In many countries, breast cancer is the most commonly diagnosed and treated form of cancer. A 2014 meta-analysis of 16 studies has shown that there is a statistically significant association between serum selenium status and risk of breast cancer. The lower the serum selenium concentration, the greater the risk of breast cancer [Babaknejad].
What do we know about selenium and breast cancer?
Breast cancer is a frustrating topic for the selenium researcher. There is not enough evidence to permit definitive statements about the effects of selenium supplementation on the prevention of breast cancer.
For example, the Nutritional Prevention of Cancer (NPC) study – a study that showed significant associations between selenium supplementation and reduced risk of colorectal, lung, prostate, and total cancer – did not enroll enough women for the effect of selenium supplementation on breast cancer to be studied [Clark].