Vitamin D is an essential nutrient that is good for the health, and scientists continue to explore its other health benefits. In fact, a new study found that vitamin D reduces the risk of cancers. The large Japanese cohort study, published in the BMJ, aimed to determine whether vitamin D was associated with the risk of total cancer and certain cancers.
The researchers conducted the study using data of 33,736 participants from the Japan Public Health Center-based Prospective (JPHC) Study. The participants were aged between 40 and 69 years. At the beginning of the study, they provided detailed information on their medical history, diet, and lifestyle. Their blood samples were also taken to measure vitamin D levels.
Then, the researchers divided the participants into four groups, depending on their levels of vitamin D. After that, they observed the participants for an average of 16 years, in which they recorded more than 3,300 new cases of cancer. The study also included 4,044 randomly selected sub-cohort participants.
After cancer risk factors, such as age, weight, physical activity levels, smoking, alcohol consumption, and diet, were considered, the researchers found that participants with a higher level of vitamin D had a 20 to 25 percent lower risk for all cancers. For liver cancer, they showed a 30 to 55 percent lower risk of cancer, and the association was more evident in men than in women. In addition, they found that vitamin D levels lower the risk for pre-menopausal breast cancer, but not for prostate and lung cancer.
Furthermore, they observed a ceiling effect for total cancer risk, which suggested that no further benefit would be provided beyond a certain vitamin D blood concentration. However, they failed to determine the optimal vitamin D concentration that reduced the risk of cancer.
“We observed that a higher circulating concentration of vitamin D was associated with a lower risk of subsequent cancer in a large Japanese population. Our findings support the hypothesis that vitamin D may confer protection against the risk of cancer,” said Sanjeev Budhathoki, first author of the study.