A comparison between partially peeled hulless barley and whole grain hulless barley: beneficial effects on the regulation of serum glucose and the gut microbiota in high-fat diet-induced obese mice.

Though the hypoglycemic effect of whole grain hulless barley (Hordeum vulgare L.) has been documented, whether glucose metabolism would be improved by hulless barley with moderate peeling is still unclear. The purpose of this study was to compare the differences in glucose metabolism and gut microbiota between partially (10%) peeled hulless barley (PHB) and whole grain hulless barley (WHB) intervention in obese mice induced by a high-fat diet. The results showed that both PHB and WHB interventions significantly improved the impaired glucose tolerance, fat accumulation in fat and liver tissues, and the impaired intestinal barrier in mice. The dysbiosis of gut microbiota was improved and the relative abundance of some beneficial bacteria such as genera Lactobacillus, Bifidobacterium, Ileibacterium, and norank_f__Mutibaculaceae was increased by both, PHB and WHB, interventions. Spearman correlation analysis revealed that the abundance of Bifidobacterium was negatively correlated with the area under the blood glucose curve. In conclusion, our results provide evidence that hulless barley improved the gut microbiota and impaired glucose tolerance in mice, and also showed that there was little loss of hypoglycemic effect even when hulless barley was moderately peeled.

Corrigendum: Effect of Different Processing Methods on the Millet Polyphenols and Their Anti-diabetic Potential.

[This corrects the article DOI: 10.3389/fnut.2022.780499.].

Effect of Different Processing Methods on the Millet Polyphenols and Their Anti-diabetic Potential.

Interest in polyphenols has grown due to their beneficial effect on diabetes attenuation. Millets are ancient crops that are rich in polyphenols and used for both food and feed. They are grown worldwide and are adapted to production under dry, hot conditions. The polyphenols found in millets have anti-diabetic properties. However, millet is usually consumed after being processed by heating, germination, fermentation, and other processing methods, which may alter polyphenol content and thus affect their anti-diabetic potential. This mini-review profiles the effects of different processing methods on millet polyphenols and how changes in millet polyphenols affect the hypoglycemic effect of millet. Future studies are needed to compare the anti-diabetes potential of millet polyphenols before and after processing and to explore ways to minimize polyphenol losses and thus maintain their hypoglycemic effect in final products.

Beneficial Effects of Partly Milled Highland Barley on the Prevention of High-Fat Diet-Induced Glycometabolic Disorder and the Modulation of Gut Microbiota in Mice.

The nutritional functions of highland barley (HB) are superior to those of regular cereals and have attracted increasing attention in recent years. The objective of this study was to investigate whether partly milled highland barley (PHB) can regulate the serum glucose and lipid disorders of mice fed a high-fat diet (HFD) and to further explore their potential gut microbiota modulatory effect. Our results showed that PHB supplementation significantly reduced fasting blood glucose (FBG) and improved oral glucose tolerance. Histological observations confirmed the ability of PHB to alleviate liver and intestine damage. Furthermore, the results of 16S amplicon sequencing revealed that PHB prevented a HFD-induced gut microbiota dysbiosis, enriching some beneficial bacteria, such as Lactobacillus, Bifidobacterium, and Ileibacterium, and reducing several HFD-dependent taxa (norank_f_Desulfovibrionaceae, Blautia, norank_f_Lachnospiraceae, unclassified_f_Lachnospiraceae, and Colidextribacter). In addition, the increase of Lactobacillus and Bifidobacterium presence has a slightly dose-dependent relationship with the amount of the added PHB. Spearman correlation analysis revealed that Lactobacillus and Bifidobacterium were negatively correlated with the blood glucose level of the oral glucose tolerance test. Overall, our results provide important information about the processing of highland barley to retain its hypoglycemic effect and improve its acceptability and biosafety.

Heat-Treated Adzuki Bean Protein Hydrolysates Reduce Obesity in Mice Fed a High-Fat Diet via Remodeling Gut Microbiota and Improving Metabolic Function.

SCOPE: Heat-treated adzuki bean protein hydrolysates (APH) reduce cholesterol in vitro. However, it is unclear if APH have anti-obesity effects in vivo and, if so, the relationship between the effects and the improvement of gut microbiota composition and metabolic function. METHODS AND RESULTS: Four groups of mice are fed either a normal control diet (NCD) or a high-fat diet (HFD) with or without APH for 12 weeks. In HFD-fed mice, APH supplementation significantly alleviate fat accumulation, dyslipidemia, insulin resistance, hepatic steatosis, and inflammation. In addition, APH supplementation regulate gut microbiota composition, reduce the abundance of harmful bacteria (Clostridium_sensu_stricto_1, Romboutsia, Blautia, Mucispirillum, Bilophila, and Peptococcus), enrich Lactobacillus and SCFA-producing bacteria (Lactobacillaceae, Eisenbergiella, Alistipes, Parabacteroides, Tannerellaceae, Eubacterium_nodatum_group, Acetatifactor, Rikenellaceae, and Odoribacter), and increase fecal SCFAs concentration. Importantly, APH supplementation significantly regulate the levels of serum metabolites, especially Lactobacillus-derived metabolites and tryptophan derivatives, which help to alleviate obesity and its complications. CONCLUSION: APH improve gut microbiota composition and metabolic function in mice and may help to prevent and treat obesity and related complications.