Coffee remains one of the most widely consumed beverages in the world, and researchers have long studied whether it may help explain lower rates of conditions such as type 2 diabetes and cardiovascular disease seen in some populations. New findings from Finland now add a more detailed look at how regular coffee intake tracks with body composition, metabolic markers, and sex hormones in midlife adults. The research centers on a large birth cohort in Northern Finland, where coffee consumption is especially high by global standards.
Researchers tracked 2,264 adults and found measurable body-composition differences
The new study came from the University of Oulu and was published in the European Journal of Nutrition on July 16, 2026, according to the journal record and the university’s summary of the findings. Researchers analyzed cross-sectional data from 2,264 participants in the Northern Finland Birth Cohort 1966, all age 46 at the time of assessment. The team examined habitual coffee intake alongside circulating metabolites, cardiometabolic risk markers, and sex hormone levels.
The clearest body-composition findings were that participants with higher coffee consumption tended to have lower total body fat, lower visceral fat, and greater skeletal muscle mass, according to the University of Oulu and the published paper. Those differences appeared even though body mass index was similar across higher- and lower-intake groups. That distinction matters because BMI alone can miss meaningful differences in fat distribution and lean mass.
Researchers also reported lower circulating branched-chain amino acid concentrations in both men and women with higher coffee intake. The paper noted that persistently elevated branched-chain amino acids have previously been linked with insulin resistance and greater type 2 diabetes risk. The study’s authors said the results show associations, not proof that coffee directly produced those outcomes.
The study was based in Northern Finland, and its findings reflect that population
The data came specifically from the Northern Finland Birth Cohort 1966, a long-running population study administered through the University of Oulu. That means the findings reflect adults from one defined region and age group rather than a nationally representative sample of Finland, the United States, or global coffee consumers. The researchers have not said the results can be generalized without further study in other populations.
Finland is a notable setting for this research because it remains one of the world’s highest coffee-consuming countries. The University of Oulu said average annual consumption there is about 11.8 kilograms, or roughly 26 pounds, per person. That high baseline intake gave researchers a population where meaningful differences in habitual coffee use could be studied at scale.
What is not yet known is whether the same pattern would appear in younger adults, older adults, or people in countries with different diets, activity levels, and coffee habits. The published study focused on observational associations in one cohort at midlife. Researchers also have not issued any recommendation that people start drinking more coffee based on these findings alone.
Hormone patterns may help explain coffee’s broader health links, but causation is unproven
Some of the most striking findings involved sex hormones, especially in men. According to the published study, greater coffee consumption in men was associated with a more favorable glucose-insulin profile, higher total and bioavailable testosterone, and higher sex hormone-binding globulin, or SHBG. At the same time, free testosterone and the free androgen index were modestly lower.
Among women, the hormonal pattern was narrower. Higher coffee intake was mainly associated with increased SHBG and lower measures of free androgens, according to the study and the University of Oulu summary. Lead author Luca Verroest said the research identified a distinct hormonal signature that remained even after accounting for BMI and lifestyle factors, with several associations differing between men and women.
Researchers said those hormone-related findings could help explain why coffee has been linked in earlier studies with better metabolic health. Still, the paper was observational, so it cannot determine cause and effect. The University of Oulu said scientists are now studying whether coffee itself drives these biological changes in animal models, with the longer-term goal of moving toward human intervention studies before any dietary guidance changes.