Fig. 3

Effect of linoleic acid on gut microbiota diversity and specific bacterial genera. A Shannon index across linoleic acid tertiles. Median lines, boxes (25 th–75 th percentiles), and whiskers (1.5 times the box length) show data distribution, with outliers marked. P values were from the linear mixed-effects model. Sample sizes (n) are provided for each group. B Principal coordinates analysis of beta diversity index changes during pregnancy across linoleic acid tertiles. P values were from the PERMANOVA. Sample sizes (n) are provided for each group. C Associations of linoleic acid levels with individual gut microbial genera. Significant associations of linoleic acid levels with microbial genera (FDR-adjusted P < 0.25) are presented, which are overlaid onto their taxonomic information. The innermost ring and phylogenetic trees use colors to distinguish major phyla. The height of the outer bars corresponds to the mean relative abundance of each microbial genus. D Associations of genera identified in the joint association analysis with linoleic acid in early and middle pregnancy. E Significant associations between linoleic acid levels and microbial genera are highlighted. All models were adjusted for GDM status (yes and no), maternal age (years, continuous), education (primary or middle school, high school, and college or above), gestational age at baseline blood collection (weeks, continuous), pre-pregnancy BMI (< 18.5, 18.5–24, 24–28, and ≥ 28 kg/m²), and intake of meat (0, ≤ 50, ≤ 100, and > 100 g/day), vegetables and fruits (≤ 50, ≤ 100, ≤ 150, and > 150 g/day), eggs (0, ≤ 1, and > 1/day), and dairy product (0, < 250, and ≥ 250 ml/day). FDR, false discovery rate; GDM, gestational diabetes mellitus; PERMANOVA, permutational multivariate analysis of variance