Research from the Washington University School of Medicine in St. Louis, Missouri, has shown that girls aged 9 to 15 years who regularly ate peanut butter or nuts were 39% less likely to develop benign breast disease by age 30 years. Although noncancerous, benign breast disease increases the risk of breast cancer developing in later life.
The findings could offer new insights into reducing breast cancer risk, according to the study's coleader Graham Colditz, MD, DrPH, associate director of prevention and control at Washington University's Siteman Cancer Center.
The research was based on the health histories of 9039 girls enrolled in The Growing Up Today Study from 1996 to 2001. From 2005 through 2010, the participants reported on whether they had been diagnosed with benign breast disease that had been confirmed by breast biopsy. Girls who ate peanut butter or nuts 2 times per week were found to be 39% less likely to develop benign breast disease than those who never ate them. Researchers also found that beans, lentils, soybeans, and corn may also help to prevent the condition but that the consumption of these foods was much lower among the girls, and therefore the evidence was weaker.
Although previous studies have linked peanut butter, nut, and vegetable fat consumption to a lower risk of benign breast disease, this study was the first to use reports made by girls during their adolescence rather than by asking adults to recall their high school diets years later.