Coffee is one of the world's most widely consumed beverages, and previous research has linked its consumption to a lower risk of conditions such as type 2 diabetes and cardiovascular disease. However, the biological mechanisms behind these benefits remain unclear. A new Finnish study links habitual coffee consumption to healthier body composition and metabolic markers, while revealing distinct associations with sex hormones in men and women.
The study, conducted at the University of Oulu, analysed data from 2,264 participants aged 46 in the Northern Finland Birth Cohort 1966. Researchers examined how habitual coffee consumption was associated with circulating metabolites, cardiometabolic risk markers and sex hormones.
Despite having a similar body mass index (BMI), individuals with higher coffee consumption had lower total and visceral fat and greater skeletal muscle mass than those who consumed less coffee.
In both men and women, higher coffee consumption was correlated with lower circulating levels of branched-chain amino acids, biomarkers that have previously been linked to insulin resistance and an increased risk of type 2 diabetes when chronically elevated.
The strongest sex-specific associations were observed in men. Higher coffee consumption was linked to a more favourable glucose–insulin profile, higher concentrations of total and bioavailable testosterone, and increased levels of sex hormone-binding globulin (SHBG). At the same time, free testosterone and the free androgen index were modestly lower. In women, hormonal associations were more limited and were primarily characterised by higher SHBG and lower measures of free androgens.
"Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones. What stood out in our findings was a distinct hormonal signature that didn't disappear even after we took into account BMI and lifestyle factors, with several of these associations differing between men and women," says Luca Verroest, lead author of the study and Doctoral Researcher at the University of Oulu.
The results suggest that hormonal pathways may partly explain the relationship between coffee consumption and metabolic health. However, as this was an observational study, the findings demonstrate associations rather than cause-and-effect relationships.
The study is particularly relevant in Finland, one of the world's highest coffee-consuming countries, where annual consumption averages around 11.8 kilograms per person.
The researchers say the findings provide a foundation for future studies aimed at determining whether coffee itself drives these biological changes and identifying the compounds responsible. These questions are currently being investigated in animal models, with the long-term goal of progressing to human intervention studies. Further research will be needed before the findings could inform dietary recommendations.