Gastrointestinal effects of resistant starch, soluble maize fibre and pullulan in healthy adults.

Fibre has been shown to exert a number of benefits on gastrointestinal (GI) health, yet its intake is low. Addition of novel fibres to food products may increase fibre intake and improve gut health. The objective of the present study was to evaluate the influence of three novel fibres on GI outcomes in healthy human subjects. A total of twenty healthy participants (ten men and ten women) with normal BMI (23 (sem 2) kg/m2) participated in the present randomised, double-blind, cross-over study with five treatment periods. Participants consumed a maltodextrin control or 20­25 g/d fibre from soluble maize fibre (SCF) or resistant starch (RS), alone or in combination with pullulan (SCF+P and RS+P). The treatment periods were 7 d with a 3-week washout between the periods. Stool samples were collected on day 7 of each period, and GI tolerance was assessed via a questionnaire on days 1 and 6. There were no treatment differences in stool weight or consistency. SCF significantly reduced stool pH and increased total SCFA production compared with RS and control. RS+P significantly increased the percentage of butyrate compared with all the other treatments. Overall, GI symptoms were minimal. SCF+P led to the highest GI score on day 1, while RS+P had the highest score on day 6. Both SCF treatments caused a significant shift in the gut microbial community. These functional fibres are generally well tolerated, have minimal effects on laxation and may lead to beneficial changes in SCFA production in healthy adults.

Estimation and interpretation of fermentation in the gut: coupling results from a 24 h batch in vitro system with fecal measurements from a human intervention feeding study using fructo-oligosaccharides, inulin, gum acacia, and pea fiber.

Gut bacteria ferment fiber at different rates to primarily short chain fatty acids (SCFA) and gas while proteins are metabolized to SCFA, branched chain fatty acids (BCFA), gas, and undesirable metabolites. Large volumes of gas produced in vivo may contribute to bloating and flatulence in an individual. The objectives of this trial were to (1) compare the in vitro fermentation profiles of fructo-oligosaccharides (FOS), inulin, gum acacia, and pea fiber alone or blended using a 24 h batch model and (2) relate these findings to a human study that fed enteral formula fortified with fiber blend (FB) or no fiber (FF). The in vitro fermentation of the fiber blend resulted in a delayed pH decrease and gas and SCFA production compared to the FOS and inulin. Human samples had higher SCFA on FB compared to FF (p = 0.029). BCFA were not different between formulas. By using a blend of fibers, we observed a slower fermentation in vitro but still increased fecal SCFA when fed to human subjects.

Resistant starch and pullulan reduce postprandial glucose, insulin, and GLP-1, but have no effect on satiety in healthy humans.

The aim of this study was to determine the effects of three novel fibers on satiety and serum parameters. In a randomized, double-blind, crossover design, fasted subjects (n=20) consumed a low-fiber control breakfast or one of four breakfasts containing 25 g of fiber from soluble corn fiber (SCF) or resistant starch (RS), alone or in combination with pullulan (SCF+P and RS+P). Visual analog scales assessed appetite, and blood samples were collected to measure glucose, insulin, ghrelin, and glucagon-like peptide-1 (GLP-1). The fiber treatments did not influence satiety or energy intake compared to control. RS+P significantly reduced glucose, insulin, and GLP-1, but neither SCF treatment differed from control. To conclude, these fibers have little impact on satiety when provided as a mixed meal matched for calories and macronutrients. Additional research regarding the physiological effects of these novel fibers is needed to guide their use as functional ingredients in food products.