Dietary phytoestrogen intake—lignans and isoflavones—and breast cancer risk (Canada) Michelle Cotterchio Æ Beatrice A. Boucher Æ Nancy Kreiger Æ Catherine A. Mills Æ Lilian U. Thompson
Abstract Objective To evaluate whether phytoestrogen intake is associated with reduced breast cancer risk, using a novel phytoestrogen database. Methods Population-based breast cancer cases aged 25–74 years (diagnosed 2002–2003) were identified using Ontario Cancer Registry (n = 3,063) and controls (n = 3,430) were an age-stratified random sample of women identified through random digit dialing. An epidemiologic and Block food frequency questionnaire—expanded to include phytoestrogen-containing foods—was mailed to all subjects. The recently published Ontario phytoestrogen database was applied to FFQ responses to estimate intake. Multivariate logistic regression provided odds ratio (OR) estimates, while controlling for confounders. Results Among all women, lignan intake was associated with a reduced breast cancer risk (Q5 vs. Q1 MVOR: 0.81, 95% CI: 0.65, 0.99); however, following stratification by BMI, this reduction in risk was statistically significant only among overweight (BMI[25) women. Total phytoestrogen intake was also associated with a risk reduction among overweight women only. Among pre-menopausal women. total phytoestrogen intake was associated with a significant reduction in breast cancer risk among overweight women only (Q5 vs. Q1 MVOR: 0.51, 95% CI: 0.30, 0.87). Among post-menopausal women, no statistically significant association was observed between breast cancer risk and isoflavones or lignans.Conclusion Lignan intake may be associated with reduced breast cancer risk among pre-menopausal women, and our data suggest BMI modifies this association. NOTE Lignans are phytoestrogens with estrogenic or anti-estrogenic activity. Lignans may also have antioxidant activity. Plant lignan compounds are converted in the intestine to form of lignans (enterolignans) the human body can assimilate. Plant lignans come from sources such as flax seed (highest source) whole grain cereals, rye, legumes, seeds and nuts, berries, vegetables and fruits.
Isoflavones are a class of phytoestrogens—plant-derived compounds with estrogenic activity. Soybeans and soy products are the richest sources of isoflavones in the human diet.
Source:Cancer Causes Control (2008) 19:259–272 DOI 10.1007/s10552-007-9089-2 LINK TO SOURCE
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