A group from Spain (MCC – Spain) have found a possible link between breast cancer risk and vitamin D (25-OH-vitamin D) levels in the blood. Vitamin D has been shown to protect against colorectal cancer but the connection between breast cancer risk and vitamin D levels is less clear. The Spanish group presented their results at the recent San Antonio Breast Cancer Symposium and overall, in this study breast cancer risk decreased as the levels of vitamin D increased. This effect was seen in both pre and post-menopausal women. The most beneficial effect was seen in reducing the risk of triple negative (hormone receptor negative and Her-2 negative) breast cancer.
It is estimated that as many as 50% of people in the world are vitamin D deficient. It therefore seems sensible to make sure that your vitamin D levels are within the normal range for the whole year. There is absolutely no advantage increasing vitamin D to ‘super-normal’ levels and this may even be detrimental to general health and breast cancer risk.