Caffeine content of energy drinks marketed in Brazil.

Energy drinks represent a multibillionaire industry that has been growing continuously worldwide. These drinks are especially consumed by young people, athletes, and military personnel due to their claimed "boost" effects. However, there have been concerns about their consumption since incompatibilities regarding the accuracy of the declared caffeine content of these drinks have been reported. Therefore, in this study, we have developed a fast and simple method to quantify caffeine in energy drinks. Sample preparation consisted of a dilute-and-shoot process, and analyses were performed by gas chromatography with nitrogen-phosphorus detector (GC-NPD). The method was applied to quantify caffeine in 37 energy drinks marketed in Brazil. Compared with the labeled caffeine content, 84% of the tested drinks presented caffeine levels in accordance with the specifications. The determined caffeine concentrations ranged from 10 to 67 mg/100 ml, with an average value of 31 mg/100 ml. According to the recommended serving size, no drinks exceeded the safe caffeine daily intake for the general population (400 mg). These findings are more favorable than the results of similar studies. Nevertheless, to avoid caffeine intoxication, energy drink consumers should be aware of three aspects. First, they need to avoid consuming multiple serving doses in short periods of time. Additionally, some energy drinks are labeled as "nutritional supplements," so they may present much more caffeine than similar products commonly regulated as beverages. Finally, despite the growing interest in energy drinks, their consumption by children and early adolescents is being discouraged by the health authorities.