A critical review on inflammatory bowel diseases risk factors, dietary nutrients regulation and protective pathways based on gut microbiota during recent 5 years.

The treatment of inflammatory bowel diseases (IBDs) has become a worldwide problem. Intestinal flora plays an important role in the development and progression of IBDs. Various risk factors (psychology, living habits, dietary patterns, environment) influence the structure and composition of the gut microbiota and contribute to the susceptibility to IBDs. This review aims to provide a comprehensive overview on risk factors regulating intestinal microenvironment which was contributed to IBDs. Five protective pathways related to intestinal flora were also discussed. We hope to provide systemic and comprehensive insights of IBDs treatment and to offer theoretical guidance for personalized patients with precision nutrition.

Proanthocyanidins and ß-Glucan Synergistically Regulate Intestinal Inflammation in Dextran Sulfate Sodium-Induced Colitis Mice.

Proanthocyanidins (PA) have been proven to have an anti-inflammation effect in multiple models by regulating oxidative stress. ß-glucan (BG) could alleviate colitis from the perspectives of intestinal permeability and gut microbiota. In the present study, the synergistic anti-inflammatory function of PA and BG was explored from multiple aspects including immune response, intestinal barrier, gut microbiota, and differential metabolites. The results showed that the supplementation of PA and BG improved the colitis symptoms including atrophy of the colon, body weight loss, and organ index increase. Additionally, inflammatory cytokine levels and oxidative stress status were significantly regulated with the intake of PA and BG. Moreover, PA and BG intervention improved intestinal permeability and promoted the expression of barrier proteins. The microbiome and metabolic profile of cecal contents showed that PA and BG supplementation increased the abundance of anti-inflammatory bacteria and decreased the abundance of pro-inflammatory bacteria. Furthermore, some beneficial metabolites involved in amino acid metabolism, carbohydrate metabolism, and biosynthesis of other secondary metabolite pathways were increased. Overall, these findings have demonstrated the regulation of the inflammatory response and remodel of metabolite profiles by PA and BG complexes, indicating that it may serve as a new strategy for inflammatory bowel disease treatment in the future.

Effects of Konjac Glucomannan on Weight Management and Liver Health: Insights from Liver Lipidomics in Obese and Nonobese Mice.

Konjac glucomannan (KGM) is a water-soluble dietary fiber and is used for weight management. However, there is a lack of research on KGM for weight management in nonobese groups and the effects of high-dose KGM supplementation on liver function. This study investigated the metabolic responses to KGM intervention in obese and nonobese mice and explored the underlying mechanisms based on lipidomics. The findings demonstrated that KGM supplementation decreased body weight and mitigated lipid metabolism disorders at the mRNA and protein levels in obese mice. In contrast, no significant impact on these parameters was observed in nonobese mice. Interestingly, KGM had a more significant impact on remodeling hepatic lipid composition in obese mice compared to nonobese mice, leading to reducing harmful lipids and increasing beneficial lipids. However, high-dose KGM increased the risk of hepatocyte bile acid toxicity in obese mice and did not promote liver antioxidant status in nonobese mice. In summary, this study identified distinct metabolic responses to KGM intervention between obese and nonobese mice, providing insights for weight management using KGM.

Effects of konjac glucomannan intake patterns on glucose and lipid metabolism of obese mice induced by a high fat diet.

Konjac glucomannan (KGM) is a dietary fiber supplement that exhibits multiple biological activities, including weight control as well as regulation of glucose and lipid metabolism. Currently, KGM intake patterns in practical applications include KGM sol, thermal irreversible gel, and frozen thermal irreversible gel. In this study, four intake patterns of KGM, namely KGM sol (KS), deacetylated KGM (DK), KGM gel (KG), and frozen KGM gel (FKG), were used as materials to explore the effects of different KGM intake patterns on glucose and lipid metabolism and intestinal flora in obese mice induced by a high fat diet under the same dose. The results showed that any type of KGM intake could reduce body weight, fat mass, lipid levels, and insulin resistance in obese mice, and alleviate liver damage and inflammation caused by obesity. However, KS has the most significant effect on controlling blood glucose and blood lipid in obese mice. Additionally, it was found that KS, DK, KG and FKG can increase the α-diversity of intestinal microflora in high-fat mice and improve the microflora disorder in high-fat mice. Finally, KS may increase the levels of fasting appetite hormones GLP-1 and PYY in mice, up-regulate the expression of LDLR, GCK and G-6-pase mRNA, and increase the production of short-chain fatty acids (SCFAs) in the intestinal flora of mice, thus regulating glucose and lipid metabolism. This study systematically investigated the effects of different intake forms of KGM on metabolism and intestinal flora in obese mice, which is of great significance for further understanding the role of KGM in the prevention and treatment of obesity-related metabolic diseases and for developing targeted dietary interventions.

Effects of KGM and Degradation Products on Appetite Regulation and Energy Expenditure in High-Fat-Diet Mice via the Adipocyte-Hypothalamus Axis.

Konjac glucomannan (KGM), high-viscosity dietary fiber, is utilized in weight management. Previous investigations on the appetite-suppressing effects of KGM have centered on intestinal responses to nutrients and gastric emptying rates, with less focus on downstream hypothalamic neurons of satiety hormones. In our studies, the molecular mechanisms through which KGM and its degradation products influence energy homeostasis via the adipocyte-hypothalamic axis have been examined. It was found that high-viscosity KGM more effectively stimulates enteroendocrine cells to release glucagon-like peptide-1 (GLP-1) and reduces ghrelin production, thereby activating hypothalamic neurons and moderating short-term satiety. Conversely, low-viscosity DKGM has been shown to exhibit stronger anti-inflammatory properties in the hypothalamus, enhancing hormone sensitivity and lowering the satiety threshold. Notably, both KGM and DKGM significantly reduced leptin signaling and fatty acid signaling in adipose tissue and activated brown adipose tissue thermogenesis to suppress pro-opiomelanocortin (POMC) expression and activate agouti-related protein (AgRP) expression, thereby reducing food intake and increasing energy expenditure. Additionally, high-viscosity KGM has been found to activate the adipocyte-hypothalamus axis more effectively than DKGM, thereby promoting greater daily energy expenditure. These findings provide novel insights into the adipocyte-hypothalamic axis for KGM to suppress appetite and reduce weight.

Regulation of glycose and lipid metabolism and application based on the colloidal nutrition science properties of konjac glucomannan: A comprehensive review.

The physicochemical properties of dietary fiber in the gastrointestinal tract, such as hydration properties, adsorption properties, rheological properties, have an important influence on the physiological process of host digestion and absorption, leading to the differences in satiety and glucose and lipid metabolisms. Based on the diversified physicochemical properties of konjac glucomannan (KGM), it is meaningful to review the relationship of structural characteristics, physicochemical properties and glycose and lipid metabolism. Firstly, this paper bypassed the category of intestinal microbes, and explained the potential of dietary fiber in regulating glucose and lipid metabolism during nutrient digestion and absorption from the perspective of colloidal nutrition. Secondly, the modification methods of KGM to regulate its physicochemical properties were discussed and the relationship between KGM's molecular structure types and glycose and lipid metabolism were summarized. Finally, based on the characteristics of KGM, the application of KGM in the main material and ingredients of fat reduction food was reviewed. We hope this work could provide theoretical basis for the study of dietary fiber colloid nutrition science.

Selenium-containing soybean peptides ameliorate intestinal inflammation and modulate gut microbiota dysbacteriosis in DSS-induced ulcerative colitis mice.

The purpose of this study was to explore the protective effects of selenium containing soybean peptides (SePPs) on inflammatory bowel disease in colitis mice. During the experimental period, the mice were administered with SePPs for 14 days, and then treated with drinking water containing 2.5% dextran sodium sulfate (DSS) for 9 days, while the intervention of SePPs was continued. The results showed that low-dose SePPs (15 µg Se per kg per d bw) could effectively alleviate DSS-induced inflammatory bowel disease through the improvement of the antioxidant levels, reduction of inflammatory factor levels, and increase of tight junction protein expression of ZO-1 and occludin in the colon, thus improving the structure of the colon and strengthening the barrier function of the small intestine. Additionally, SePPs were found to significantly improve the production of short chain fatty acids (P < 0.05). Moreover, SePPs could improve intestinal microbiota diversity, significantly increasing the Firmicutes/Bacteroidetes ratio and the abundance of some beneficial genera, such as Lachnospiraceae_NK4A136_group and Lactobacillus (P < 0.05). Though high-dose SePPs (30 µg Se per kg per d bw) could improve DSS induced bowel disease, the effect was worse than that in the low-dose SePP group. These findings provide new insights into Se-containing peptides as a functional food against inflammatory bowel disease and dietary selenium supplementation.

Konjac glucomannan-assisted curcumin alleviated dextran sulfate sodium-induced mice colitis via regulating immune response and maintaining intestinal barrier integrity.

Curcumin has been proven to be an effective strategy for reducing inflammatory responses. However, low bioavailability and instability at the physiological pH have limited its anti-inflammatory activity in ulcerative colitis patients. In the present study, a complex of curcumin and konjac glucomannan (KGM) effectively inhibited intestinal inflammation and this effect was associated with KGM degradation degrees. Results demonstrated that treatment with the complex markedly mitigated colitis symptoms and decreased inflammatory cytokines levels, especially in the complex treatment groups with K110 (KGM treated in 110 °C) and konjac oligosaccharides (KOSs). Furthermore, increasing the KOS content in KOC (the complex of curcumin and KOS) promoted the gene expressions of the intestinal barrier and inhibited the gene expressions of inflammatory cytokines, as well as improved gut microbiota dysregulation. Overall, our studies suggest that the complex of curcumin and KGM exerts effective anti-inflammatory effects by regulating the intestinal immune response and modulating microbiota diversity and composition.

Evaluation of the effect of prebiotic sesame candies on loperamide-induced constipation in mice.

Constipation is one of the most common gastrointestinal tract symptoms. In this study, prebiotic sesame sugar (PSC) was prepared from isomalto-oligosaccharide, konjac glucomannan and sesame, and the relieving effect of PSC on constipation induced by loperamide was explored. The results showed that PSC treatment profoundly improved the defecation function and boosted intestinal motility. Moreover, PSC repaired gastrointestinal tissue injury and inflammation induced by constipation, which confirmed the effectiveness of PSC intervention in the treatment of constipation. The mechanism of PSC improving constipation might be that PSC improved the imbalance of gastrointestinal neurotransmitters and increased the content of short-chain fatty acids in feces. In conclusion, PSC dietotherapy could effectively alleviate the symptoms and lay a theoretical foundation for the development of an anti-constipation diet.

Konjac oligosaccharides attenuate DSS-induced ulcerative colitis in mice: mechanistic insights.

This study aims to explore the protective effect of konjac oligosaccharides (KOS) on inflammatory bowel disease in colitis mice. During the experimental period, mice were administered 200 mg kg-1 or 600 mg kg-1 KOS, 200 mg kg-1 sulfasalazine and a combination of KOS and sulfasalazine for 14 days. The mice were then treated with drinking water containing 2.5% DSS for 9 days, while the intervention of KOS and sulfasalazine continued. At the end of the experiment, the phenotype, pathological lesion of the colon, parameters of cytokines and gut microbiota were evaluated. The results showed that mice treated with KOS exhibited alleviated pathological lesion of the colon tissue and significantly increased expression of tight junction proteins (p < 0.05). The level of inflammatory cytokines in the colon tissue of the colitis mice tended to be normal. Moreover, the analysis of the gut microbiota revealed that the structures and composition of the intestinal microorganisms were also regulated by KOS treatment. The possible internal mechanism is that KOS down-regulates the abundance of pro-inflammatory bacteria (Proteobacteria, Campilobacterota and Clostridiaceae) and up-regulates the abundance of anti-inflammatory bacteria (Bifidobacteriaceae and Akkermansiaceae). These findings provide new insights into dietary management for patients with inflammatory bowel disease.