People who drank five or more cups of coffee per day had less body fat and more muscle than those who drank little or no coffee, despite comparable BMIs, according to a study of more than 2,200 middle-aged people in Finland.
The same heavy coffee drinkers, especially men, also showed more total testosterone, but less of the “free” testosterone that cells can actually use.
The study, published July 16 in the European Journal of Nutrition, examined habitual coffee intake in relation to body composition, circulating metabolites, cardiometabolic markers and sex hormones, with several patterns differing between men and women.
“Coffee is consumed by millions of people every day, yet we still know surprisingly little about how it relates to our metabolism and hormones,” Luca Verroest, lead author and a doctoral researcher at the University of Oulu in Finland, said in a university release. “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.”
Read This If You’re 46 and Finnish
The paper was led by researchers at the University of Oulu, with additional affiliations including Poznan University of Medical Sciences, Imperial College London, Brunel University London and Oulu University Hospital.
The study drew from the Northern Finland Birth Cohort 1966, a long-running population study that began with nearly all children born in Northern Finland in 1966.
For this analysis, researchers looked at 2,264 people who took part in clinical exams at age 46, including 2,194 coffee drinkers and 70 non-drinkers. Participants reported how much coffee they typically drank each day, while researchers measured body composition, blood pressure, blood sugar, insulin, cholesterol, hormones and a broad panel of circulating metabolites.
Fat Storage, Blood Work and Hormone Changes
The results do not mean coffee drinkers were simply thinner. Instead, they suggested that coffee drinkers carried less fat and more muscle at roughly similar BMI levels.
The blood-marker picture was more mixed. In both men and women, higher coffee intake was linked to lower levels of branched-chain amino acids. These are protein building blocks that, when chronically elevated in the bloodstream, have been associated with insulin resistance and elevated type 2 diabetes risk. Among men, higher coffee intake was also linked to lower insulin measures and greater insulin sensitivity, but to higher levels of several LDL- and IDL-related cholesterol measures. The study does not show that coffee caused any of those differences.
The hormone results were not as simple as “more coffee, more testosterone.” In men, higher coffee intake was linked to higher total testosterone and higher bioavailable testosterone, but also to higher levels of sex hormone-binding globulin, or SHBG, a protein that helps regulate how sex hormones circulate in the body. Free testosterone and the free androgen index were lower. In women, coffee intake was mainly linked to lower freely available androgen measures.
In plain terms, the study found a different hormone profile among people who drank more coffee, especially men, but it does not show that coffee caused those differences or that they would translate into noticeable hormonal changes for individuals.
Coffee Context
The study adds some nuance to health claims around coffee. Research over the past decade has linked coffee consumption to lower body fat, improved muscle mass in U.S. adults and smaller long-term weight gain, while also repeatedly noting that coffee’s health associations depend on context, including additives, brewing method and overall diet.
More recent DCN coverage has examined coffee’s possible links to blood sugar, type 2 diabetes and cardiovascular risk, including studies suggesting that sweeteners and preparation method can change the picture.
Like several of those studies, the new study is observational and cross-sectional, meaning it cannot establish cause-and-effect relationships between coffee consumption and health outcomes.
The study was supported by the European Union’s Horizon Europe research and innovation program through the Marie Skłodowska-Curie Doctoral Network NUTRIOME. The authors declared no conflict of interest.
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