Dietary Fiber in Bilberry Ameliorates Pre-Obesity Events in Rats by Regulating Lipid Depot, Cecal Short-Chain Fatty Acid Formation and Microbiota Composition
Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden
Department of Biochemistry and Molecular Medicine, University of California at Davis, Sacramento, CA 95817, USA
Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, 75236 Uppsala, Sweden
Department of Food Technology, Engineering and Nutrition, Lund University, 22100 Lund, Sweden
Authors to whom correspondence should be addressed.
These authors contributed equally to this paper.
Nutrients 2019, 11(6), 1350; https://doi.org/10.3390/nu11061350
Received: 8 May 2019 / Revised: 5 June 2019 / Accepted: 11 June 2019 / Published: 15 June 2019
(This article belongs to the Special Issue Dietary Fiber and Human Health)
Obesity is linked to non-alcoholic fatty liver disease and risk factors associated to metabolic syndrome. Bilberry (Vaccinium myrtillus) that contains easily fermentable fiber may strengthen the intestinal barrier function, attenuate inflammation and modulate gut microbiota composition, thereby prevent obesity development. In the current study, liver lipid metabolism, fat depot, cecal and serum short-chain fatty acids (SCFAs) and gut microbiome were evaluated in rats fed bilberries in a high-fat (HFD + BB) or low-fat (LFD + BB) setting for 8 weeks and compared with diets containing equal amount of fiber resistant to fermentation (cellulose, HFD and LFD). HFD fed rats did not obtain an obese phenotype but underwent pre-obesity events including increased liver index, lipid accumulation and increased serum cholesterol levels. This was linked to shifts of cecal bacterial community and reduction of major SCFAs. Bilberry inclusion improved liver metabolism and serum lipid levels. Bilberry inclusion under either LFD or HFD, maintained microbiota homeostasis, stimulated interscapular-brown adipose tissue depot associated with increased mRNA expression of uncoupling protein-1; enhanced SCFAs in the cecum and circulation; and promoted butyric acid and butyrate-producing bacteria. These findings suggest that bilberry may serve as a preventative dietary measure to optimize microbiome and associated lipid metabolism during or prior to HFD.