developing colorectal cancer,” study author, Shuji Ogino, MD, PhD, of Dana-Farber, Harvard School of Public Health, and Brigham and Women’s Hospital, said in a news release. “Laboratory research suggests that vitamin D boosts immune system function by activating T cells that recognize and attack cancer cells. In this study, we wanted to determine if these two phenomena are related: Does vitamin D’s role in the immune system account for the lower rates of colorectal cancer in people with high circulating levels of the vitamin?”
Dr. Ogino and his team hypothesized that people with increased levels of vitamin D would have a decreased tendency to develop colorectal tumors that are surrounded by immune cells in their microenvironment. And those that eventually develop these tumors would have an increased resistance to the patient’s immune response.
The team analyzed data from a total of 170,000 participants in the Nurses’ Health Study and Health Professionals Follow-up Study, two long-term health-tracking research projects. They then proceeded to compare blood samples of colorectal cancer patients and healthy subjects, taken in the early 1990’s, before any of them had developed the malignancy. The samples were tested for 25-hydroxyvitamin D, a vitamin D component produced by the liver.
The results demonstrated that patients who had high levels of 25(OH)D had a decreased risk of developing colorectal cancer enriched with immune cells.
“This is the first study to show evidence of the effect of vitamin D on anti-cancer immune function in actual patients, and vindicates basic laboratory discoveries that vitamin D can interact with the immune system to raise the body’s defenses against cancer,” Dr. Ogino added. “In the future, we may be able to predict how increasing an individual’s vitamin D intake and immune function can reduce his or her risk of colorectal cancer.”