Gut microbiome composition is similar between pregnant women with excess body fat with healthy and less healthy dietary intake patterns.

Background: Dietary composition influences the composition of the gut microbiota in healthy adults. Little is known about the effect of dietary patterns on gut microbiota composition in pregnancy. This cross‐sectional study aimed to investigate the associations between two diet quality scores adapted from the Australian Recommended Food Score (ARFS) and the Mediterranean Dietary Score (MDS) with the composition of the gut microbiota in pregnant women with excess body fat at 28 weeks' gestation. Methods: Women from the Study of Probiotics IN Gestational diabetes (SPRING) who had completed a food frequency questionnaire (FFQ; n = 395) were classified according to tertiles of ARFS and the MDS. Higher dietary pattern scores in both the ARFS and the MDS represent better diet quality. Gut microbiota composition was assessed using 16S rRNA gene amplicon sequencing and analysed using MicrobiomeAnalyst in a subset of 196 women with faecal samples. Results: No significant difference was found in alpha or beta diversity. A higher ARFS was associated with a higher abundance of Ruminococcus and lower abundance of Akkermansia, whereas a higher MDS was associated with a higher abundance of Ruminococcus and Butyricicoccus, though these changes disappeared after correction for multiple testing. Conclusion: These results suggest that dietary patterns defined by the ARFS and MDS were not associated with gut microbiota composition in pregnant women classified as overweight and obese at 28 weeks' gestation within this study. Key points: This is the first study to investigate the relationship between two distinct dietary patterns and gut microbiota composition in women with overweight and obesity at 28 weeks' gestation.Compared with other cohorts, pregnant women's overall diet quality was low; even in the highest tertile of Australian Recommended Food Scores (ARFS), women still had a diet low in nutrients, fibre and diversity of foods eaten. Mediterranean Diet Scores (MDS) had higher means in the nonbeneficial, low‐fibre, component scores of dairy and meat, lower component mean scores in the beneficial, high‐fibre components of fruit and nuts, and vegetables representing a westernised version of the MD pattern.No significant associations were observed between the MDS or ARFS tertiles and overall diversity of the gut microbiota or genus abundance. [ABSTRACT FROM AUTHOR]