# Fiber mixtures containing chicory inulin, wheat dextrin, and cellulose, or tapioca dextrin alone, beneficially modulate microbial metabolic activity and composition in short-term colonic simulations

## TL;DR

This study shows that certain fiber mixtures can improve gut health by boosting beneficial bacteria and reducing harmful byproducts in the colon.

## Contribution

The study evaluates novel fiber blends for prebiotic effects in enteral nutrition, focusing on microbial and metabolic outcomes.

## Key findings

- Fiber mixtures increased short-chain fatty acid production and reduced ammonium levels.
- All fiber blends increased beneficial bacteria like Bacteroidetes and Bifidobacterium.
- Fiber mixtures with lower cellulose boosted anti-inflammatory IL-10 levels across donors.

## Abstract

Dietary fiber blends are commonly included in enteral nutrition to support gut health, a key component of Medical Nutrition Therapy. These blends help maintain intestinal integrity and promote a healthy gut microbiota. In this in vitro study, we investigated the prebiotic potential of three combinations of inulin, wheat dextrin, and cellulose, as well as pure tapioca dextrin.

Predigested test products were incubated with fecal suspensions from three healthy donors in a colonic simulation model. Microbial fermentative activity, metabolite production, and composition were analyzed at 0, 6, 24, and 48 h. After 48 h, samples were tested for their effects on intestinal barrier function and cytokine production in a Caco-2/Tohoku Hospital Pediatrics-1 (THP1) co-culture model.

All test products were well fermented, resulting in a significant increase in total short-chain fatty acid (SCFA) production at 48 h (p < 0.05). Individual SCFA levels varied among donors and according to fiber composition. Ammonium levels, which indicate proteolytic fermentation, were significantly decreased. All fiber mixtures and tapioca dextrin increased the abundance of Bacteroidetes, Actinobacteria (including Bifidobacterium), and Firmicutes. Improvements in intestinal barrier integrity and immunomodulatory effects were donor-dependent, with the strongest effects observed in Donor C. Notably, fiber mixtures with lower or no cellulose statistically significantly increased anti-inflammatory interleukin-10 (IL-10) levels across all donors.

Dietary fiber mixtures containing inulin, wheat dextrin, and cellulose, as well as pure tapioca dextrin, demonstrated prebiotic effects and reduced potentially toxic products of proteolytic fermentation. These findings indicate that such fiber mixtures in enteral nutrition may support gut integrity and modulate immune modulation, benefiting patients receiving Medical Nutrition Therapy.