1.
A structured weight loss program increases gut microbiota phylogenetic diversity and reduces levels of Collinsella in obese type 2 diabetics: A pilot study.
Frost, F, Storck, LJ, Kacprowski, T, Gärtner, S, Rühlemann, M, Bang, C, Franke, A, Völker, U, Aghdassi, AA, Steveling, A, et al
PloS one. 2019;14(7):e0219489
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The global obesity epidemic is a major cause of the increase in type 2 diabetes mellitus (T2DM) and ensuing cardiovascular disease. The causes of obesity are complex ,and it has been shown that changes in the microbiome are associated with obesity. The microbiome can be altered through dietary intervention and weight loss. The aim of this open label pilot study was to investigate the microbiome of obese patients with T2DM during a weight loss programme. During the first six weeks the diet consisted of formula drink providing 800kcal per day, followed by nine weeks during which a regular diet of 1,200-1,500kcal per day was reintroduced, depending on the individuals’ needs. All participants lost weight continuously over the 15 weeks, from an average BMI of 39.6 at the start to 33.1 at the end of the programme. This was accompanied with an improvement in glucose metabolism, total and LDL cholesterol and uric acid levels, but not HDL cholesterol or triglycerides. All participants experienced changes in their microbiome towards greater diversity after the first six weeks of the low-calorie formula diet but these changes were partially reversed at the end of the study period at 15 weeks. A particular type of bacteria, Collinsella, which has been associated with poor metabolic health, was the only type found to remain reduced at the end of the 15 weeks, an 8.4-fold decrease. The authors hypothesise that this reduction in Collinsella may be associated with the improvement of metabolic factor in these patients at the end of the study.
Abstract
The global obesity epidemic constitutes a major cause of morbidity and mortality challenging public health care systems worldwide. Thus, a better understanding of its pathophysiology and the development of novel therapeutic options are urgently needed. Recently, alterations of the intestinal microbiome in the obese have been discussed as a promoting factor in the pathophysiology of obesity and as a contributing factor to related diseases such as type 2 diabetes and metabolic syndrome. The present pilot study investigated the effect of a structured weight loss program on fecal microbiota in obese type 2 diabetics. Twelve study subjects received a low-calorie formula diet for six weeks, followed by a nine week food reintroduction and stabilization period. Fecal microbiota were determined by 16S rRNA gene sequencing of stool samples at baseline, after six weeks and at the end of the study after fifteen weeks. All study subjects lost weight continuously throughout the program. Changes in fecal microbiota were most pronounced after six weeks of low-calorie formula diet, but reverted partially until the end of the study. However, the gut microbiota phylogenetic diversity increased persistently. The abundance of Collinsella, which has previously been associated with atherosclerosis, decreased significantly during the weight loss program. This study underlines the impact of dietary changes on the intestinal microbiome and further demonstrates the beneficial effects of weight loss on gut microbiota. Trial registration: ClinicalTrials.gov NCT02970838.
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Bread Affects Clinical Parameters and Induces Gut Microbiome-Associated Personal Glycemic Responses.
Korem, T, Zeevi, D, Zmora, N, Weissbrod, O, Bar, N, Lotan-Pompan, M, Avnit-Sagi, T, Kosower, N, Malka, G, Rein, M, et al
Cell metabolism. 2017;25(6):1243-1253.e5
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Bread is a key ingredient of the human diet. Wheat is the most commonly used cereal for baking bread. The aim of this study was to compare the effects of traditionally milled and prepared whole-grain sourdough bread and industrial white bread made from refined wheat on multiple clinical and disease markers and on the composition and function of the gut microbiome. The study is a randomized crossover trial with 20 healthy subjects. Participants received either industrial white bread made from mostly refined wheat flour or a sourdough-leavened bread made from whole-grain wheat flour. Results indicate that there were no significant differences on a broad array of clinical parameters between the two 1-week-long dietary interventions. Additionally, gut microbiome analysis showed that the microbiota composition remained generally stable and person specific throughout the trial. Authors conclude that their study underlines the importance of personalisation in dietary recommendations as the interpersonal variation in the effect of bread would allow the personalisation of bread-related nutritional recommendations and optimisation of food choices worldwide.
Abstract
Bread is consumed daily by billions of people, yet evidence regarding its clinical effects is contradicting. Here, we performed a randomized crossover trial of two 1-week-long dietary interventions comprising consumption of either traditionally made sourdough-leavened whole-grain bread or industrially made white bread. We found no significant differential effects of bread type on multiple clinical parameters. The gut microbiota composition remained person specific throughout this trial and was generally resilient to the intervention. We demonstrate statistically significant interpersonal variability in the glycemic response to different bread types, suggesting that the lack of phenotypic difference between the bread types stems from a person-specific effect. We further show that the type of bread that induces the lower glycemic response in each person can be predicted based solely on microbiome data prior to the intervention. Together, we present marked personalization in both bread metabolism and the gut microbiome, suggesting that understanding dietary effects requires integration of person-specific factors.