Short-chain fatty acids and insulin sensitivity: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of clinical and randomized trials
PubMed 37290429 · doi:10.1093/nutrit/nuad042
What was done
A systematic review and random-effects meta-analysis following PRISMA guidelines examined the effect of short-chain fatty acid (SCFA) interventions on fasting glucose, fasting insulin, and HOMA-IR. Databases (PubMed and Embase) were searched up to July 28, 2022. Clinical studies and trials (including randomized and crossover designs) that measured SCFA concentrations and reported glucose homeostasis parameters were included. Standardized mean differences (SMDs) with 95% confidence intervals were calculated using RevMan 5.4, and risk of bias was assessed with the Cochrane checklist.
What was found
Across 23 included studies, fasting insulin concentrations were significantly reduced in SCFA intervention groups compared to placebo (SMD = -0.15; 95% CI, -0.29 to -0.01; P = 0.04). Studies with confirmed post-intervention increases in SCFAs also showed a significant reduction in fasting insulin (P = 0.008). Elevated SCFA levels compared with baseline were associated with beneficial effects on HOMA-IR (P < 0.00001). There was no significant change in fasting glucose concentrations. Point estimates and confidence intervals for HOMA-IR and glucose were not reported in the abstract.
Why it matters
Interventions elevating short-chain fatty acids appear to modestly improve fasting insulin and insulin resistance markers, supporting the role of gut microbial metabolites in metabolic regulation.
Limits
The total number of participants is not reported in the abstract. Numerical effect sizes and confidence intervals were omitted for HOMA-IR and fasting glucose. The abstract does not specify the types of SCFA interventions (e.g., diet, prebiotic fiber, direct SCFA administration), intervention durations, or participant clinical characteristics.
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