Raspberry intake reduces skeletal muscle lipid accumulation and improves insulin sensitivity in mice fed high fat diet

Abstract

IntroductionPolyphenolics promote adipose tissue browning and increase lipid oxidation, but their roles in skeletal muscle intracellular lipid accumulation and insulin resistance is unclear. Raspberry contains rich polyphenolic compounds.ObjectiveTo test the protective role of dietary raspberry on lipid accumulation and insulin sensitivity in skeletal muscle of mice fed a high fat diet (HFD).MethodsWild‐type male mice were randomly separated into 4 groups and fed with a control diet (CON) or a high fat diet (HFD, 60% energy as fat mimicking the common high energy, high fat diet in western societies) supplemented with 0 or 5% freeze dried raspberry (RAS) for 12 weeks.ResultsThere was insulin resistance in mice fed with HFD without raspberry, as indicated by increased muscle triglyceride content and attenuated insulin signaling; these adverse changes were ameliorated by raspberry supplementation. In addition, inflammation was detected in the skeletal muscle of HFD mice, as shown by the enhanced expression of tumor necrosis factor α (TNFα), interleukin‐6 (IL‐6) and IL‐1β, as well as the increased phosphorylation of p65, a key mediator of inflammatory nuclear factor (NF)‐κB signaling, which was inhibited due to raspberry consumption.ConclusionRaspberry intake improved insulin resistance and suppressed inflammation in skeletal muscle of mice consuming HFD mimicking the popular western high energy diet.Support or Funding InformationSupported by National Processed Raspberry Council