‘Mate’ Intake, Hormone-Based Risk Factors and Breast Cancer: a Case-Control Study.

Previous reports on the inverse association between ‘mate’ intake (infusion of Ilex Paraguariensis herb) and breast cancer (BC) risk led us to consider two main roles for the infusion: as a substantial antioxidant contributor and as a hormone regulator, particularly through anti-aromatase capacities. Since menstrual-reproductive risk factors for BC reflect women’s estrogenic exposure during the reproductive lifespan, and considering that ‘mate’ intake exerts putative stronger protection among high antioxidant contributors, we attempted to analyze interactions among the infusion, hormon-linked reproductive factors and BC risk, which have hitherto remained unexplored. We analyzed a database of 572 BC incident cases and 889 controls. Women were interviewed with a specific questionnaire featuring socio-demographic, lifestyle and reproductive variables (age at menarche, 1st live birth and menopause; number of live births; breastfeeding months), and a food frequency questionnaire, focusing on ‘mate’ intake (consumer status, daily intake, age at start, age at quit, duration of habit). Odds ratios (OR) and their 95% confidence Intervals were calculated through unconditional logistic regression, adjusting for relevant potential confounders. ‘Mate’ intake showed strong inverse associations with some high-risk hormone-related factors: early menarche, nulliparity, low breastfeeding, long reproductive years and high number of ovulatory cycles. Moreover, all subsets of high dietary energy demonstrated even stronger associations. In conclusion, regarding exposure to known hormone risk factors, we found strong inverse associations between high ‘mate’ intake and BC, which were greater among those consuming higher calorific diets. Our analyses support possible combined antioxidant and antiestrogenic effects for ‘mate’ infusions.