The research article entitled ‘Association between coffee intake and skeletal muscle mass among U.S. adults: a population-based study’ explores the relationship between coffee consumption and skeletal muscle mass in adults.
Coffee, a beverage rich in caffeine and polyphenols, has antioxidant and anti-inflammatory properties.
The cross-sectional study was based on a sample of 8,333 participants selected from the National Health and Nutrition Examination Survey (NHANES). Measurements of skeletal muscle mass were obtained using two-photon X-ray absorptiometry (DXA) and adjusted for body mass index (ASMBMI). Coffee and caffeine consumption was assessed using a 24-hour dietary recall questionnaire. The association between coffee and caffeine consumption and ASMBMI was analysed using multiple linear regression models and smoothed curve fitting, taking into account demographic variables, energy intake, physical activity and other potentially confounding factors.
The results showed a positive and linear association between coffee (caffeinated or not) and caffeine consumption and an increase in ASMBMI. Participants with a higher consumption of coffee, caffeinated coffee or caffeine showed a higher ASMBMI after adjustment for confounding variables. This relationship persisted in subgroup analyses, except in participants with a BMI greater than 30 kg/m², where the association disappeared, suggesting that obesity could modify this relationship.
This study supports the hypothesis that increased consumption of coffee or caffeine may be beneficial for skeletal muscle mass, particularly in non-obese individuals. Suggested mechanisms include caffeine-induced autophagy, a key process for the maintenance of muscle mass, as well as the anti-inflammatory and antioxidant effects of coffee polyphenols. However, obesity appears to attenuate this effect, which could be due to increased catabolism of lean muscle mass in obese individuals.
Coffee and caffeine consumption is positively associated with skeletal muscle mass in American adults, and could therefore constitute a dietary strategy to prevent loss of muscle mass, particularly in people at risk of sarcopenia. However, further studies, particularly longitudinal ones, are needed to establish a clear causal relationship and explore the implications of these results in obese populations.
