Pulses are healthy and sustainable but induce gut symptoms in people with a sensitive gut. Oats, on the contrary, have no fermentable oligo- di-, monosaccharides and polyols compounds and are known for the health effects of their fibres. This 4-day cross-over trial investigated the effects of oat and rice flour ingested with pulses on gut symptoms and exhaled gases (4th day only) in subjects with a sensitive gut or IBS (n 21) and controls (n 21). The sensitive group perceived more symptoms after both meals than controls (P = 0·001, P = 0·001). Frequency, intensity or quality of the symptoms did not differ between meals during the first 3 d in either group. More breath hydrogen was produced after an oat than rice containing meal in both groups (AUC, P = 0·001, P = 0·001). No between-group difference was seen in breath gases. During day 4, both sensitive and control groups perceived more symptoms after the oat flour meal (P = 0·001, P = 0·0104, respectively) as mainly mild flatulence. No difference in moderate or severe symptoms was detected. Increased hydrogen production correlated to a higher amount of perceived flatulence after the oat flour meal in both the sensitive and the control groups (P = 0·042, P = 0·003, respectively). In summary, ingestion of oat flour with pulses increases breath hydrogen levels compared with rice flour, but gastrointestinal symptoms of subjects sensitive to pulses were not explained by breath hydrogen levels. Additionally, consumer mindsets towards pulse consumption and pulse-related gut symptoms were assessed by an online survey, which implied that perceived gut symptoms hinder the use of pulses in sensitive subjects.

Consumption of resistant starch (RS)-enriched foods is associated with decrease in the postprandial glycaemic and insulinaemic responses, accompanied by the production of fermentation-related gases in the large bowel. The present study aimed to determine the postprandial glycaemic and insulinaemic responses to the GM RS-enriched rice and the fermentation-related production of H2 in young and healthy Chinese adults. A total of sixteen young adults (nine men and seven women) were recruited and divided into three groups. Their postprandial glycaemic and insulinaemic responses to 40 g glucose, carbohydrates of RS or wild-type (WT) rice were tested by a crossover model with a washout period of 7 d. The concentrations of blood glucose and insulin as well as breath H2 were measured before and after food intake. Although the mean concentrations of fasting blood glucose, insulin and breath H2 were similar, consumption of the RS rice significantly decreased the values of glycaemic index (GI) and insulin index (II), as compared with the intake of WT rice (48·4 (sem 21·8) v. 77·4 (sem 34·9) for GI, 34·2 (sem 18·9) v. 54·4 (sem 22·4) for II, P < 0·05), respectively. Conversely, intake of the RS rice meal significantly elevated the concentrations of breath H2, as compared with WT rice (38·9 (sem 17·6) v. 10·5 (sem 3·7) parts per million for peak levels of breath H2, P < 0·05) through a period of 16-h tests. Consumption of the GM RS-enriched rice meal decreased the postprandial glycaemic and insulinaemic responses and promoted RS fermentation-related production of H2 in the large bowel of young and healthy Chinese adults.

There is a need for studies on colonic fermentation in order to learn more abouthealth and diseases of the colon. The aim of the present study was to evaluate the fate of twodifferent doses of fructo-oligosaccharides (5 and 15 g/d) v. glucose in the intestine of healthy men. Twenty-four volunteers participated in a 5-weekstudy. The study was a completely balanced multiple crossover trial using an orthogonal Latin-square design for three periods, with supplement periods of 7 d and two 7 d wash-out periods. Breath samples and faecal samples were collected. There was a clear gaseous response to the consumption of fructo-oligosaccharides. The highest dose significantly increased 24 h integratedexcretion of breath H2 (P < 0·05). Breath H2 excretion after ingestion of 5 g fructo-oligosaccharides was higher than control, but did not reach significance. No effects on the total concentration of short-chain fatty acids in faeces were observed, no modification of the molar proportions of the various short-chain fatty acids was observed. The faecal pH did not change. No changes in faecal weight were observed. No fructo-oligosaccharides were recovered in faeces. We conclude that fructo-oligosaccharides added to the diet of young Western subjects are fully metabolized in the large intestine. The level of fermentation seems to be dose-dependent.

The effect of eating chocolate containing sugar alcohols as sweetening agents on colonic fermentation has been investigated by monitoring breath H2 levels. Levels were compared with those occurring after the consumption of normal, sugar-containing chocolate. Ten healthy volunteers aged 19 to 21 years ingested equal amounts of either sorbitol, isomalt or sucrose incorporated into standard chocolate bars. Breath H2 levels after consumption of chocolate containing either sorbitol or isomalt were significantly higher than those after consumption of chocolate containing sucrose (P < 0.001). After consumption of chocolate containing sorbitol, double the mean estimated volume of breath H2 was produced over 6 h compared with that produced after eating chocolate containing isomalt. Taken together with results relating to the incidence of intolerance symptoms, these findings demonstrate that sorbitol is associated with greater colonic fermentation compared with isomalt.