Fiber supplementation in Antibiotic-induced gut dysbiosis (AID)

Antibiotic-induced gut dysbiosis (AID) is a common and serious side effect of antibiotic usage, and finding ways to mitigate this dysbiosis is crucial for therapeutic purposes. This AID can lead to health complications such as inflammatory bowel disease, aberrant immune function, infection, and metabolic disorders. This study proposes that the host’s diet can influence the chemical environment in the gut, leading to changes in the structure and function of the gut microbiome during antibiotic treatment.

Gut dysbiosis is typically characterized by increased aerobic respiratory bacterial metabolism, higher redox potential, and an abundance of Proteobacteria. In this research, the focus is on exploring dietary fiber supplements as potential agents to modify the gut’s chemical environment and reduce this pattern of dysbiosis.

Several recent studies have begun to explore the role of host diet on AID. Diet-derived fibers such as Xanthan gum have been shown to protect from the drop in bacterial diversity seen post-antibiotic treatment. Studies have begun to show that a high-fat, high-sugar Western-style diet can exacerbate AID.

The study involves using defined diets and whole-genome sequencing of the microbiomes in female mice during diet adjustments and antibiotic treatment. The key findings are as follows:

  • Dietary fiber prebiotics significantly lessen the impact of antibiotic treatment on both the composition and function of the microbiome.
  • The presence of fiber results in a reduced abundance of aerobic bacteria and decreases metabolic pathways associated with oxidative metabolism in the gut microbiome.
  • Fiber supplementation before antibiotic treatment resulted in less initial reduction in diversity and better recovery compared to the glucose group.
  • Fiber supplementation during antibiotic treatment provided significant protection during treatment and recovery.
  • Fiber supplementation post-antibiotic treatment led to improved recovery and increased microbial diversity compared to the glucose group.
  • Mice on a glucose diet experienced a significantly greater decrease in alpha diversity after antibiotic administration at both time points.
  • Antibiotics had a larger impact on microbiome composition and function in mice on the glucose diet compared to those on the fiber diet.
  • Glucose supplementation was associated with an increase in bacterial species in the Proteobacteria phylum.
  • By day 5 of the experiment, glucose supplementation led to significant shifts in species composition and function, primarily driven by Proteobacterial species. Fiber supplementation, on the other hand, led to increases in Archaea and Actinobacteria.
  • Archaeal species, which are sensitive to aerobic environments, increased with fiber supplementation, indicating that fiber helps maintain anaerobic conditions in the gastrointestinal tract.
  • Fiber supplementation was associated with increased metabolic pathways assigned to dormancy, carbon fixation, and fatty-acid metabolism. This indicates that glucose and fiber have divergent effects on the bioenergetics of gut bacteria, and this may contribute to the observed differences in taxonomic response.
  • Fiber supplementation was linked to an increase in the expression of carbohydrate-active enzymes (CAZymes) involved in polysaccharide degradation, suggesting that fiber-supplemented mice had more enzymes to contribute substrates for fermentation.
  • Metabolic pathways unique to an anaerobic environment were significantly associated with the fiber group, suggesting that this diet reduces oxygen in the gut and protects against respiratory metabolism. The glucose diet, on the other hand, was associated with catabolic oxidative metabolism, including glycolysis, the TCA cycle, and the pentose phosphate pathway.

This research suggests that dietary fiber may serve as a potential therapeutic approach for AID by modulating bacterial metabolism in the gut. This modulation prevents an increase in redox potential and helps protect commensal microbes during antibiotic treatment. Additionally, the researchers found that supplementing with single purified fibers at 5% composition also benefited microbiome recovery post-antibiotic treatment. These findings suggest that dietary modifications, particularly supplementing with fiber, can have a positive impact on microbiome recovery after antibiotic treatment and can protect from negative antibiotic effects. Importantly, supplementing with fiber at the time of antibiotic administration was as effective as prior to treatment.

Reference: Swathi Penumutchu, Benjamin J. Korry, Katharine Hewlett, Peter Belenky, Fiber supplementation protects from antibiotic-induced gut microbiome dysbiosis by modulating gut redox potential, https://www.nature.com/articles/s41467-023-40553-x