Caffeine in teas: levels, transference to infusion and estimated intake

Caffeine is naturally present in several foods, being one of the most consumed dietary ingredients in the world; however, excessive intake may cause health concerns. This study evaluated caffeine levels in teas and their infusions, the transference rate during brewing, and estimated caffeine intake from tea infusion. Brands and batches of 4 types of teas were analyzed for caffeine content by high performance liquid chromatography with a diode array detector. Mate tea was the one that presented lowest levels (6.1 to 13.2 mg/g) while Camellia sinensis teas were from 14.3 to 34.8 mg/g. There were statistical differences between different types, brands and batches. Caffeine levels in infusions followed the same pattern of the leaves, with mate tea presenting lowest levels. Caffeine percentage of transference from leaves to infusion varied from 51.5 to 85.2%. Caffeine intake was estimated to be up to 191.4 mg/day. Tea may be considered an important source of caffeine intake for heavy tea drinkers.