b4d1ced9_sity_of_Michigan_Health_System__Why
[Recommendation] Feast on fiber [Why] 
Many studies have shown that people who eat plenty of whole grains have a lower risk for breast cancer. Insoluble fiber from grains delays the onset of mammary (breast) cancer in animals.58 In an analysis of the data from many studies, people who eat relatively high amounts of whole grains were reported to be at low risk for breast cancer.59 In some studies, the protective effect of fiber against the risk of breast cancer has been stronger in young women than in older women.60 This finding might occur because fiber has been reported to lower estrogen levels in premenopausal women but not in postmenopausal women.61 , 62 Other researchers, however, report that fiber appears to equally reduce the risk of breast cancer in women of all ages.63 One leading researcher has suggested the active components in fiber may be phytate and isoflavones, substances that may provide protection even in the absence of a decrease in estrogen levels.64 If these substances do protect against breast cancer, they might be as helpful in older women as in younger women. Consuming a diet high in insoluble fiber is best achieved by switching from white rice to brown rice and from bakery goods made with white flour or mixed flours to 100% whole wheat bread, whole rye crackers, and whole grain pancake mixes. Refined white flour is generally listed on food packaging labels as “flour,”“enriched flour,”“unbleached flour,”“durum wheat,”“semolina,” or “white flour.” Breads containing only whole wheat are usually labeled “100% whole wheat.”
Breast Cancer Prevention (Holistic) | University of Michigan Health System