Phytoestrogens are chemicals produced by plants that act like estrogens. These chemicals mimic and supplement the action of the bodies own hormones.
Lignans are one of the two major classes of phytoestrogens, they are naturally found in grains, berries and vegetables. Research has shown that lignans affect the estrogen signaling system. Estrogens play an important role in the development and progression of breast cancer.
Since the research shows that lignans affect the estrogen signaling system, they may therefore have a potential to affect breast cancer risk.
The lignan antioxidants can be found in flax seeds, pumpkin seeds, sesame seeds, rye, soybeans, broccoli, beans, and some berries.
This research will hopefully contribute to the development of further studies on the effects of phytoestrogens on cancer.
Nutrition expert, Professor David Jacobs, from the School of Public Health at the University of Minnesota, will present information at the Dietitians Association of Australia National Conference that indicate women who eat ten servings of whole grain foods per week live longer with less disease. Whole grain foods -- wheat, rice, corn, barley, oats, and rye -- contain the entire seed grain, including the bran and germ. Refinement of the grain strips the nutritious outer layer of the grain. 
