Int J Food Sci Nutr. 2015 Feb;66(1)

This study systematically reviewed original breast cancer research published in English over the last decade in order to assess the role specific foods and nutrients may play in breast cancer risk. High alcohol intake was widely and clearly recognized as one of the factors most consistently associated with breast cancer risk. Some studies suggested that soy food intake decreased risk, while there was no clear association between breast cancer risk and dietary carbohydrates and fiber. There was limited evidence for a causal relationship between the consumption of fruits and vegetables and breast cancer risk, so no specific conclusions could be reached from the literature on that subject. Similarly, there were contradictory findings about the relationship between breast cancer and different types of dietary fat, so further studies on that relationship are necessary. The authors concluded that even though diet seems to be modestly associated with breast cancer risk, more studies are required to determine specifics.