Effect of probiotic yogurt on short-chain fatty acids, inflammation, and oxidative stress biomarkers: A systematic review and meta-analysis of randomized controlled trials

• Probiotic yogurt consumption showed a significant increase in fecal acetate levels. • There were significant subgroup differences between crossover and parallel trials. • The outcomes presented low or very low certainty of the evidence. • Secondary analysis revealed a significant effect on IL-10. Short-chain fatty acids (SCFAs) production by fermented foods is a promising health strategy regarding inflammation and oxidative stress regulation. However, there is uncertainty whether probiotic yogurt is truly superior to conventional yogurt. This systematic review and meta-analysis aimed to evaluate current evidence on the effect of probiotic yogurt on SCFAs, oxidative stress, and inflammatory biomarkers. A systematic literature search was performed up to December 2025 on PubMed, Scopus, Embase, Web of Science and LILACS. Only randomized controlled trials and crossover studies were included. A random-effects meta-analysis of standardized mean difference (SMD) was performed. A total of 15326 articles were selected. After full-text review, 33 trials were considered. Pooled analysis showed a statistically significant increase in fecal acetate levels (SMD 0.29; 95% CI: 0.02; 0.57). No significant differences were found for propionate, butyrate, and total SCFAs. Subgroup analysis revealed significant differences between study design in acetate and butyrate. Similarly, no significant difference was found for C-reactive protein (SMD -0.61; 95% CI: -2.25; 1.03) and oxidative stress biomarkers. In contrast, interleukin-10 showed a significant increase (SMD 0.48; 95% CI: 0.15; 0.80). Current evidence comparing probiotic yogurt with conventional yogurt is very limited. Preliminary findings suggest increments of clinically uncertain relevance in fecal acetate levels and interleukin-10. However, due to the very low certainty of the evidence, superiority over conventional yogurt is uncertain. Further trials are needed to standardize follow-up time, doses and to address possible effect modification by study design. Registration: PROSPERO registration number: CRD42024534718