Srinagar, Aug 20: Regular coffee consumption was associated with lower body fat, greater muscle mass and differences in sex hormone levels in a Finnish study, suggesting that coffee may have effects on metabolism beyond its well-known ability to increase alertness.
Researchers at the University of Oulu examined data from 2,264 people aged 46 who were part of the Northern Finland Birth Cohort 1966. They looked at participants’ usual coffee intake and compared it with measures of body composition, metabolic health, circulating metabolites and sex hormones.
People who reported drinking more coffee generally had less total body fat and visceral fat, while also having greater skeletal muscle mass. Notably, these differences were observed even though participants with different levels of coffee consumption had similar body mass indexes.
Higher coffee intake was also linked to lower concentrations of branched-chain amino acids in both men and women. Persistently elevated levels of these amino acids have previously been associated with insulin resistance and an increased risk of type 2 diabetes.
The researchers also found differences in hormone profiles, particularly among men. Greater coffee consumption was associated with a more favorable glucose-insulin profile, higher total and bioavailable testosterone and higher levels of sex hormone-binding globulin (SHBG). At the same time, free testosterone and the free androgen index were lower.
Among women, the hormonal associations were less extensive. Higher coffee intake was mainly linked to increased 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,” said Luca Verroest, lead author of the study and a doctoral researcher at the University of Oulu.
“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,” he added.
The researchers said the hormonal changes could provide clues to previously observed links between coffee consumption and a lower risk of metabolic diseases, including type 2 diabetes. However, the study was observational and therefore cannot show that coffee itself caused the differences.
The findings are particularly notable in Finland, one of the world’s highest coffee-consuming countries, where average annual consumption is about 11.8 kilograms per person.
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.
The researchers said further studies, including experimental and human intervention research, are needed to determine whether coffee directly causes the observed changes and which compounds may be responsible.
