Refined highland barley ameliorates obesity-associated insulin resistance in high-fat diet-fed mice by targeting the gut microbiota and liver transcriptomics.

Purpose: It is generally believed that refined grains lack nutritional value compared to whole grains. The objective of this study was to investigate whether refined highland barley (RHB) holds the potential to combat obesity-associated insulin resistance.

Methods: Thirty-two male 6-week-old C57BL/6J mice were randomly divided into four groups fed with a normal chow diet, a high-fat diet (HFD), a 30% RHB supplemented HFD diet, and a 30% whole-grain highland barley (WGHB) supplemented HFD diet. We examined the anti-obesity and anti-insulin resistance effects of RHB and compared them with WGHB in mice.

Results: RHB intervention effectively improved obesity and insulin resistance, enhanced the intestinal mucosal barrier, and reduced inflammation. Moreover, it promoted the abundance of beneficial gut bacteria such as Akkermansia, Bifidobacterium, Lachnospiraceae_NK4A136_group, Lachnospiraceae_UCG-001, Alloprevotella, and increased the production of short-chain fatty acids (SCFAs) in faeces. Additionally, RHB intervention modulated liver gene transcription, downregulating inflammatory genes like IRF3/7, STAT1/2, NLRP3, and TLR2.

Conclusions: RHB could effectively alleviate obesity-related insulin resistance by targeting gut microbiota and liver transcriptomics, and its beneficial impacts are comparable to those of WGHB.