Fluoride Content and pH in Yerba Mate Infusions: A Study of South American Varieties

This study aimed to assess the fluoride content and pH in yerba mate infusions from commercial products from Argentina, Brazil, Paraguay, and Uruguay. A total of 67 products labeled as yerba mate were purchased in duplicate with different lot numbers. Each infusion was prepared using 10 g of yerba mate and 50 mL of deionized water at 85 °C, and 10 min was allowed for infusion. Fluoride levels and pH were measured using a calibrated ion-specific electrode and a pH glass electrode, respectively. A total of 21 samples were from Argentina, 20 from Brazil, 17 from Paraguay, and 9 from Uruguay. Heterogeneity in fluoride levels was observed across samples (0.001 to 5.9 mg/L). Notably, one product from Paraguay exhibited a significantly elevated fluoride concentration compared to others. Additionally, the infusions were found to be slightly acidic, with the pH ranging from 5.1 to 6.4. This study demonstrated that yerba mate infusions sold in the main producing countries in South America present wide variability in fluoride concentration, with values ranging from 0.001 to 5.946 mg/L, and most products presented safe fluoride levels. The substantial variability in fluoride and pH observed among commercially available yerba mate infusions highlights the need for regular monitoring and clearer labeling of fluoride content in such beverages.