Fermentation of prebiotics by human colonic microbiota in vitro and short‐chain fatty acids production: a critical review

Abstract

Summary Prebiotics are known for their health benefits to man, including reducing cardiovascular disease and improving gut health. This review takes a critical assessment of the impact of dietary fibres and prebiotics on the gastrointestinal microbiota in vitro. The roles of colonic organisms, slow fermentation of prebiotics, production of high butyric and propionic acids and positive modulation of the host health were taken into cognizance. Also, the short‐chain fatty acids (SCFAs) molecular signalling mechanisms associated with their prebiotic substrate structural conformations and the phenotypic responses related to the gut microbes composition were discussed. Furthermore, common dietary fibres such as resistant starch, pectin, hemicelluloses, β‐glucan and fructan in context of their prebiotic potentials for human health were also explained. Finally, the in vitro human colonic fermentation depends on prebiotic type and its physicochemical characteristics, which will then affect the rate of fermentation, selectivity of micro‐organisms to multiply, and SCFAs concentrations and compositions.

Dietary Fiber Modulates the Fermentation Patterns of Cyanidin-3-O-Glucoside in a Fiber-Type Dependent Manner

“…The results of Harris et al on butyric acid production of different DFs in the mid fermentation were similar to ours [ 61 ]. However, in the mid-late fermentation, β-glucan and FOS did not produce significantly higher butyric acid, as shown in a previous study [ 62 ], which may due to the changes the metabolic preference of microorganisms affecting by C3G. In addition, the amounts of isobutyric, isovaleric, and valeric acid ( Figure 8 D–F) were very low.…”

Impact of Plant-Based Meat Alternatives on the Gut Microbiota of Consumers: A Real-World Study

“…One of the greatest challenges in defining “a healthy gut” is that most of the variance (~85%) within the human microbiome is still unaccounted for, as confirmed by population-wide studies [ 76 , 77 ]. However, the relative abundance of microbes able to ferment non-digestible substrates such as dietary fibres to produce short-chain fatty acid (SCFAs) continues to be one of the indisputable criteria for such a definition [ 78 , 79 , 80 , 81 , 82 ]. Of the major SCFAs produced—acetate, propionate and butyrate—butyrate is particularly important for the simple reason that it constitutes the main energy source for colonocytes [ 83 ].…”

Enhancing Micronutrients Bioavailability through Fermentation of Plant-Based Foods: A Concise Review

“…Certain studies have confirmed that fermentation increased the GI [67][68][69], although some evidence indicates that GI decreased [70,71]. The low glycemic index of fermented foods may be due to the microbial conversion of glucose to short-chain organic acids such as propionic acid, acetic acid and lactic acid, which reduces the amount of glucose that is absorbed into blood circulation [72,73]. Ostman et al [74] also suggested another mechanism for the lowering of glucose, which involves pH reduction by the lactic acid and consequent reduction in the activity of starch-hydrolyzing enzymes [74].…”

“…This mechanism may be one of the reasons that sourdough bread reduces the postprandial glucose concentration and enhances glucose homeostasis in a healthy individual. Based on these data interpretations, it is reasonable to conclude that the natural fermentation of sugars and starch lead to formation of propionic and lactic acids that decrease glucose level in foods, which leads to low GI [71,73,75].…”