Effects of Regular and Decaffeinated Coffee Consumption on Stress, Anxiety, and Depression in Brazilian Women: A Randomized Crossover Clinical Trial

Background: Coffee is a widely consumed beverage in Brazil that has many antioxidant components with potential anti-inflammatory effects, which can play an important role in the genesis of mental health disorders. Alternatively, caffeine is a psychoactive compound found in coffee that is positively associated with mental health disorders. Depression and anxiety are the main mental disorders, and they are more prevalent in women.  This study aimed to investigate the effects of regular and decaffeinated coffee intake on depression, anxiety and stress levels in women. Methods: This was a 2-week randomized, cross-over trial with 43 women (M_age= 29.92±8.71y) being frequently coffee drinkers. Participants were asked to drink coffee on an empty stomach, followed by a standard breakfast meal. Coffee were consumed in three days changing the preparation of coffee: (i) coffee, (ii) coffee with add sugar, (iii) coffee with whole-milk and (iv) coffee with whole-milk and added sugar. Participants were randomized into regular (n=24) and decaffeinated (n=19) groups. Participants did not consume coffee in the 1^st and 14^th day of the trial to avoid measurement bias. The 21-item Depression Anxiety and Stress Scale (DASS-21) were reported by the participants at baseline and post-intervention period. The Dietary Antioxidant Quality (DAQ) was calculated based on the mean of energy, vitamin A, vitamin C, vitamin E, selenium and zinc from the 3-day 24h recalls at each moment women consumed coffee. T-student test and spearman correlation were calculated, considering a p<0.05 as significant. Results: Differences in intake between regular and decaffeinated coffee from baseline to post-intervention were observed a decrease in mean score for depression (△ -0.08 ±0.39) and increase for anxiety (△ 0.32 ± 1.99) and stress (△ 0.17 ± 0.07). Regular coffee showed a positive weak correlation between total DAQ and depression (rho = 0.09), anxiety (rho = 0.154) and stress (rho = 0.01). Alternatively, decaffeinated presented a negative weak correlation between DAQ and anxiety (rho = -0.14) and stress (rho = -0.14), but positive moderate correlation with depression (rho = 0.33). Conclusion: Decaffeinate coffee showed better effects on total antioxidant diet in anxiety and stress levels than regular coffee, which underscore the potential effects of caffeine in modulating mood and stress. Further studies with more representative sample are needed to better clarify these mechanisms.