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Purpose Increasing secretion and production of glucagon-like peptide-1 (GLP-1) by continuous ingestion of certain food components has been expected to prevent glucose intolerance and obesity. In this study, we examined whether a physiological dose (5% weight in diet) of digestion-resistant maltodextrin (RMD) has a GLP-1-promoting effect in rats fed a high-fat and high-sucrose (HFS) diet. Methods Rats were fed a control diet or the HFS (30% fat, 40% sucrose wt/wt) diet supplemented with 5% RMD or fructooligosaccharides (FOS) for 8 weeks or for 8 days in separated experiments. Glucose tolerance, energy intake, plasma and tissue GLP-1 concentrations, and cecal short-chain fatty acids concentrations were assessed. Results After 4 weeks of feeding, HFS-fed rats had significantly higher glycemic response to oral glucose than control rats, but rats fed HFS?+?RMD/FOS did not (approx. 50% reduction vs HFS rats). HFS?+?RMD/FOS-fed rats had higher GLP-1 responses (~twofold) to oral glucose, than control rats. After 8 weeks, visceral adipose tissue weight was significantly higher in HFS-fed rats than control rats, while HFS?+?RMD/FOS rats had a trend of reduced gain (~50%) of the tissue weight. GLP-1 contents and luminal propionate concentrations in the large intestine increased (>twofold) by adding RMD/FOS to HFS. Eight days feeding of RMD/FOS-supplemented diets reduced energy intake (~10%) and enhanced cecal GLP-1 production (~twofold), compared to HFS diet. Conclusions The physiological dose of a prebiotic fiber promptly (within 8 days) promotes GLP-1 production in rats fed an obesogenic diet, which would help to prevent excess energy intake and fat accumulation.

Background: It has been reported that low-viscous and fermentable dietary fiber and nondigestible oligosaccharides enhance mineral absorption. Resistant maltodextrin, nonviscous, fermentable and soluble source of dietary fiber, has several physiological functions. However, influence of resistant maltodextrin on mineral absorption is unclear. Aim of the study: We conducted balance studies in rats to investigate effects of resistant maltodextrin and hydrogenated resistant maltodextrin on apparent mineral absorption. Methods: In experiment 1 (Exp. 1), 40 rats were fed test diets based on AIN-93G with or without resistant maltodextrin or hydrogenated resistant maltodextrin for 2 weeks. In experiment 2 (Exp. 2), 32 rats were cecectomized (CX) or sham-operated (Sham) and fed diets with or without hydrogenated resistant maltodextrin for 1 week. Results: In Exp. 1, ingestion of resistant maltodextrin and hydrogenated resistant maltodextrin dose-dependently enhanced apparent absorption rates of Ca, Mg, Fe and Zn, and increased cecal fermentation with cecal expansion. In Exp. 2, the absorption rates of Ca and Mg were significantly enhanced by ingestion of hydrogenated resistant maltodextrin in Sham group but not in CX group. The promotion of Fe and Zn absorption was not affected by cecectomy. Conclusion: Ingestion of resistant maltodextrin and hydrogenated resistant maltodextrin increased apparent Ca and Mg absorptions dependent on cecal fermentation, while other mechanisms may also be involved in promotion of apparent Fe and Zn absorption by resistant maltodextrin.

As the physiological functions of soluble dietary fibre, the favourable efficacy, such as attenuating the absorption of saccharides or lipids, is expected. Resistant maltodextrin, a soluble dietary fibre, was investigated and found that it delays the glucose absorption and attenuates the postprandial rise in the blood glucose levels, however, the efficacy of resistant maltodextrin on lipid metabolism is not yet reported. We conducted an animal experiment and a human experiment to investigate the effect of resistant maltodextrin on postprandial blood triacylglycerol elevation. 1. Rats were fed corn oil with or without resistant maltodextrin and the postprandial changes in triacylglycerol were examined. 2. We then conducted a dietary loading experiment on 13 healthy adult male and female subjects using a meal containing approximately 50 g fat. A beverage not containing resistant maltodextrin was used as a placebo; subjects consumed the loading meal and a beverage containing either 5 g or 10 g resistant maltodextrin; blood was periodically collected to see the changes in serum constituents. 1. The corn oil administration experiment using rats showed that resistant maltodextrin dose-dependently suppressed elevation of blood triacylglycerol levels after corn oil administration. 2. The dietary loading experiment on 13 healthy subjects with 5 or 10 g of resistant maltodextrin showed that; in each administration group, resistant maltodextrin significantly suppressed postprandial elevation of blood triacylglycerol, RLP-cholesterol and insulin. These results indicate that resistant maltodextrin ingested with fatty meals suppresses the postprandial elevation of blood triacylglycerol levels.