Not all dietary fibers alleviate type 2 diabetes

Abstract Background High intake of dietary fiber was found to be inversely associated with type 2 diabetes (T2D), whereas the difference among different dietary fibers on T2D is still not clear.Results Here we investigated the effects of 9 types of dietary fiber on type 2 diabetic rats. we found supplementation with β-glucan, arabinogalactan, guar gum, apple pectin, glucomannan, arabinoxylan (especially β-glucan and arabinogalactan treatment) significantly reduced the fasting blood glucose, whereas carrageenan, xylan and xanthan gum had no effect on glycemic control in rats with T2D. Fibers with hypoglycemic effects associated with the increased butyric acid level and abundance of beneficial bacteria (Anaeroplasma, Parabacteroides and some butyric acid-producing bacteria), as well as improved host metabolism by decreasing 12α-hydroxylated bile acids, acylcarnitines and amino acids (leucine, phenylalanine, citrulline, and etc.). It was also found that only β-glucan can attenuate insulin resistance in T2D via down-regulation of Prevotella copri mediated branched chain amino acids biosynthesis.Conclusions not all dietary fibers were able to improve T2D, which mainly relied on the improvement of composition and functions of gut microbiota.