Introduction: Diet is one of the most influential lifestyle components modulating the composition of the gut microbiome. Of particular interest is the impact of dietary behaviour on maternal microbiome on both pregnancy outcomes and the future health of mother and child alike. Evidence suggests that consuming a Mediterranean diet (MD) can positively impact maternal and offspring health. In a previous work, we found significant differences in the metabolic phenotype of pregnant women who self-reported concordance to a high and low MD. This work expands on these previous findings by examining the impact of MD on the gut microbiome composition and functions in a cohort of pregnant women.
Methods: Stool samples were collected from 48 pregnant women at weeks 20, 28, and 36 of their pregnancy. A questionnaire was used to determine a Mediterranean Diet Index (MDI) and classify the participants according to their alignment with the MD. The microbial composition was assessed by 16S rRNA amplicon sequencing. Diversity and differential abundance analysis were performed to evaluate the impact of the MD on microbial composition. In previous work, Proton Nuclear Magnetic Resonance (1H NMR) was used for the metabolic profiling of serum and urine of the participants at the same time points. Thus, we integrated the datasets to explore the correlation between microbial composition and inflammation metabolic markers.
Results: The microbial composition of the stool samples of participants at weeks 20 and 28 of pregnancy significantly differed between pregnant women with a high MDI and those with a low MDI. However, these differences were no longer significant at week 36. Moreover, the microbial diversity was significantly higher in women with a high MDI. Differential abundance analysis showed that at weeks 20 and 28, the genera Bifidobacterium, Actinomyces, and Lactococcus, among others, were significantly less abundant in the stool sample of the participants with HMDI. We observed significant positive correlations between the taxa Blautia and Dorea with the inflammatory markers GlycA and GlycB.
Conclusions: This work provides evidence of the potential modulatory effect of the MD on the gut microbiome composition and function during pregnancy.