How much consumed caffeine is actually absorbed? Bioaccessibility and bioavailability in energy drinks, infusions and soft drinks

Abstract

Caffeinated beverages have become a common dietary habit especially among adolescents, young adults and athletes due to their cognitive and physical performance-enhancing effects. This study evaluates the bioaccessibility (release during digestion) and bioavailability (intestinal absorption) of caffeine in coffee, teas, soft and energy drinks by applying an in vitro gastrointestinal digestion, with the aim of quantifying the real exposure to caffeine. Bioaccessibility values of 87-112 % for infused beverages, 83-103 % for soft drinks and 94-104 % for energy drinks were obtained, while bioavailability ranged from 62 to 76 %; 65-79 % and 52-76 %, respectively. Consuming a whole can of an energy drink results in a bioavailable caffeine content up to 115 mg. While these values remain within the recommended single-dose intake limit of 200 mg for adults, approaching recommended upper intake levels, particularly for children and adolescents.

Keywords: Bioaccessibility; Bioavailability; Caffeine; Energy drinks; In vitro gastrointestinal digestion; Soft drinks.