Alcohol mixed with energy drink (AMED): Meta-analyseson the effects on alcohol consumption and subjective intoxication

Purpose: Over the past decade, there has been much controversy regarding the possible effects of mixing alcohol with energy drink (AMED) on alcohol consumption and subjective intoxication (i.e., the masking effect, in which drinkers assume their blood alcohol concentration (BAC) is lower than it actually is). The current meta-analyses summarize research on both alcohol consumption and subjective intoxication. Methods: A literature search was conducted to identify all relevant studies conducted over the past 10 years. Separate meta analyses were conducted to determine possible effects on alcohol consumption and subjective intoxication. Studies presenting within-subject comparisons were included, comparing alcohol consumption of AMED consumers on AMED occasions with Alcohol Only (AO) occasions. Results: Concerning alcohol consumption, the literature search identified fourteen studies, of which nine studies were included in the meta-analysis. These studies reported on within-subject comparisons among N = 3729 AMED consumers regarding their typical amount of alcohol consumption on AMED and AO occasions. The analysis revealed no significant difference in overall alcohol consumption on a typical drinking episode between AMED and AO occasions (p > 0.05). Concerning masking, seventeen studies were identified. Ten of them could be included in the meta-analysis. Caffeine dosages ranged from 2.0 to 5.5 mg/kg (i.e., 46 - 383 mg), and alcohol levels ranged from 0.29-1.068 g/kg, corresponding to a BAC ranging from 0.03 to 0.12%. For higher caffeine dosages, no significant masking effect was found (p > 0.05). For lower caffeine dose studies, also no significant masking effect was found (p > 0.05). Conclusion: Mixing alcohol with energy drink has no significant effect on overall alcohol consumption, nor does it affect the judgment of subjective intoxication.