Scientific studies link coffee taste and mood to genetics and gut bacteria

Recent scientific studies have revealed new insights into how coffee affects the human body, focusing on taste perception and mental health through the gut-brain axis.

Researchers at the Leibniz Institute of Food Systems Biology at the Technical University of Munich investigated why coffee bitterness varies between individuals. The study, published in Food Chemistry, identified that the compound mozambioside, which forms during roasting, is significantly more bitter than caffeine. Genetic analysis showed that variations in the TAS2R43 gene, which encodes a bitter taste receptor, influence how people perceive these compounds. Approximately 20% of Europeans possess a variant that eliminates this specific receptor, affecting their ability to taste certain bitter notes.

Separately, research conducted by APC Microbiome Ireland at University College Cork suggests that coffee may influence mood via gut bacteria. Published in Nature Communications, the study found that both caffeinated and decaffeinated coffee were associated with reduced stress, lower depression symptoms, and decreased impulsivity. These effects appear linked to changes in the gut microbiome, specifically increases in species such as Eggerthella and Cryptobacterium. While caffeinated coffee was linked to improved attention and reduced anxiety, decaffeinated coffee was associated with better learning and memory, suggesting that polyphenols play a key role in these benefits.