The effects of CYP1A2 and ADORA2A genotypes association with acute caffeine intake on physiological effects and performance: A systematic review

Introduction: This systematic review aims to examine the effects of the CYP1A2 −163C>A and ADORA2A 1976T>C polymorphism on physiological effects and performance relative to caffeine consumption. Material and Methods: In this study, electronic databases including PubMed, Web of Science Core Collection, Korean Journal Database, Russian Science Citation Index, SciELO Citation Index, Scopus, ScienceDirect, ProQuest Dissertations & Thesis Global and EBSCO were searched. Results: The results highlight that individuals with the TT or CT/CC genotype can have differences in caffeine consumption, and C carriers may have increases in the maximum oxygen uptake (VO2max). The AA or AC/CC genotypes can have different caffeine consumption and VO2max. In four studies, TT or CT/CC either in AA or CC genotype had different physiological effects. Regardless of the amount of caffeine (3 mg/kg-5 mg/kg), Carriers of the C allele in the genotype ADORA2A gene have higher sports performance. Six studies revealed a significant correlation between the AA genotype and performance following caffeine intake. Conclusions: Genotype variations in ADORA2A and CYP1A2 may modulate the ergogenic effects of caffeine, but some physiological effects can occur for different genotypes.