Dietary Fiber and Its Potential Role in Obesity: A Focus on Modulating the Gut Microbiota.

Dietary fiber is a carbohydrate polymer with ten or more monomeric units that are resistant to digestion by human digestive enzymes, and it has gained widespread attention due to its significant role in health improvement through regulating gut microbiota. In this review, we summarized the interaction between dietary fiber, gut microbiota, and obesity, and the beneficial effects of dietary fiber on obesity through the modulation of microbiota, such as modifying selective microbial composition, producing starch-degrading enzymes, improving gut barrier function, reducing the inflammatory response, reducing trimethylamine N-oxide, and promoting the production of gut microbial metabolites (e.g., short chain fatty acids, bile acids, ferulic acid, and succinate). In addition, factors affecting the gut microbiota composition and metabolites by dietary fiber (length of the chain, monosaccharide composition, glycosidic bonds) were also concluded. Moreover, strategies for enhancing the biological activity of dietary fiber (fermentation technology, ultrasonic modification, nanotechnology, and microfluidization) were subsequently discussed. This review may provide clues for deeply exploring the structure-activity relationship between dietary fiber and antiobesity properties by targeting specific gut microbiota.

Effect of Lactobacillus with Feruloyl Esterase-Producing Ability on Dextran Sodium Sulfate-Induced Ulcerative Colitis in Mice.

Ulcerative colitis (UC) is becoming an increasingly serious health problem. This study aimed to investigate the effect of a newly isolated Lactobacillus species that produces feruloyl esterase (FAEb) on dextran sodium sulfate (DSS)-induced UC in mice. In this study, FAEb supplementation slowed body weight loss and mitigated colon length shortening, the severity of fecal occult blood, and increases in the disease activity index (DAI) in UC model mice. FAEb supplementation was also shown to reduce the expression of proinflammatory factors, increase the antioxidant capacity, improve the production of beneficial short-chain fatty acids (SCFAs), upregulate the expression of tight junction proteins, reduce the histopathological scores, and reduce mucous barrier damage in the gut. Furthermore, FAEb supplementation was shown to inhibit inflammatory NF-κB signaling pathway activity, increase the abundance of beneficial bacteria, and regulate the balance of microbiota in the gut. These results suggest that FAEb may serve as a potential probiotic to prevent and treat UC.

Broccoli microgreens have hypoglycemic effect by improving blood lipid and inflammatory factors while modulating gut microbiota in mice with type 2 diabetes.

This study aims to explore the hypoglycemic effect of lyophilized broccoli microgreens on type 2 diabetes (T2D) in mice. The experiment lasted 18 weeks, including 1 week of adaptation (normal diet) and 17-week experimental period (high-fat diet). After ingestion of broccoli microgreens, the body weight and glucose homeostasis were improved. Meanwhile, the blood lipid status, antioxidant indexes, and inflammatory factors level were improved. Moreover, the insulin resistance and the pathological changes in mice organs were reversed. In addition, the composition of gut microbiota and the production of propionic acid in intestinal content were improved. Our experiment proved that broccoli microgreens have the ability to regulate T2D and improve symptoms of mice T2D induced by high-fat diet and streptozotocin (STZ). PRACTICAL APPLICATIONS: For years, the functionality of broccoli microgreens has attracted much attention. This article will prove the therapeutic effect of broccoli microgreens on T2D and explain its principle of action in the management of T2D.

The protective effects of sulforaphane on high-fat diet-induced metabolic associated fatty liver disease in mice via mediating the FXR/LXRα pathway.

Metabolic-associated fatty liver disease (MAFLD) is becoming the key factor in causing chronic liver disease all over the world. Sulforaphane (SFN) has been proven to be effective in alleviating many metabolic diseases, such as obesity and type 2 diabetes. In this study, C57BL/6 mice were fed a high-fat diet for 12 weeks to induce MAFLD and given SFN (10 mg per kg bw) daily. Our results showed that SFN not only improved the excessive accumulation of fat in the liver cells but also ameliorated liver and serum inflammatory and antioxidant levels. In addition, SFN can regulate bile-acid metabolism and fatty-acid synthesis by affecting their farnesoid X receptor (FXR)/liver X receptor alpha (LXRα) signaling pathway, ultimately alleviating MAFLD. Our study provides a theoretical basis for the mechanism by which SFN alleviates hepatic steatosis.

Effects of L-arabinose by hypoglycemic and modulating gut microbiome in a high-fat diet- and streptozotocin-induced mouse model of type 2 diabetes mellitus.

L-arabinose is a good and healthy food additive. This study was conducted to investigate the effect of L-arabinose in a mouse model of type 2 diabetes mellitus (T2DM) induced by exposure to a high-fat diet (HFD) and streptozotocin (STZ). The model mice received L-arabinose at 20 and 60 mg (kg body weight [bw])-1 d-1 , metformin at 300 mg (kg bw)-1 d-1 (positive control) or sterile water (control) via oral gavage. Compared with the model group, mice treated with L-arabinose exhibited attenuated symptoms of diabetes mellitus, including a slower rate of body weight loss, increased homeostasis model assessment of ß-cell function index levels, decreased blood glucose, alleviation of steatosis, and repair of pancreatic islet cells. L-arabinose also exerted an anti-inflammatory effect and partially mitigated dyslipidemia. A 16S-rRNA sequence analysis of the gut microbiota revealed that at the phylum level, treatment with L-arabinose significantly reduced the ratio of Firmicutes to Bacteroidetes due to a decreased relative abundance of Firmicutes; at the genus level, it reversed the increase in the relative abundance of Allobaculum and the decrease abundance of Oscillospira caused by exposure to an HFD and STZ. And the model mice received L-arabinose at 20 mg (kg bw)-1 d-1 had a better effect on improving T2DM than the high-dose group supplemented L-arabinose at 60 mg (kg bw)-1 d-1 . These results strongly suggest L-arabinose as an excellent candidate supplement to prevent or treat T2DM. PRACTICAL APPLICATIONS: L-arabinose, xylitol and sucralose are well-known substitutes for sucrose. L-arabinose has been reported to have beneficial effects on hyperglycemia, glycemic index, and fat accumulation. In this study, we found that low-dose (20 mg (kg bw)-1 d-1 ) supplementation of L-arabinose significantly improved glucose intolerance and gut microbiota incoordination in T2DM caused by HFD and STZ.