Scope High‐fat diet (HFD) intake induces gut dysbiosis, inflammation in the peripheral tissues, and a reduction in immunoglobulin A (IgA) coating of gut bacteria, which is related to HFD‐induced insulin resistance (IR). This study evaluates the effect of cyclic nigerosylnigerose (CNN), a dietary fiber that prevents gut inflammation and promotes IgA coating of gut bacteria, on the above‐mentioned HFD‐induced disorders. Methods and results Balb/c mice are fed an HFD and administered CNN for 20 weeks. CNN administration reduces mesenteric adipose tissue weight, colonic tumor necrosis factor α (TNFα) mRNA expression, and serum endotoxin levels and ameliorates HFD‐induced abnormal glucose metabolism. Additionally, CNN administration promotes gut bacteria‐specific IgA secretion and alters IgA reactivity to gut bacteria. The alterations of IgA reactivity to specific bacteria such as Erysipelatoclostridium, Escherichia, Faecalibaculum, Lachnospiraceae genera, and Stenotrophomonas are correlated with mesenteric adipose tissue weight, colonic TNFα mRNA expression, serum endotoxin levels, and a homeostasis model assessment for IR. Conclusion CNN‐induced alterations in IgA reactivity to gut bacteria may be related to the suppression of HFD‐induced fat deposition, colonic inflammation, endotoxemia, and IR. These observations indicate that dietary fiber that modulates IgA reactivity to gut bacteria may be useful in preventing HFD‐induced disorders.

Mol. Nutr. Food Res. 2023, 67, 202200389 DOI: https://doi.org/10.1002/mnfr.202200389 Oral administration of cyclic nigerosylnigerose (CNN), a dietary fiber, ameliorates abnormal glucose metabolism, fat deposition, and colonic inflammation in mice with high‐fat diet‐induced obesity. Impressively, the CNN‐induced effects are accompanied by an alteration of gut immunoglobulin A (IgA) reactivity to commensal gut bacteria. This is reported by Takeshi Tsuruta and co‐workers in article number 2200389.