High Vitamin D levels can reduce cancer risk

Tokyo: People with higher levels of Vitamin D may be at a lower risk of developing all cancers, specifically liver cancer, a study involving over 30,000 participants has found. Vitamin D is made by the skin in response to sunlight. It helps to maintain calcium levels in the body to keep bones, teeth and muscles healthy. 

While the benefits of Vitamin D on bone diseases are well known, there was growing evidence that Vitamin D may benefit other chronic diseases, including some cancers. The researchers found that a higher level of Vitamin D was associated with a lower (around 20 per cent) relative risk of overall cancer in both men and women. Higher vitamin D levels were also associated with a lower (30-50 per cent) relative risk of liver cancer. The association was more evident in men than in women.

"Higher vitamin D concentration was associated with lower risk of total cancer. These findings support the hypothesis that vitamin D has protective effects against cancers at many sites," said Taiki Yamaji, from the National Cancer Centre in Tokyo. For the study, published in the journal The BMJ, the team analysed 33,736 male and female participants aged between 40 to 69 years and were then monitored for an average of 16 years.

No association was found for lung or prostate cancer. None of the cancers examined showed an increased risk associated with higher vitamin D levels. While the findings support the theory that Vitamin D may protect against the risk of cancer, there may be a ceiling effect, which may suggest that there are no additional benefits beyond a certain level of Vitamin D, Yamaji said. However, "further studies are needed to clarify the optimal concentrations [of Vitamin D] for cancer prevention", the researchers noted.