High-protein diets may be linked to gut inflammation due to increased production of hydrogen sulfide (H2S), a potential toxin, as an end product of microbial fermentation in the colon by sulfidogenic sulfate-reducing bacteria (SRB). We hypothesized that dietary content of sulfur-containing amino acids (SAA) leads to variation in the relative abundances of intestinal SRB, which include Desulfovibrio and Bilophila taxa. To test this hypothesis we performed a pilot crossover study in four healthy volunteers, who consumed two interventional diets for 10–14 days, containing high or low SAA content. The total energy intake was similar between the two dietary extremes. Microbial communities were characterized by 16S rRNA gene amplicon and shotgun next-generation DNA sequencing. While the relative abundance of Desulfovibrio differed among participants (ANOVA P= 0.001), we could not detect a change with dietary treatments. Similarly, no differences in Bilophila abundance were observed among individuals or dietary arms. Inter-personal differences in microbial community composition and functional gene categories differed between subjects and these differences were maintained over the course of the study. These observations are consistent with re-analysis of two previously published dietary intervention studies. Finally, we found that inter-personal differences in the taxonomic composition of fecal microbiota, including the relative abundances of SRB, were maintained over time in 19 healthy individuals in our stool donor program. These results suggest that the use of dietary interventions alone may be insufficient for rapid therapeutic targeting of SRB. Nevertheless, these pilot data provide a foundation to inform future, statistically powered, studies.
Bibliographical noteFunding Information:
A. Dostal Webster is an employee of the International Food Information Council (IFIC) and the IFIC Foundation, which are primarily supported by the broad-based food, beverage, and agricultural industries. This research was completed prior to her employment at IFIC. None of the other authors have any conflicts to declare.
Allen Foundation (MJS and AK); Healthy Foods, Healthy Lives (AK); Achieving Cures Together (AK); Hubbard Broadcasting Foundation (AK).
© 2018, © 2018 Taylor & Francis Group, LLC.
- 16S rRNA gene
- Sulfate-reducing bacteria
- dietary sulfur
- shotgun metagenomics