The fluoride content of select brewed and microwave-brewed black teas in the United States

Fluoride (F) intake is recognized to be important for dental health. Tea leaves are known F accumulators and brewed tea as well as the water used for brewing may contribute significantly to individual intake. The USDA's Nutrient Data Laboratory determined the F content of brewed and microwaved teas using geographically matched tap water samples. Two brands of top-selling regular and one of decaffeinated teabags were purchased in 36 locations and brewed either by steeping in boiled water or with microwave heating followed by steeping. The mean F content for caffeinated regular brewed tea was 373 ± 49 μg/100 g (n = 63) and for decaffeinated tea was 270 ± 46 μg/100 g (n = 34). The overall mean for F in microwaved regular tea was lower than regular brew (364 ± 40 μg/100 g vs. 322 ± 30 μg/100 g (n = 36)). In all cases, prepared tea using water from the Midwest had the highest F-values. The mean F content of the brewed teas was 3-4 times higher than the national mean of the tap water, analyzed separately (71 ± 33 μg/100 g). These data are the first nationally representative F-values for brewed teas, and will provide valuable information to the dental and medical research communities in assessment of fluoride intake and impact on dental health.