Fig. 2

The gut microbiota structure allows stratifying the whole dataset into four distinct clusters. a Hierarchical Ward linkage clustering based on the Spearman correlation coefficients of the relative abundance of OTUs, filtered for presence in at least 20% of the participants. Labeled groups in the top tree (basis for the four groups of Fig. 3) are highlighted by stars colored according to the microbiota configuration (C1–C4) (see d). OTUs are color-coded by family assignment in the vertical tree. Bacteroidetes phylum, blue gradient; Firmicutes, green; Proteobacteria, red; and Actinobacteria, yellow. The bar plot at the bottom shows the relative abundance of the family-classified microbiota profiles. Bar plots showing the percentage of normal-weight (NW) and overweight/obese (OB) women for each cluster (b) and the distribution of the latter in terms of BMI status: overweight (OW), class 1 obesity (OB1), and class 2 obesity (OB2) (c). d Alpha diversity measured using the Shannon index and the number of observed OTUs for the four microbiota clusters (C1–C4). * p < 0.04; ** p < 0.001; *** p < 3 × 10⁻⁴; Wilcoxon rank-sum test