Statistical analysis. Metric data were checked for normal distribution
and were log-transformed if necessary (concentrations of ethylamine in
plasma and L-theanine in erythrocytes). The effects of time, treatment,
and their interaction (time 3 treatment) on the concentration of amino
acids and ethylamine in plasma and erythrocytes were investigated by
ANOVA followed by a post hoc Tukey test for the comparisons of time
points. Kinetic parameters and urinary excretion of amino acids and
ethylamine determined after capsule and tea intake were compared using
a paired t test. If the test of normality failed, Wilcoxons Signed Rank test
was applied instead. For analyzing dose-dependent effects, the AUC70 of
L-theanine in plasma after intake of 50, 100, and 200 mg L-theanine were
compared by ANOVA followed by a post hoc Tukey test. Differences
were considered significant at P < 0.05. Statistical analysis was
performed using SPSS.