A key study published in the European Journal of Cancer Prevention reported that a high blood level of lignans was associated with a 58% reduction of breast cancer risk. A study published in the Journal of the National Cancer Institute reported a 17% reduction in breast cancer for women with the highest lignan intake. In another study published in the American Journal of Clinical Nutrition, women consuming about 1 ounce of flaxseed daily had lower levels of toxic estrogen metabolites that harm breast tissues.