Abstract
Caffeine, a common food component, is not banned or restricted in Japan. The ready availability of caffeine-containing products,
such as coffee, often leads to excessive consumption that can be associated with caffeine intoxication, as described in numerous
reports. We measured the caffeine content of coffee, a major contributor to caffeine intake, with a particular focus on single-serve
take-out products sold at convenience stores, coffee shops, and fast-food chains nationwide. As the results, the caffeine content
(0.72 ± 0.03 to 1.01 ± 0.04 mg/mL) was higher than the reference value (0.60 mg/mL) presented in the Standard Tables of Food
Composition in Japan, and the values varied markedly among the products. Additionally, there was considerable variability in the
caffeine concentration even among samples of the same product, with values ranging from 0.56 to 0.83 (mean, 0.74 ± 0.09) mg/mL
(n=8).
