A recent study from the Dana-Farber Cancer institute, the Harvard T.H. Chan School of Public Health, and other institutions has shown there may be a link between vitamin D consumption and the development of young-onset colorectal cancer and precancerous polyps. According to Richard Saltus of The Harvard Gazette, the study, which was published in the journal Gastroenterology, these findings could lead to future recommendations for increased vitamin D intake.
While cases of colorectal cancer have been declining, the percentage of new cases found in younger adults (under age 50) has been on the rise. Senior co-authors Kimmie Ng of Dana-Farber and Edward Giovannucci of the TH. Chan School noted in the study that the intake of vitamin D through foods such as fish, mushrooms, eggs, and milk has also seen a decline over the past several decades.
“Vitamin D has known activity against colorectal cancer in laboratory studies. Because vitamin D deficiency has been steadily increasing over the past few years, we wondered whether this could be contributing to the rising rates of colorectal cancer in young individuals,” Ng said. “We found that total vitamin D intake of 300 IU per day or more — roughly equivalent to three 8-oz. glasses of milk — was associated with an approximately 50 percent lower risk of developing young-onset colorectal cancer.”
Researchers examined the vitamin D intake, both dietary and supplementary, of participants in the Nurses’ Health Study (NHS) II, which included 94,205 women between the ages of 25 and 42, with a focus on those who developed young onset colorectal cancer. 111 women were identified to have been diagnosed with young onset colorectal cancer during the study. Information gathered during the study, such as height, weight, and diet were all used to help form conclusions. These participants also received a questionnaire asking if they had received a colonoscopy or sigmoidoscopy where colorectal polyps were found. These polyps can act as indicators for potential future colorectal cancer.
Results also showed researchers that vitamin D intake associated with natural dairy products, such as milk and eggs, provided larger benefits than those received through dietary supplements. It is unknown exactly why supplements failed to provide as much benefit, and it is believed more work must be done on the subject to form a conclusion.
“Our results further support that vitamin D may be important in younger adults for health and possibly colorectal cancer prevention,” said Ng. “It is critical to understand the risk factors that are associated with young-onset colorectal cancer so that we can make informed recommendations about diet and lifestyle, as well as identify high risk individuals to target for earlier screening.”