CAMBRIDGE, England—Phytoestrogen intake was not associated with breast cancer among women or colorectal cancer among men in a recent University of Cambridge study (Am J Clin Nutr (December 9, 2009). doi:10.3945/ajcn.2009.28282).
Dietary phytoestrogen, plant substances that have weak estrogen-like activity, intakes were evaluated in about 25,000 cancer-free, 40- to 79-years-old British patients who participated in the European Prospective Investigation into Cancer and Nutrition - Norfolk (EPIC-Norfolk) between 1993 and 1997. Subjects filled out a diet diary for a week and provided information about age, height, weight, smoking, aspirin use, menopausal status and family history of cancer. More than 10,500 food items were analyzed for the phytoestrogens: isoflavones (genistein, daidzein, glycitein, biochanin A and formononetin), lignans (secoisolariciresinol and matairesinol), and enterolignans from gut microbial metabolism in animal food sources (equol and enterolactone).
Within 12 months of study, 244 breast cancers, 221 colorectal cancers and 204 prostate cancers were reported. The diets and other relevant information from those who developed cancer were compared to information from participants who did not develop cancer.
Among women, colorectal cancer risk was inversely associated with enterolactone (OR: 0.33; 95 percent CI: 0.14, 0.74) and total enterolignans (OR: 0.32; 95 percent CI: 0.13, 0.79), with a positive trend detected for secoisolariciresinol (OR: 1.60; 95 percent CI: 0.96, 2.69). In men, a positive trend between enterolignan intake and prostate cancer risk (OR: 1.27; 95 percent CI: 0.97, 1.66) was reduced after adjustment for dairy intake (OR: 1.19; 95 percent CI: 0.77, 1.82).
Researchers concluded they found no association between phytoestrogen intake and breast cancer in women or between phytoestrogen intake and colorectal cancer in men.