Summary:
Dietary components such as prebiotic fibers, omega-3 fatty acids, and synbiotics may influence immune function and reduce chronic inflammation. Prebiotics are non-digestible fibers that promote the growth of beneficial gut bacteria, which can affect immune responses. Omega-3 fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid, are recognised for their anti-inflammatory properties. Synbiotics combine probiotics (live microorganisms) with prebiotics that support their survival in the gastrointestinal tract, creating a synergistic effect that may enhance health benefits compared with either component alone. Fermented foods such as kefir naturally contain probiotics produced during fermentation. Kefir typically contains a mixture of microorganisms that produce metabolites including peptides, vitamins, amino acids, and short-chain fatty acids, which may influence immune responses and inflammatory processes. This study was a six-week dietary intervention that examined whether nutritional supplements could reduce inflammation. The interventions included omega-3 fatty acid supplementation, prebiotic fiber (inulin), and a synbiotic combining kefir with prebiotic fiber, while a control group received no supplementation. Participants were assigned to the synbiotic group (n= 20), omega-3 group (n= 33), inulin fiber group (n= 31), or control group (n= 20). Blood samples were used to measure changes in markers of systemic inflammation. All three dietary interventions reduced inflammatory markers compared with the control group. Omega-3 supplementation and inulin fiber were associated with reductions in tumour necrosis factor-alpha. The synbiotic intervention produced broader reductions across several inflammatory and immune-related proteins. Increased levels of butyrate, a short-chain fatty acid associated with gut microbial metabolism, were also observed in the synbiotic group. Overall, this study found that all interventions reduced systemic inflammation, although the synbiotic combination produced the most consistent and widespread changes in inflammatory biomarkers. These findings suggest that combining fermented foods with prebiotic fiber may have stronger anti-inflammatory effects than individual dietary components. Future research is needed to examine how synbiotic interventions influence interactions between the gut microbiome and host inflammatory responses.
Abstract:
Background: Understanding how diet influences inflammation requires identifying specific dietary components responsible for anti-inflammatory effects. This study examined the impact of six-week supplementation with a single-source prebiotic fibre (inulin), omega-3, or a synbiotic (fermented kefir + prebiotic fibre mix) on a broad range of inflammatory markers. Methods: Serum inflammatory proteins were profiled using the Olink 96 inflammation panel in a 6-week intervention. Participants received one of the following: synbiotic (n = 20; 170 ml kefir + 10 g prebiotic), omega 3 (n = 33; 500 mg/day), inulin fibre (n = 31; 20 g/day), or no supplementation (n = 20 control). Changes from baseline and between groups were analysed using parametric methods and effect sizes (Cohen’s d). FDR-adjusted p < 0.05 was considered significant. Results: All three dietary interventions significantly reduced inflammatory markers versus control. TNF-α decreased with omega-3 (d= − 0.618, 95% CI -0.73 to -0.09, p = 0.01) and inulin fibre (d=–1.012, 95% CI -0.71 to -0.20, p = 0.001). The synbiotic group showed broader and larger reductions, including IL-6 (d=–0.882,95% CI -1.36 to -0.17, p = 0.01), IFN-γ (d=–0.940, 95% CI -2.03 to -0.31, p = 0.009), SIRT2 (d=–1.505, 95% CI -1.30 to -0.51, p < 0.0001), 4EBP1 (d=–1.384, 95% CI -1.43 to -0.32, p = 0.0004), CCL23 (d=–1.356, 95% CI -1.40 to -0.48, p = 0.0002), and mucosal cytokines CCL25 (d=–1.137, 95% CI -0.90 to -0.23, p = 0.001) and CCL28 (d=–1.006, 95% CI -0.80 to -0.16, p = 0.003). Increases in serum butyrate correlated with reductions in IL-6 following the synbiotic intervention. Conclusions: All interventions reduced systemic inflammation, but the synbiotic produced broader and stronger effects, targeting proteins linked to immune and metabolic function. While gut microbiome profiling was not included in this study, it is planned in future work to clarify how synbiotics may influence host–microbiome interactions and inflammatory regulation.
Article Publication Date: 16/10/2025
DOI: 10.1186/s12967-025-07167-x
