Effects of coffee consumption on salivary cortisol and alpha amylase in young adults

Abstract

Objective: The purpose of this study was to determine the effects of coffee consumption on salivary cortisol (sCort) and alpha amylase (sAA) in young adults. Materials and methods: Sixty healthy university students, habitual coffee consumers, participated in this descriptive observational study. Participants were divided into three groups: G1 low consumption (≤ 2 cups of coffee per day, n= 20), G2 moderate consumption (2-5 cups of coffee per day, n = 20), and G3 high consumption (>5 cups of coffee per day, n = 20). Saliva self-collection was in the morning (6:30-7:30 AM) and at night (08:00-09:00 PM). sCort was analyzed using chemiluminescence and sAA activity by kinetic method. Statistical analysis of the data was performed using Student's t-test and analysis of variance. Results: The sample consisted of 30 women and 30 men, aged between 20 and 35 years. In all groups, sCort values were higher in the morning (AM 0,29 ± 0,19 vs. PM 0,09 ± 0,05 μg/dl, p < 0.0001). In contrast, sAA levels were higher in the night (PM 160,16 ± 60,42 vs. AM 32,79 ± 12,98 U/ml, p < 0.0001). No significant differences were detected, in the contents of Corts and AAs, between the groups. Conclusion: Coffee consumption, in non-stressful conditions, did not alter levels and patterns of sCort and sAA in young adults.