The impact of Uva tea extract capsule consumption on psychological stress: A randomized, double-blind, placebo-controlled, crossover trial

Objectives This study aims to investigate the effects of consuming Uva tea extract capsules by decreasing the psychological stress in Japanese subjects. Methods Twenty-two eligible subjects were randomly assigned to sequences either an Uva tea extract（Uva）or a placebo, with each member in both sequences consuming appropriate capsules. Each intervention lasted for 3 weeks, with the 2-week washout period. We assessed the autonomic nervous activity and mood state of subjects in both sequences. Results The Uva capsule intake revealed trends toward significantly lower the ratio between low and high frequency components and significantly lower tension-anxiety compared with the placebo capsule intake. Furthermore, subjects with the body mass index＜25, especially the Uva capsule intake, exhibited the dominant parasympathetic nervous system. Conclusions Hence, this study suggests that the 3-week Uva capsule consumption could modulate the automatic nervous system and ease tension and anxiety. Trial Registration University Hospital Medical Information Network; UMIN000027549 Foundation There was no funding.