These molecules play important roles in metabolism. However, elevated blood concentrations have been linked to impaired insulin sensitivity and an increased risk of type 2 diabetes.
The metabolic pattern was more pronounced in men, whose coffee consumption was also linked to more favourable indicators of glucose and insulin regulation. In women, the associations were fewer and centred on other markers related to metabolism and body composition.
Does Coffee Increase Testosterone?
The hormonal findings were more complicated.
After adjusting for factors including BMI, level of education, smoking, physical activity and alcohol consumption, the researchers found that each additional daily cup was associated with total testosterone levels that were 0.29 nanomoles per litre higher in men.
Higher coffee consumption was also associated with higher bioavailable testosterone and sex hormone-binding globulin (SHBG), a protein that binds to sex hormones and helps transport them in the blood.
However, the findings do not mean that coffee raises all forms of testosterone. Free testosterone and the free androgen index – a measure calculated from hormone concentrations – were lower.
In women, coffee consumption was associated with higher SHBG concentrations and lower free testosterone and free androgen index values. No significant associations were found with total or bioavailable testosterone.
What the Study Cannot Tell Us
In a university statement, lead author Luca Verroest, a doctoral researcher at the University of Oulu, highlighted the hormonal patterns that persisted after accounting for BMI and lifestyle factors, and how those associations differed between men and women.
Even so, the findings require caution. This was a cross-sectional study, meaning the data were collected at a single point in time. Researchers could not determine which came first or prove that coffee was responsible for the differences observed. The study identified associations, not cause and effect.
Coffee consumption was also estimated using questionnaires. Details such as cup size, bean variety, roast level and brewing method were not recorded, and hormone levels were not measured repeatedly to track changes over time.
The research offers a more complete picture of coffee’s relationship with body composition, metabolism and sex hormones. Whether these associations translate into concrete health benefits will require further testing and more comprehensive studies.
This story originally appeared on WIRED Español and has been translated from Spanish.