Cocoa diet modulates gut microbiota composition and improves intestinal health in Zucker diabetic rats

Food Res Int. 2020 Jun:132:109058. doi: 10.1016/j.foodres.2020.109058. Epub 2020 Feb 1.

Abstract

Cocoa supplementation improves glucose metabolism in Zucker diabetic fatty (ZDF) rats via multiple mechanisms. Furthermore, cocoa rich-diets modify the intestinal microbiota composition both in humans and rats in healthy conditions. Accordingly, we hypothesized that cocoa could interact with the gut microbiota (GM) in ZDF rats, contributing to their antidiabetic effects. Therefore, here we investigate the effect of cocoa intake on gut health and GM in ZDF diabetic rats. Male ZDF rats were fed with standard (ZDF-C) or 10% cocoa-rich diet (ZDF-Co) during 10 weeks. Zucker Lean animals (ZL) received the standard diet. Colon tissues were obtained to determine the barrier integrity and the inflammatory status of the intestine and faeces were analysed for microbial composition, short-chain fatty acids (SCFA) and lactate levels. We found that cocoa supplementation up-regulated the levels of the tight junction protein Zonula occludens-1 (ZO-1) and the mucin glycoprotein and reduced the expression of pro-inflammatory cytokines such as tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein 1 (MCP-1) in the colon of ZDF diabetic animals. Additionally, cocoa modulated the microbial composition of the ZDF rats to values similar to those of the lean group. Importantly, cocoa treatment increased the relative abundance of acetate-producing bacteria such as Blautia and prevented the increase in the relative amount of lactate-producing bacteria (mainly Enterococcus and Lactobacillus genera) in ZDF diabetic animals. Accordingly, the total levels of SCFA (mainly acetate) increased significantly in the faeces of ZDF-Co diabetic rats. Finally, modified GM was closely associated with improved biochemical parameters related to glucose homeostasis and intestinal integrity and inflammation. These findings demonstrate for the first time that cocoa intake modifies intestinal bacteria composition towards a healthier microbial profile in diabetic animals and suggest that these changes could be associated with the improved glucose homeostasis and gut health induced by cocoa in ZDF diabetic rats.

Keywords: Cocoa flavanols; Diabetes type 2; Glucose homeostasis; Gut barrier; Gut inflammation; Gut microbiota.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacteria / classification
  • Blood Glucose
  • Cacao*
  • Chemokine CCL2
  • Colon / microbiology
  • Colon / pathology
  • Diabetes Mellitus, Experimental / diet therapy*
  • Diet*
  • Fatty Acids, Volatile
  • Gastrointestinal Microbiome / drug effects*
  • Glucose Tolerance Test
  • Homeostasis / drug effects
  • Hypoglycemic Agents / pharmacology
  • Interleukin-6
  • Male
  • Rats
  • Rats, Zucker
  • Tumor Necrosis Factor-alpha
  • Zonula Occludens-1 Protein / metabolism

Substances

  • Blood Glucose
  • Chemokine CCL2
  • Fatty Acids, Volatile
  • Hypoglycemic Agents
  • Interleukin-6
  • Tumor Necrosis Factor-alpha
  • Zonula Occludens-1 Protein