1.
Role of Probiotics in Non-alcoholic Fatty Liver Disease: Does Gut Microbiota Matter?
Xie, C, Halegoua-DeMarzio, D
Nutrients. 2019;11(11)
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Non-alcoholic fatty liver disease (NAFLD) is characterised by an excessive accumulation of fat in the liver tissue, without excessive alcohol consumption, and appears to be related to metabolic syndrome. It is thought to have a prevalence of 25% globally and there are no pharmacological treatments available. This review discusses the connection between the gut microbiota (GM) and NAFLD. Various mechanisms by which the GM may be involved in the development of NAFLD are discussed. As probiotics and prebiotics can normalise GM and reverse dysbiosis their use may benefit patients with NAFLD. This has been confirmed in animal models. The authors review 26 randomised controlled trials (RCTs) of probiotics and/or prebiotics in the treatment of NAFLD which evaluate biochemical markers, as well as five meta-analyses, and found that overall there is strong evidence that probiotics and/or prebiotics can lower ALT and AST (markers of NAFLD), although results for other biochemical markers were mixed. They also reviewed RCTs assessing NAFLD by imaging and histological means, and again found benefits from probiotic and/or prebiotic supplementation.
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the hepatic consequence of metabolic syndrome, which often also includes obesity, diabetes, and dyslipidemia. The connection between gut microbiota (GM) and NAFLD has attracted significant attention in recent years. Data has shown that GM affects hepatic lipid metabolism and influences the balance between pro/anti-inflammatory effectors in the liver. Although studies reveal the association between GM dysbiosis and NAFLD, decoding the mechanisms of gut dysbiosis resulting in NAFLD remains challenging. The potential pathophysiology that links GM dysbiosis to NAFLD can be summarized as: (1) disrupting the balance between energy harvest and expenditure, (2) promoting hepatic inflammation (impairing intestinal integrity, facilitating endotoxemia, and initiating inflammatory cascades with cytokines releasing), and (3) altered biochemistry metabolism and GM-related metabolites (i.e., bile acid, short-chain fatty acids, aromatic amino acid derivatives, branched-chain amino acids, choline, ethanol). Due to the hypothesis that probiotics/synbiotics could normalize GM and reverse dysbiosis, there have been efforts to investigate the therapeutic effect of probiotics/synbiotics in patients with NAFLD. Recent randomized clinical trials suggest that probiotics/synbiotics could improve transaminases, hepatic steatosis, and reduce hepatic inflammation. Despite these promising results, future studies are necessary to understand the full role GM plays in NAFLD development and progression. Additionally, further data is needed to unravel probiotics/synbiotics efficacy, safety, and sustainability as a novel pharmacologic approaches to NAFLD.
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The Fluid Aspect of the Mediterranean Diet in the Prevention and Management of Cardiovascular Disease and Diabetes: The Role of Polyphenol Content in Moderate Consumption of Wine and Olive Oil.
Ditano-Vázquez, P, Torres-Peña, JD, Galeano-Valle, F, Pérez-Caballero, AI, Demelo-Rodríguez, P, Lopez-Miranda, J, Katsiki, N, Delgado-Lista, J, Alvarez-Sala-Walther, LA
Nutrients. 2019;11(11)
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The Mediterranean diet is considered one of the most studied diets in scientific literature and this review specifically looks at two fluid aspects of the MedDiet; olive oil and red wine. Olive oil is rich in phenolic compounds and red wine in polyphenols and the study looks at their therapeutic effect on cardiovascular disease prevention, particularly on lipids, blood pressure, plaque and glucose metabolism. Known mechanisms of the MedDiet include reduction of inflammatory and oxidative stress markers, and an improvement in lipid profile and insulin sensitivity. Polyphenols are important antioxidants abundant in plant foods including olives and red grapes used in wine (known to be x10 richer in polyphenols than white wine). The review reports that low to moderate consumption of red wine 30-50g daily lowers risk factors for CVD, improve HDL lipid profile, exerts a beneficial effect on blood pressure (BP), promotes vasodilation thus helping to reduce plaques and finally limited data shows it may beneficially affect insulin resistance. Polyphenols in olives were reported to reduce blood pressure, reduce LDL lipids and increase HDL lipids, support weight loss and help prevent obesity, metabolic syndrome and type II diabetes, reduce inflammation and oxidative stress, and possibility benefit gut microbiota. The review concludes that both fluids exert cardio-protection when consumed in moderation as part of a MedDiet.
Abstract
A growing interest has emerged in the beneficial effects of plant-based diets for the prevention of cardiovascular disease, diabetes and obesity. The Mediterranean diet, one of the most widely evaluated dietary patterns in scientific literature, includes in its nutrients two fluid foods: olive oil, as the main source of fats, and a low-to-moderate consumption of wine, mainly red, particularly during meals. Current mechanisms underlying the beneficial effects of the Mediterranean diet include a reduction in inflammatory and oxidative stress markers, improvement in lipid profile, insulin sensitivity and endothelial function, as well as antithrombotic properties. Most of these effects are attributable to bioactive ingredients including polyphenols, mono- and poly-unsaturated fatty acids. Polyphenols are a heterogeneous group of phytochemicals containing phenol rings. The principal classes of red wine polyphenols include flavonols (quercetin and myricetin), flavanols (catechin and epicatechin), anthocyanin and stilbenes (resveratrol). Olive oil has at least 30 phenolic compounds. Among them, the main are simple phenols (tyrosol and hydroxytyrosol), secoroids and lignans. The present narrative review focuses on phenols, part of red wine and virgin olive oil, discussing the evidence of their effects on lipids, blood pressure, atheromatous plaque and glucose metabolism.
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The Effect of Probiotic Yogurt on Glycemic Control in Type 2 Diabetes or Obesity: A Meta-Analysis of Nine Randomized Controlled Trials.
Barengolts, E, Smith, ED, Reutrakul, S, Tonucci, L, Anothaisintawee, T
Nutrients. 2019;11(3)
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The metabolic disorders type 2 diabetes and obesity are highly prevalent worldwide. There are multiple merging treatments for type 2 diabetes and obesity, but the management of both conditions remains challenging. The aim of the study was to review the effects of probiotics on glycaemic outcomes in type 2 diabetes or obesity. The study is a meta-analysis of RCTs that utilized probiotic yoghurt as a main intervention in participants with type 2 diabetes or obesity. Nine studies were included in the meta-analysis, seven of which were conducted in subjects with type 2 diabetes and the rest were conducted in subjects with obesity. Results indicate that probiotic yoghurt provides no significant improvement compared with the control in glycaemic markers. Authors conclude that their study did not demonstrate the benefits of consuming probiotic yoghurt compared with conventional yoghurt for improving glucose control in patients with type 2 diabetes or obesity.
Abstract
Probiotic yogurt is suggested as a nutritional approach in type 2 diabetes (T2D) and obesity. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the effects of probiotic yogurt on glycemic outcomes in T2D or obesity. The databases used to search for RCTs included Medline and Scopus. The RCTs were eligible if outcomes included selected glycemic markers. In nine eligible trials, 237 and 235 subjects were in treatment (probiotic yogurt) and control (mostly conventional yogurt) groups, respectively. There was no significant difference for pooled unstandardized mean difference (USMD) hemoglobin A1c (HbA1c) by probiotic yogurt compared with the control in T2D (USMD: -0.366; 95% CI: -0.755, 0.024, p = 0.066) and obesity (USMD: 0.116, 95% CI: -0.007, 0.238, p = 0.065). Similarly, there were no effects of probiotic yogurt on fasting blood glucose, fasting insulin, or insulin resistance (estimated by homeostatic model assessment of insulin resistance (HOMA-IR)) in either T2D or obesity. In conclusion, the present meta-analysis has not demonstrated the benefits of consuming probiotic compared with conventional yogurt for improving glucose control in patients with diabetes or obesity. Larger trials are needed to verify the benefits of probiotic and/or conventional yogurt or other probiotic fermented milk (e.g., kefir) on glycemic markers in patients with diabetes and obesity.