Urinary Concentrations of Polycyclic Aromatic Hydrocarbon Metabolites in Maté Drinkers in Rio Grande do Sul, Brazil

Background: Consumption of mate, an infusion of the herb Ilex paraguariensis (yerba mate), is associated with increased risk of esophageal squamous cell carcinoma (ESCC), but the carcinogenic mechanism is unclear. Commercial brands of yerba mate contain high levels of carcinogenic polycyclic aromatic hydrocarbons (PAHs), which are acquired during the traditional drying process. The purpose of this study was to characterize exposure to PAHs in mate drinkers over a wide range of mate consumption. Methods: We recruited 244 adults who answered a questionnaire and collected a fasting spot urine specimen. We quantified urinary concentrations of seven PAH metabolites, and assessed associations between self-reported recent mate consumption and urinary PAH metabolites by multivariate regression. Results: Recent mate consumption showed a significant dose-response association with 6 of 7 PAH metabolites in unadjusted models (p-for-trend <0.05). After adjustment for creatinine and potential confounders, concentrations of 2-naphthol, 1-hydroxyphenanthrene, and the sum of 2- and 3-hydroxyphenanthrene remained significantly associated with recent mate intake. The sum of the urinary concentrations of the phenanthrene metabolites was similar or higher among mate drinkers who did not smoke than among smokers who did not drink mate. Conclusions: Urinary concentrations of PAH metabolites were significantly associated with self-reported amount of recent mate intake, and drinking mate increased urinary concentrations of some PAH metabolites as much as smoking cigarettes. Impact: Drinking mate is a source of exposure to potentially carcinogenic PAHs, consistent with the hypothesis that the PAH content of mate may contribute to the increased risk of ESCC in mate drinkers.