Fig. 5

W1 and W2 profile variations. a BMI. When BMI is available, samples are displayed in the W1-W2 space, colored by BMI. 95% confidence ellipse are indicated for BMI lower and higher than 35 (class 2, severe obesity threshold). b Obesity status. Boxplot of W1 and W2 levels structured by obesity status. We can observe that for highest obesity classes, W1 is significantly higher whereas W2 is significantly lower (MW = Mann-Whitney test). This shift can be also observed in the confidence ellipse centroid in subfigure a. c Dysbiosis index. All samples are displayed in barycentric coordinates in the W1-W2 space. Barycentric coordinates are equivalent to compute \(W^*=W^{(AFT)}_{2}\left/\left(W^{(AFT)}_{1}+W^{(AFT)}_{2}\right)\right.\). The extremity \(W^{(AFT)}_{1}\) corresponds to \(W^*=0\), i.e. when only profile 1 is present in the sample, and the extremity \(W^{(AFT)}_{2}\) corresponds to \(W^*=1\), i.e. when only profile 2 is present. Samples are stratified by DI: the first DI decile (gray), non dysbiotic samples (blue, DI<dysbiosis threshold), dysbiotic samples (orange, DI>dysbiosis threshold) and last DI decile (pink) are displayed. The red ticks indicate the group mean, and confidence interval (mean +/- 2*standard deviation) is displayed with a colored bar. The dotted red line indicate the value \(W^*=0.2\). We note a higher \(W_1-W_2\) unbalance for increasingly dysbiotic groups. d Mediterranean diet. Samples are displayed in barycentric coordinates in the \(W_1-W_2\) space for the Mediterranean Diet cohort at baseline (circles) , 4 weeks (trianges) and 8 weeks (stars) after intervention for control (mauve) and Mediterranean diet (brown). The mean of each category is displayed with a red vertical line and confidence intervals are indicated as in plot c. The dotted red line indicate the value \(W^*=0.2\). We can observe that sample variability around the mean is strongly shrunk for the Mediterranean diet group after 4 weeks. e Mediterranean diet stabilises the microbiota. The variance of \(W_2/(W_1+W_2)\) in the control and Mediterranean diet groups is displayed at baseline, 4 weeks and 8 weeks. The variance decreases for Mediterranean diet after 4 and 8 weeks is significant (Levene test). e Time shifts of \(W^*\). Time shifts, defined as the difference of \(W^*= W_2/(W_1+W_2)\) between 4 weeks and 8 weeks, are displayed with boxplots, for the Mediterranean and control diet groups. Time shifts are reduced after intervention for the Mediterranean group, with low significance (\(p = 0.06\), Mann-Whitney one-sided test)