Post-diagnosis isoflavone and lignan intake in newly diagnosed breast cancer patients: cross-sectional survey shows considerable intake from previously unassessed high lignan foods

2 Background: Isoflavones and lignans (phytoestrogens) are dietary components with potential 3 anti-carcinogenic effects. Although the intake of isoflavones and lignans may affect breast 4 cancer treatment and prognosis – and associations may differ by menopausal status post5 diagnosis intake data are limited. 6 Objective: We aimed to describe post-diagnosis isoflavone and lignan intake in newly diagnosed 7 breast cancer patients, examine differences by menopausal status and phytoestrogen type, and 8 inform the assessment of diet and survival in future prognostic studies. 9 Methods: Our cross-sectional study included 278 women aged 25-74 years, diagnosed with 10 pathologically confirmed breast cancer in April-May 2010 and identified using the Ontario 11 Cancer Registry. Intake in previous 2 months was assessed using questionnaires listing 17 soy 12 and 3 high lignan foods (flaxseed, flaxseed bread, sesame seeds), completed 71 days after breast 13 cancer diagnosis, on average. Food consumption by menopausal status was examined. Geometric 14 mean and median phytoestrogen intakes were estimated among all patients and in consumers 15 only; differences by menopausal status and phytoestrogen type were assessed. 16 Results: Among all patients, foods were similarly consumed by menopausal status and 17 isoflavone intakes were low (median 56 μg/day). Consumers (n=219) had higher intakes (median 18 isoflavones 1808 μg/day); 7% of isoflavone and 21% of lignan consumers had intakes ≥10 19 mg/day. Intakes were higher in premenopausal than postmenopausal consumers, particularly for 20 lignans, but were not significantly different (median lignans 4375 vs 1863 μg/day; p=0.07). 21 Lignans were significantly higher than isoflavones among most consumers (postmenopausal 22 means 746 vs 100 μg/day; p<0.0001). 23 Nutrition. DOI: 10.3945/cdn.117.002063 on January 24, 2018 First published online on December 19, 2017 in Current Developments in cdn.nutrition.org Downloaded from