Quantitative probabilistic assessment of caffeine intake from tea in Chinese adult consumers based on nationwide caffeine content determination and tea consumption survey.

Caffeine has known effects on the central nervous and cardiovascular systems. An intake up to 400 mg/day does not give rise to health concerns. Tea, a major source of caffeine, is highly consumed in China. However, the potential health risk of caffeine from tea has not been well evaluated. The present study assessed caffeine intake levels from tea for Chinese adult consumers. We collected 1,398 samples of green, black, dark, jasmine, oolong, white, and yellow tea from 17 provinces. The caffeine content was determined by HPLC. The average contents were 27 (oolong tea) – 43 (yellow tea) mg/g. The leaching rate of caffeine into the water was about 100%. Tea consumption data were from the National Beverage Consumption Survey 2013–2014. Monte Carlo simulations were applied to estimate the distribution of caffeine intake. The average caffeine intake from tea was 180 mg/day of all consumers. Green, dark, and black tea were the primary sources. Males (197 mg/day) consumed more caffeine than females (136 mg/day) on average, but females older than 71 years had the highest intake level (259 mg/day) among all subgroups. Over 90% of Chinese adult tea drinkers have caffeine intake under 400 mg/day. [Display omitted] • Caffeine intake up to 400 mg/day is safe for healthy adults. • The average caffeine contents in tea were 27 (oolong tea) – 43 (yellow tea) mg/g. • First national risk assessment on caffeine intake from tea for Chinese adults. • Caffeine contents in tea and consumption data was of national representation. • About 10% of Chinese adult tea drinkers consumed more than 400 mg/day of caffeine. [ABSTRACT FROM AUTHOR]