title: Chronic coffee consumption in the diet-induced obese rat: impact on gut microbiota and serum metabolomics.
abstract: Epidemiological data confirms a strong negative association between regular coffee consumption and the prevalence of type 2 diabetes. Coffee is initially absorbed in the stomach and small intestine but is further fermented in the colon by gut microbiota. The bioavailability, production and biological activity of coffee polyphenols is modulated, in part, by gut microbiota. The purpose of this study was to determine if chronic coffee consumption could mitigate negative gut microbiota and metabolomic profile changes induced by a high-fat diet. Male Sprague-Dawley rats were randomized to chow (12% kcal fat) or high-fat (60% kcal fat) diet. Each group was further divided into water or caffeinated coffee for 10 weeks. Coffee consumption in high-fat-fed rats was associated with decreased body weight, adiposity, liver triglycerides and energy intake. Despite a more favorable body composition, rats displayed profound systemic insulin resistance, likely due to caffeine. Coffee consumption attenuated the increase in Firmicutes (F)-to-Bacteroidetes (B) ratio and Clostridium Cluster XI normally associated with high-fat feeding but also resulted in augmented levels of Enterobacteria. In the serum metabolome, coffee had a distinct impact, increasing levels of aromatic and circulating short-chain fatty acids while lowering levels of branched-chain amino acids. In summary, coffee consumption is able to alter gut microbiota in high-fat-fed rats although the role of these changes in reducing diabetes risk is unclear given the increased insulin resistance observed with coffee in this study.
authors.affiliation: Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada. Electronic address: t.cowan@queensu.ca.
authors.forename: Theresa E
authors.initials: TE
authors.lastname: Cowan
authors.affiliation: Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada; Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB, Canada.
authors.forename: Marie S A
authors.initials: MS
authors.lastname: Palmnäs
authors.affiliation: Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada.
authors.forename: Jaeun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Bomhof
authors.affiliation: Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada.
authors.forename: Kendra L
authors.initials: KL
authors.lastname: Ardell
authors.affiliation: Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada; Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB, Canada.
authors.forename: Raylene A
authors.initials: RA
authors.lastname: Reimer
authors.affiliation: Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada; Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB, Canada.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Vogel
authors.affiliation: Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada; Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB, Canada.
authors.forename: Jane
authors.initials: J
authors.lastname: Shearer
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology; D003069:Coffee; D059305:Diet, High-Fat / Q000009:adverse effects*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D007333:Insulin Resistance; D055432:Metabolomics; D009765:Obesity / Q000139:chemically induced / Q000178:diet therapy* / Q000378:metabolism; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D003069:Coffee; D002110:Caffeine
keywords: Caffeine; Coffee; Glucose; Gut microbiota; Insulin resistance