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- Cowan, Theresa, et al.
(author)
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Chronic coffee consumption in the diet-induced obese rat: impact on gut microbiota and serum metabolomics
- 2014
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In: Journal of Nutritional Biochemistry. - : Elsevier BV. - 0955-2863 .- 1873-4847. ; 25:4, s. 489-495
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Journal article (peer-reviewed)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.
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| 2. |
- Palmnäs, Marie, 1988, et al.
(author)
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Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat
- 2014
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 9:10
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Journal article (peer-reviewed)abstract
- Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat) or high fat (HF, 60% kcal fat) and further into ad libitum water control (W) or low-dose aspartame (A, 5–7 mg/kg/d in drinking water) treatments for 8 week (n = 10–12 animals/treatment). Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (P<0.05). Within HF, aspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.
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