Diet-Related Changes of Short-Chain Fatty Acids in Blood and Feces in Obesity and Metabolic Syndrome

SIMPLE SUMMARY: Short-chain fatty acids are produced by the bacteria present in the large intestine. They are digestion products of fiber-containing foods and have many effects. Short-chain fatty acids appear to decrease weight gain and improve diseases related to obesity, with diet being the most important factor that modifies short-chain fatty acid levels in the body. The purpose of this article is to provide an overview and analysis of the variations of short-chain fatty acids in blood and stool in obesity-related conditions, thus helping to monitor these diseases. ABSTRACT: Obesity-related illnesses are one of the leading causes of death worldwide. Metabolic syndrome has been associated with numerous health issues. Short-chain fatty acids (SCFAs) have been shown to have multiple effects throughout the body, both directly as well as through specific G protein-coupled receptors. The main SCFAs produced by the gut microbiota are acetate, propionate, and butyrate, which are absorbed in varying degrees from the large intestine, with some acting mainly locally and others systemically. Diet has the potential to influence the gut microbial composition, as well as the type and amount of SCFAs produced. High fiber-containing foods and supplements increase the production of SCFAs and SCFA-producing bacteria in the gut and have been shown to have bodyweight-lowering effects. Dietary supplements, which increase SCFA production, could open the way for novel approaches to weight loss interventions. The aim of this review is to analyze the variations of fecal and blood SCFAs in obesity and metabolic syndrome through a systematic search and analysis of existing literature.