Abstract
Background: Ingestion of dietary fibers (DFs) is a safe and accessible intervention associated with reductions in blood pressure (BP) and cardiovascular mortality. However, the mechanisms underlying the antihypertensive effects of DFs remain poorly defined. This systematic review and meta-analysis evaluates how DFs influence BP regulation by modulating gut microbial composition and enhancing short-chain fatty acid (SCFA) production. Methods: MEDLINE and EMBASE were systematically searched for interventional studies published between January 2014 and December 2024. Eligible studies assessed the effects of DFs or other prebiotics on systolic BP (SBP) and diastolic BP (DBP) in addition to changes in gut microbial or SCFA composition. Results: Of the 3010 records screened, nineteen studies met the inclusion criteria (seven human, twelve animal). A random-effects meta-analysis was conducted on six human trials reporting post-intervention BP values. Prebiotics were the primary intervention. In hypertensive cohorts, prebiotics significantly reduced SBP (-8.5 mmHg; 95% CI: -13.9, -3.1) and DBP (-5.2 mmHg; 95% CI: -8.5, -2.0). A pooled analysis of hypertensive and non-hypertensive patients showed non-significant reductions in SBP (-4.5 mmHg; 95% CI: -9.3, 0.3) and DBP (-2.5 mmHg; 95% CI: -5.4, 0.4). Animal studies consistently showed BP-lowering effects across diverse etiologies. Prebiotic interventions restored bacterial genera known to metabolize DFs to SCFAs (e.g., Bifidobacteria, Akkermansia, and Coprococcus) and increased SCFA levels. Mechanistically, SCFAs act along gut-organ axes to modulate immune, vascular, and neurohormonal pathways involved in BP regulation. Conclusions: Prebiotic supplementation is a promising strategy to reestablish BP homeostasis in hypertensive patients. Benefits are likely mediated through modulation of the gut microbiota and enhanced SCFA production.