The diversity in the ADORA2A and CYP1A2 genes may alter the connection between brain-related outcomes and caffeine, according to a systematic review of observational studies and randomized trials. The goal of Angeliki Kapellou et al. was to examine the link between outcomes pertaining to the human brain, caffeine use, and common genetic variants.

Using a predetermined search strategy, databases such as Embase and PubMed were explored for searching pertinent reports. The experimental and observational study reports on healthy people who underwent (i) Genetic testing for polymorphisms in the genes involved in the effects and metabolism of caffeine, and (ii) Measures of brain-linked effects (like cognitive function, sleeplessness, and anxiety) of caffeine use (either supplementation or habitual intake) were taken into consideration.

Out of the 22 incorporated records, 1 was a genome-wide association study, 6 were cross-sectional studies, and 15 were randomized controlled trials. Cognitive function (n = 9), anxiety (n = 7), and insomnia/sleep disturbance (n = 6) were the major endpoints ascertained. Variations in the ADORA2A gene were linked to sleep disruption and anxiety, whereas polymorphisms in the CYP1A2 gene were related to cognitive performance.

Variability in the ADORA2A and CYP1A2 genes may influence the link between brain-related consequences and caffeine. Future research is necessary to determine the precise polymorphisms involved in each brain outcome, which cognitive functions (simple vs. complex) are most influenced by caffeine, whether gender differences exist in the anxiety effects, and how habitual caffeine consumption may affect the acute caffeine effects.