Coffee consumption may be associated with a healthier pattern of body fat, muscle mass and metabolic regulation, according to a Finnish study that also identified notable differences between men and women in the way coffee intake relates to sex hormones. The findings, drawn from more than 2,000 adults in the Northern Finland Birth Cohort 1966, suggest that coffee’s biological effects may extend beyond caffeine’s familiar influence on alertness and could involve pathways connected to insulin sensitivity, amino-acid metabolism and hormone transport.
Researchers at the University of Oulu analysed data from 2,264 participants, all aged 46, to investigate whether habitual coffee consumption was linked to circulating metabolites, cardiometabolic risk markers and reproductive hormones. The participants belonged to a long-running population cohort that has followed individuals born in northern Finland since 1966. Because the study included detailed information about body composition, lifestyle and biochemical measurements, the researchers were able to examine relationships between coffee intake and several biological systems at the same time.
One of the clearest findings concerned body composition. People who reported drinking more coffee generally had lower amounts of total body fat and visceral fat than those who consumed less, despite having similar body mass indexes. Visceral fat is stored around internal organs and is considered metabolically active; excess amounts are associated with inflammation, impaired insulin action and a higher risk of cardiometabolic disease. The higher-consumption group also had greater skeletal muscle mass, a result that may indicate differences in energy metabolism or lifestyle that are not captured by BMI alone.
BMI is widely used to classify people according to weight relative to height, but it cannot distinguish fat from muscle or reveal where fat is stored. Two people with the same BMI can therefore have substantially different metabolic risk profiles. The Finnish findings underline why more detailed measures of body composition can provide information that conventional weight-based metrics miss. However, the researchers do not interpret the results as proof that coffee directly reduces visceral fat or builds muscle. Coffee drinkers may differ from non-drinkers in other ways, and even carefully adjusted observational studies cannot eliminate every possible source of confounding.
The study also identified a common metabolic signature in both men and women. Higher coffee consumption was associated with lower circulating concentrations of branched-chain amino acids, a group that includes leucine, isoleucine and valine. These amino acids are essential nutrients involved in protein synthesis and energy metabolism, but persistently elevated levels in the bloodstream have been linked in previous research with insulin resistance and an increased risk of type 2 diabetes. Abnormal branched-chain amino-acid metabolism may reflect changes in how the body processes nutrients, although the present study cannot determine whether coffee intake caused the lower concentrations.
The strongest associations appeared among men. Higher coffee consumption was linked to a more favourable glucose–insulin profile, suggesting better regulation of blood sugar and insulin signalling. Coffee intake was also associated with higher concentrations of total testosterone, bioavailable testosterone and sex hormone-binding globulin, or SHBG. SHBG is a transport protein produced primarily by the liver that binds sex hormones in the bloodstream and regulates how much of those hormones remains available to tissues.
At the same time, men who consumed more coffee had modestly lower free testosterone and a lower free androgen index. This may appear contradictory because total testosterone was higher, but the difference reflects the complex relationship between hormone production and hormone transport. When SHBG levels rise, more testosterone can become bound in the circulation, leaving a smaller proportion unbound or biologically available in some tissues. Total hormone measurements and free-hormone measurements therefore provide different information and may move in opposite directions.
Among women, the hormonal associations were more limited. Higher coffee intake was primarily linked to increased SHBG and lower measures of free androgens. Androgens are often described as male hormones, but they are also produced and used in women, where they contribute to sexual function, bone health, muscle biology and other physiological processes. The sex-specific pattern observed in the study suggests that coffee consumption may interact with hormonal regulation differently depending on sex, although the researchers emphasise that the mechanisms remain uncertain.
“Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones,” said Luca Verroest, the study’s lead author and a doctoral researcher at the University of Oulu. He said the most striking feature of the results was a distinct hormonal signature that remained visible even after accounting for BMI and lifestyle factors, with several associations differing between men and women. The findings raise the possibility that hormonal pathways partly contribute to the relationship between coffee consumption and metabolic health.
Coffee contains hundreds of biologically active compounds, including caffeine, chlorogenic acids, diterpenes and other substances that may influence glucose regulation, inflammation, liver metabolism and hormone-related pathways. Caffeine can affect the nervous system and energy expenditure, while chlorogenic acids have been investigated for their possible effects on glucose absorption and metabolism. The Finnish study did not establish which compounds were responsible for the observed associations, nor did it determine whether preparation methods, serving size, caffeine content or additions such as sugar and cream altered the results.
The research is particularly relevant in Finland, where coffee consumption is among the highest in the world and annual intake averages approximately 11.8 kilograms per person. Yet the population’s strong coffee-drinking culture also makes it important to interpret the findings carefully. Participants were assessed at a single age, and their reported consumption reflected habitual behaviour rather than a controlled dietary intervention. People who drink coffee regularly may also differ in sleep patterns, occupation, physical activity, diet, alcohol use, smoking habits or underlying health conditions. Although the researchers adjusted for lifestyle and other factors, residual differences may still influence the results.
The investigators say the findings provide a foundation for future research, including animal experiments and eventually controlled human intervention studies. Such studies will be needed to determine whether coffee itself produces changes in body composition, branched-chain amino-acid metabolism or sex-hormone regulation, and whether those changes translate into lower disease risk. Until then, the results demonstrate associations rather than cause and effect and are not sufficient to support new dietary recommendations. The study, titled “Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland Birth Cohort 1966 study,” was published in the European Journal of Nutrition on 16 July 2026.
Subject of Research: People
Article Title: Associations of habitual coffee intake with testosterone and cardiometabolic markers: the Northern Finland Birth Cohort 1966 study
News Publication Date: 16 July 2026
Web References: https://www.oulu.fi/en/news/study-links-coffee-consumption-metabolic-health-and-sex-hormones
References: https://doi.org/10.1007/s00394-026-04038-z
Keywords: Coffee, caffeine, metabolic health, body composition, visceral fat, skeletal muscle, branched-chain amino acids, insulin resistance, type 2 diabetes, testosterone, sex hormones, SHBG, cardiometabolic health, University of Oulu, Northern Finland Birth Cohort 1966
Tags: amino-acid metabolismbody composition analysisbody fat regulationcardiometabolic risk markersCoffee consumption and metabolic healthFinnish population healthgender differences in coffee effectshormone transport pathwaysinsulin sensitivitylong-term cohort studyreproductive hormonessex hormone levels
