Sample size and statistical analysis
gastrointestinal sensation
The primary outcome measure was bifidobacterial population as logStatistical Package for Social Science version 27 (SPSS Inc.) was used for all statistical analyses. Assumptions of normality were assessed using Kolmogorov-Smirnov test, Shapiro-Wilk test, and Q-Q plots. To assess differences between interventions at D28 in bacteriology (FLOW-FISH and quantitative microbiome profiling [QMP]), mood state (BDI, STAI, and PANAS-SF), PSQI, CAR, bowel habits, gastrointestinal sensation, and nutrient data, a general linear analysis of covariance (ANCOVA) was performed using intervention as a fixed factor, D28 values as dependent variables, and D0 values, sex, and PHQ-9 and GAD-7 scores as covariates. General linear ANCOVA with intervention as a fixed factor was also applied for bowel habits, gastrointestinal sensation, and nutrient data whereby either D26 to D28 (for nutrient data) or final week scores (for bowel habit and gastrointestinal sensation) were the dependent variables, with D0 to D2 (for nutrient data) run-in week (for bowel habit and gastrointestinal sensation), sex, and PHQ-9 and GAD-7 scores as covariates. Marginal general linear models (MGLMs) were used to assess changes over time (D0 compared with D28) for mood state, PSQI, CAR, and nutrient data as previously described [Correlations between bacterial taxa and mood state were assessed employing fold change ((post-pre)/pre) using nonparametric Spearman’s rank correlation corrected for using false discovery rate (FDR). All tests were 2-tailed and 