Fecal Short-Chain Fatty Acids (SCFAs) and Their Role in Metabolic Disorders: A Systematic Review

Abstract

Fecal short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, are gut microbial metabolites that influence energy balance, glucose regulation, lipid metabolism, and inflammation. Altered SCFA production has been associated with metabolic disorders, including obesity and type 2 diabetes, but its role remains unclear. This systematic review synthesized evidence from human studies assessing fecal SCFA concentrations and metabolic outcomes. A literature search of PubMed/MEDLINE, Embase, Scopus, and the Cochrane Library (up to June 2025) was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Of 94 records identified, seven studies met the inclusion criteria, including cross-sectional and interventional designs. A total of 1650 participants, excluding meta-analysis, have been compared. Elevated fecal SCFA levels were frequently associated with increased adiposity, inflammation, and gut microbiota dysbiosis, while targeted SCFA supplementation, particularly with propionate or butyrate, improved insulin sensitivity and reduced energy intake. Risk of bias was generally moderate due to small sample sizes and variability in SCFA measurement methods. Overall, fecal SCFAs appear to act as both biomarkers and modulators of metabolic health. Larger, standardized longitudinal studies are required to clarify their causal role and therapeutic potential in obesity, metabolic syndrome, and related conditions.

Keywords: acetate; butyrate; fecal scfas; insulin resistance; metabolic syndrome; obesity; propionate.

Figure 1. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart represents the study selection process