Scientists Uncover Hidden Link Between Coffee, Gut and Brain Health - Video

Coffee may influence the gut microbiome and brain function beyond its effects on alertness, according to a study published in Nature Communications.

Researchers from APC Microbiome Ireland at University College Cork examined 62 adults, including 31 regular coffee drinkers and 31 people non-drinkers. Regular drinkers consumed three to five cups daily.

Participants who drank coffee stopped for two weeks before coffee was reintroduced as either caffeinated or decaffeinated coffee. Researchers collected stool and urine samples and assessed mood, stress and cognition.

Stopping coffee was associated with changes in metabolites, suggesting that coffee consumption can influence metabolic activity involving gut microbes in the body.

After coffee was reintroduced, both caffeinated and decaffeinated groups reported lower stress, depression and impulsivity scores. Researchers also identified differences in several bacteria, including Eggertella and Cryptobacterium, among coffee drinkers.

Interestingly, caffeinated and decaffeinated coffee showed different associations. Improved learning and memory were observed among participants consuming decaffeinated coffee, suggesting that compounds other than caffeine may contribute to cognitive effects.

Caffeinated coffee was associated with lower anxiety and improved vigilance and attention. Researchers suggested that caffeine, polyphenols and other coffee compounds may directly influence the gut-brain axis through changes in gut microbes and microbial metabolites.

The gut-brain axis is a communication system involving the nervous system, immune signals, hormones and chemicals produced by microorganisms. Changes in these pathways could influence mood, stress and cognition.

However, the findings should be interpreted cautiously. The study included a small number of participants, and the associations do not prove that coffee directly causes changes in the microbiome, mood or cognition. The study was also sponsored by the Institute for Scientific Information on Coffee.

Larger studies are needed to determine whether coffee components or microbiome changes are responsible for the observed effects.

REFERENCE:

1.Ayokunnumi Ogunsanya, et al.; USP15 regulates mitotic fidelity, metastatic potential, and chemotherapeutic response in ovarian cancer cells. Molecular Therapy Oncology, 2026; 34 (3): 201329 DOI: 10.1016/j.omton.2026.201329

2.Serena Boscaini, et al.; Habitual coffee intake shapes the gut microbiome and modifies host physiology and cognition. Nature Communications, 2026; 17 (1) DOI: 10.1038/s41467-026-71264-8