Differences in Gut Microbiota Following a High-Fiber Diet During Pregnancy. (29th May 2020) - Herman, Amy
Abstract: Objectives: To assess the effect of a high fiber diet on changes in gut microbiota and gestational weight gain. Methods: Women were block randomized to a 12-week high-fiber (HF; ≥30g/day) intervention (n = 12) or usual care (n = 8). The HF group met weekly for phone counseling with a Registered Dietitian to learn ways in increase fiber intake and given HF snacks (10-12g/day) for the first six weeks. Three 24-hour dietary recalls were performed (baseline, 6 weeks, and 12 weeks). Body weight and stool were collected at baseline and 12 weeks. Gestational weight gain was calculated by subtracting the end study body weight from baseline. Microbial composition was determined by sequencing the 16S rRNA gene targeting the V3-V4 region using MiSeq. Taxa assignment was based on 97% similarity to the Greengenes database and rarefaction were performed with QIIME2. Three measures of alpha diversity were evaluated. T-tests evaluated differences in microbial changes between groups. Pearson's correlations related relative abundance of bacteria to gestational weight gain. Results: During the study, the HF group had greater fiber intake (26.1 vs 16.7g; P = 0.02), and gained less weight (5.2 vs 6.6kg; P = 0.11). For alpha diversity, the change in number of observed species and whole tree phylogenetic diversity were different between groups ( P = 0.002 and P = 0.004, respectively). No between group differences for change in Shannon Index was found. Taxa from the family Veillonellaceae and genus Dialister were different between groups ( P < 0.05). Differences for families Tannerellaceae and Acidaminococcaceae and genera Parabacteroides and Phascolarctobacterium approached significance ( P = 0.08-0.09). In the fiber group only, correlations between gestational weight gain and change in Bacteroides (r = -0.586, P = 0.06) and Parabacteroides (r = -0.580, P = 0.10) approached significance. Conclusions: After a high-fiber intervention, pregnant women increased fiber intake and gut microbiota alpha diversity, leading to less gestational weight gain. Changes in several taxa at the family and genus level were different between the groups. A larger study is needed to further explore these relationships. Funding Sources: This study was supported by a NIH Clinical and Translational Science Award.