People who drink coffee three times a day have greater muscle mass than those who do not, according to a new study. Seoul National University said Thursday that a research team led by Professor Park Sang-min at the College of Medicine found the correlation after analyzing data from the Korea National Health and Nutrition Examination Survey conducted between 2008 and 2011.
The team analyzed 15,447 adults aged 20 and older who had both whole-body dual-energy X-ray absorptiometry (DXA) data and information on coffee consumption frequency. The researchers examined the relationship between coffee consumption frequency and indicators such as the Appendicular Skeletal Muscle Mass Index (ASMI) and the Lean Body Mass Index (LBMI). The LBMI is calculated based on the weight of muscles, bones and organs excluding body fat, and reflects the level of muscle mass relative to body size.
The analysis showed that men who drank coffee three times a day had higher ASMI and LBMI scores than those who drank it less than once a day. Among women, the group consuming coffee three times a day showed a lower Fat Mass Index (FMI) and higher ASMI and LBMI scores than those drinking less than one cup a day.
The researchers said the study illustrates the biological mechanisms linking caffeine to energy metabolism, fat oxidation and muscle function, but noted that it cannot be concluded that coffee directly induces changes in body composition. Caffeine is known to increase adrenaline secretion once absorbed, promoting the release of free fatty acids from adipose tissue and skeletal muscle, and stimulating muscle energy metabolism. A recent Chinese research team also confirmed an association between caffeine intake and muscle mass after analyzing 9,116 adults aged 20 to 59 using data from the U.S. National Health and Nutrition Examination Survey (NHANES). Multiple meta-analyses have also accumulated evidence that caffeine supplementation significantly enhances muscle strength and endurance. However, most of these studies are based on short-term supplementation experiments or cross-sectional surveys, meaning the causal relationship with long-term changes in muscle mass remains unclear.
Jung Ji-na, the first author of the study, said, "We confirmed that coffee consumption frequency can be associated with body composition indicators in Korean adults, particularly those related to muscle mass." She added, "We will continue with follow-up research."
