Impact of Glycosidic Bond Configuration on Short Chain Fatty Acid Production from Model Fermentable Carbohydrates by the Human Gut Microbiota

Abstract

Short chain fatty acids (SCFA) are the major products of carbohydrate fermentation by gut bacteria. Different carbohydrates are associated with characteristic SCFA profiles although the mechanisms are unclear. The individual SCFA profile may determine any resultant health benefits. Understanding determinants of individual SCFA production would enable substrate choice to be tailored for colonic SCFA manipulation. To test the hypothesis that the orientation and position of the glycosidic bond is a determinant of SCFA production profile, a miniaturized in vitro human colonic batch fermentation model was used to study a range of isomeric glucose disaccharides. Diglucose α(1-1) fermentation led to significantly higher butyrate production (p < 0.01) and a lower proportion of acetate (p < 0.01) compared with other α bonded diglucoses. Diglucose β(1-4) also led to significantly higher butyrate production (p < 0.05) and significantly increased the proportions of propionate and butyrate compared with diglucose α(1-4) (p < 0.05). There was no significant effect of glycosidic bond configuration on absolute propionate production. Despite some differences in the SCFA production of different glucose disaccharides, there was no clear relationship between SCFA production and bond configuration, suggesting that other factors may be responsible for promoting selective SCFA production by the gut microbiota from different carbohydrates.

Causal roles of mitochondrial dynamics in longevity and healthy aging

“…A major flow of metabolic signals from the gut microbiome to the host is through short‐chain fatty acids (SCFAs) and molecules comprised of SCFAs . SCFAs are the primary metabolites produced by the gut microbiota through the fermentation of nondigestible carbohydrates (NDCs) in humans . Butyrate and acetate, the two major SCFAs, can be converted into acetyl‐CoA to fuel mitochondrial tricarboxylic acid cycle and have been shown to affect mitochondrial biogenesis, metabolism, and dynamics .…”

Dietary Fibres Differentially Impact on the Production of Phenolic Acids from Rutin in an In Vitro Fermentation Model of the Human Gut Microbiota

“…One aliquot was used for pH determination with a calibrated pH meter (Hannah pH20 instruments, USA). Aliquots for SCFA analysis were alkalized to pH > 9 prior to storage [ 38 , 40 ].…”

“…Each vial contained 42 mL of fermentation medium at pH 7.0, 2 mL of reducing solution and 1 mL of rutin aqueous solution (1 mg/mL) or water for blanks [38]. In some cases, the size of the fermentation model was scaled-down by half due to low donor faecal sample weight.…”

“…After full decolouration of the medium, we inoculated with 5 mL of faecal slurry (total volume 50 mL) and incubated in a shaking bath at 37 • C, 60 strokes/min and sampled at 0 h, 6 h and 24 h. Aliquots (5 × 1 mL) were collected with a syringe and needle through the self-sealing septa at each timepoint and stored at −80 • C. One aliquot was used for pH determination with a calibrated pH meter (Hannah pH20 instruments, USA). Aliquots for SCFA analysis were alkalized to pH > 9 prior to storage [38,40].…”

Using misleading online media articles to teach critical assessment of scientific findings about weight loss

“…Because energy excretion in feces is a relatively small quantity and relatively stable across time, then the primary factor dictating metabolizable energy intake is the quantity of energy ingested. A caveat to this is the assumption that nutrients are absorbed across the intestine as the same nutrient that was ingested, which may not be the case with fermentable carbohydrates that can be converted to short-chain fatty acids by the gut microbiome (13). The importance of the gut microbiome in harvesting energy from ingested food and thus its role in energy balance is increasingly appreciated (26).…”