Lignans are phytoestrogens with antioxidant activity found in the cell walls of plants. Common dietary sources include flaxseed, soybeans, whole-grain cereals (especially rye), broccoli, pumpkin seeds, and certain berries.
A large prospective study published in the Journal of the National Cancer Institute (2007; 99[6]:475–486) evaluated dietary lignan intake in 58,049 postmenopausal French women. Lignan intake was assessed using a self-administered dietary history questionnaire. Importantly, the women were not using soy isoflavone supplements, allowing the analysis to focus on lignans from whole foods.
Women in the highest quartile of lignan intake had a 17% lower risk of developing breast cancer compared with those in the lowest quartile. The findings suggest that higher dietary lignan intake is linked with a reduced risk of breast cancer in postmenopausal women.
Research appearing in Cancer Causes and Control (2006; 17(10): 1253-61) looked at diet and breast cancer risk. The population-based, case-controlled study looked at 3,024 patients between the ages of 25 and 74 years and compared them to 3,420 matched controls. Participants were given a food frequency questionnaire. It was found that the incidence of breast cancer and diet during adolescence. Eating lignans and isoflavones (phytoestrogens) during the teen years reduces the chance of developing breast cancer later in life.
