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Session: Diet-microbiome Interactions in Health and Disease (Oral 22)

(OR22-04-23) Immunometabolic Effects of Physicochemically-Distinct Dietary Fibers in Adults With Excess Body Weight: Towards Personalized Dietary Fiber Strategies

Monday, July 24, 2023
4:36 PM – 4:48 PM ET
Location:  Commonwealth
Disclosure(s):
Anissa M. Armet, RD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Dietary fibers (DF) elicit clinical benefits, but with significant inter-individual variation. It is unknown if DF strategies can be improved through personalization based on an individual’s gut microbiome. Our objective was to compare the immunometabolic effects of high doses of physicochemically-distinct DFs in adults with excess body weight and determine if individual microbiome signatures predict these effects using machine learning.

Methods: In a six-week, parallel-arm, randomized controlled trial, adults with BMI 25–35 kg/m2 added 25g (females) or 35g (males) of one of three DFs to their usual diet daily: acacia gum (AG; soluble fermentable; n=75), resistant starch type 4 (RS4; insoluble fermentable; n=75), or microcrystalline cellulose (MCC; insoluble non-fermentable control; n=45). A multi-omics approach was applied to assess clinical markers and microbiome composition, genes, and metabolism. Linear mixed models were used to assess changes from baseline.

Results: AG increased Bifidobacterium longum and Faecalibacterium spp., while RS4 increased Bifidobacterium adolescentis and Parabacteroides distasonis (q < 0.001). Both AG and RS4 increased fecal acetate and total short-chain fatty acids (SCFA) and reduced fecal pH (p < 0.05). AG also increased propionate (p=0.007) while RS4 increased butyrate (p=0.016). MCC had no effect on microbiome composition or SCFAs. RS4 increased the anorexigenic hormone peptide YY (mean change +33%, p < 0.001) and AG decreased the orexigenic hormone ghrelin (–5%, p=0.011). Both AG (–18%, p < 0.001) and MCC (–14%, p=0.002) reduced fecal calprotectin, a marker of gut inflammation. All fibers reduced plasma lipopolysaccharide binding protein (–7% to –12%, p < 0.05), suggesting improved gut barrier function. Coefficients of variation in immunometabolic markers were 30–243%, signifying large variation in responses to the DFs.

Conclusions: AG, RS4, and MCC have discrete effects on microbiome composition, SCFAs, and immunometabolic markers, but with significant inter-individual variation. We are exploring if baseline microbiome signatures and other metadata can predict clinical outcomes using machine learning; if successful, this will help establish a framework to improve health through personalized DF use.

Funding Sources: JPI HDHL; Alberta Innovates and Killam scholarships (awarded to A.A.)