Increased Butyrate Production During Long‐Term Fermentation of In Vitro‐Digested High Amylose Cornstarch Residues with Human Feces

Abstract

An in vitro semi-continuous long-term (3 wk) anaerobic incubation system simulating lower gut fermentation was used to determine variability in gut microbial metabolism between 4 predigested high amylose-resistant starch residues (SR): SRV, SRVI, SRVII, and SRGEMS in human fecal samples. Subjects participated twice, 5 mo apart: 30 in Phase I (15 lean, 9 overweight and 6 obese), 29 in Phase II (15 lean, 9 overweight, 5 obese); 13 of 15 lean subjects participated in both phases. Of the 4 SRs, SRV displayed the highest gelatinization temperature, peak temperature, enthalpy changes, and the least digestibility compared with the other SRs. In both phases, compared with blank controls, all SRs increased butyrate ∼2-fold which stabilized at week 2 and only SRV caused greater propionate concentration (∼30%) after 3 wk which might have been partly mediated by its lesser digestibility. Fecal samples from lean and overweight/obese subjects incubated with SRs showed similar short-chain fatty acid production across both time points, which suggests that resistant starch may benefit individuals across BMIs.

Acute increases in serum colonic short-chain fatty acids elicited by inulin do not increase GLP-1 or PYY responses but may reduce ghrelin in lean and overweight humans

“…The results of other human studies are inconsistent in this respect, as reviewed elsewhere ( 44 , 45 ). Interestingly, recent in vitro fermentation studies using faecal inocula from lean vs. obese donors showed that 4 different types of RS produced similar SCFA concentrations in LN and OWO inocula ( 46 ), while other types of fibre showed either increased or decreased SCFA production in OWO compared to LN ( 47 ). Therefore, further research is needed to fully elucidate whether the SCFA production and metabolism differ in lean and obese humans.…”

Predictors of Obesity among Gut Microbiota Biomarkers in African American Men with and without Diabetes

“…Butyric and propionic acids were decreased in anorexia nervosa compared to normal weight controls [52]. On the other hand, the ex vivo anaerobic incubation of fecal samples from lean and obese individuals with amylose-resistant starch resulted in similar increased production of butyric and propionic acids [53]. Previous studies showing higher levels of SCFAs in obese compared to lean individuals [13,14,15,16] generated the hypothesis that there might be resistance to SCFAs in obesity.…”