Increased intake of fiber during adolescence and young adulthood is associated with decreased risk of breast cancer in adulthood.
Dietary Fiber Intake in Young Adults and Breast Cancer Risk
Authors: Farvid MS, Eliassen H, Cho E, et al.
Source: Pediatrics. 2016:137:1-11
Estrogen is one of the hormones responsible for breast development. A high-fiber diet has been suspected to limit the absorption of estrogen, thereby decreasing the risk of breast cancer. Fiber may also decrease risk by enhancing insulin sensitivity. However, no studies have yet supported these theories. One reason for this may be that subjects have not been followed long enough to see an effect.
Started in 1989, the Nurses' Health Study II (NHSII) is following more than 100,000 women to assess their health outcomes over time. Farvid et al identified more than 47,000 of these women for evaluation in this study. Participants were asked to provide details about their diet during high school. Surveys were sent out every few years. Food nutrition values were obtained from the U.S. Department of Agriculture, food manufacturers, and academic sources. Breast cancer risk factors, such as alcohol consumption, cigarette smoking, and body mass index (BMI), during adolescence and in adulthood were documented as well.
The group found that women with higher fiber intake during early adulthood and adolescence had significantly lower rates of breast cancer. The reduction was stronger for premenopausal disease; however, the reduction for postmenopausal cancer was also significant.
The incidence of breast cancer was not affected by consumption of red meat or animal fat. Alternate healthy eating habits did not affect the rate of breast cancer.
This large study determined that there is an association between dietary fiber intake in young adulthood and breast cancer in adulthood. A diet rich in fruits, vegetables, and whole grains has a long-term effect of decreasing breast cancer risk.