Vitamin D may decrease risk of colorectal cancer

A new study from Japan suggests that high blood levels of vitamin D may lower the colorectal cancer risk by 36%.

In this observational study, vitamin D blood levels and daily calcium intakes were analyzed in 737 people with colorectal cancer and 703 healthy, cancer-free individuals (1). The study results showed that participants with the highest average levels of 25(OH)D (32 ng/mL) had a 36% lower risk of colorectal cancer than people with the lowest average levels (16 ng/mL). High calcium intakes (590 mg/day) were also associated with a 37% lower risk of cancer than people with the lowest average intakes (542 mg/day).

The researchers concluded that these results would underline the importance of maintaining an optimal vitamin D status as a preventitive measure against colorectal cancer, at least in its early stages. Numerous studies have already suggested associations between vitamin D and lower risks of certain cancers. In 2011, scientists conducted a meta-analysis of nine observational studies and concluded that for every 10 nano-grams per milliliter-increase in levels of vitamin D (25-hydroxyvitamin D), the associated risk of colorectal cancer decreased by 15% (2). No association was observed between vitamin D levels and the risk of breast or prostate cancer.

1. Yamaji T. et al. Association Between Plasma 25-Hydroxyvitamin D and Colorectal Adenoma According to Dietary Calcium Intake and Vitamin D Receptor Polymorphism. American Journal of Epidemiology. Published online January 2012.
2. Gandini S. et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. Int. J. Cancer. 2011; 128(6):1414–1424.