Researchers at the Dana-Farber Cancer Institute discovered that high levels of vitamin D in patients with colorectal cancer, prior to treatment, resulted in higher survival rates when compared to patients with lower vitamin D levels.
The study entitled “Plasma 25-hydroxyvitamin D and colorectal cancer risk according to tumour immunity status” was published in the journal Gut. This is the first time that an association is proven between vitamin D levels and the body’s immune response to cancer.
“People with high levels of vitamin D in their bloodstream have a lower overall risk of developing colorectal cancer,” senior study author, Dr. Shuji Ogino, 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?”
In order to determine if there was indeed a link between high levels of vitamin D and the likelihood of developing colorectal tumors, the team used data from two long-term health-tracking research projects – Nurses’ Health Study and Health Professionals Follow-up Study. From these, 942 patients were selected, 318 with colorectal cancer and 624 free of cancer. All patients had blood samples drawn before developing cancer. The samples were tested for 25-hydroxyvitamin D [25(OH)D], which is a substance produced in the liver from vitamin D.
The researchers discovered that patients with high levels of 25(OH)D in the bloodstream had indeed a lower-than-average risk of developing colorectal tumours, which are enriched with cells from the immune system. The team believes that this is the result of a boosting effect played by vitamin D on the immune cells that subsequently enhances the anti-tumoral function of the body’s immune system.
“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.”
These findings support the growing body of evidence that vitamin D, also known as the “sunshine vitamin” (vitamin D is produced by the body upon exposure to sunlight), plays an important role in cancer prevention.
