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Randomized controlled trial demonstrates response to a probiotic intervention for metabolic syndrome that may correspond to diet.
Wastyk, HC, Perelman, D, Topf, M, Fragiadakis, GK, Robinson, JL, Sonnenburg, JL, Gardner, CD, Sonnenburg, ED
Gut microbes. 2023;15(1):2178794
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Rates of metabolic syndrome are high throughout developed countries. Metabolic syndrome is a cluster of conditions that occur together and increase your risk for heart disease, stroke, and type 2 diabetes. Studies in animals and humans have shown that the composition of the gut microbiome may be linked to metabolic syndrome and that it is affected by diet. This randomised control trial of 39 individuals showed that the supplementation of a probiotic containing three different probiotic strains did not have a population wide effect but did influence a subset of individuals. These individuals had a different microbiome by the end of the trial and a decrease in blood pressure and blood lipids. Interestingly these individuals also had a higher dietary intake of sugar, yet a lower blood sugar level. It was concluded that the response to probiotic supplements may be dependent upon an individual’s diet. This study could be used by healthcare professionals to understand that diet may influence the success of probiotics, however more research is warranted before firm conclusions are made on the optimal diet during supplementation.
Abstract
An individual's immune and metabolic status is coupled to their microbiome. Probiotics offer a promising, safe route to influence host health, possibly via the microbiome. Here, we report an 18-week, randomized prospective study that explores the effects of a probiotic vs. placebo supplement on 39 adults with elevated parameters of metabolic syndrome. We performed longitudinal sampling of stool and blood to profile the human microbiome and immune system. While we did not see changes in metabolic syndrome markers in response to the probiotic across the entire cohort, there were significant improvements in triglycerides and diastolic blood pressure in a subset of probiotic arm participants. Conversely, the non-responders had increased blood glucose and insulin levels over time. The responders had a distinct microbiome profile at the end of the intervention relative to the non-responders and placebo arm. Importantly, diet was a key differentiating factor between responders and non-responders. Our results show participant-specific effects of a probiotic supplement on improving parameters of metabolic syndrome and suggest that dietary factors may enhance stability and efficacy of the supplement.
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High-fiber diet ameliorates gut microbiota, serum metabolism and emotional mood in type 2 diabetes patients.
Chen, L, Liu, B, Ren, L, Du, H, Fei, C, Qian, C, Li, B, Zhang, R, Liu, H, Li, Z, et al
Frontiers in cellular and infection microbiology. 2023;13:1069954
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Accumulating studies have demonstrated that there are strong correlations between type 2 diabetes mellitus (T2DM) and gut microbiota. A nutritious diet composed of an adequate level of dietary fibres could provide enough carbohydrates for the gut microbiota to ferment, and the microbial metabolites could provide energy supply and regulate the immune function of the host. The aim of this study was to analyse the changes in gut microbiota, serum metabolism and emotional mood of patients with T2DM after consumption of a high-fibre diet. This study was a randomised, open-label, parallel-group clinical trial in T2DM patients with a 4-week treatment period. Seventeen patients clinically diagnosed with T2DM enrolled in the clinical trial and were randomly assigned into two groups: the control group (n = 8) or the intervention group (n = 9). Results showed that the high-fibre diet (compared to the control group): - improved glucose homeostasis and lipid metabolism of participants with T2DM; - decreased serum levels of inflammatory chemokines in participants with T2DM; - alleviated depression and anxiety symptoms, particularly by the uptake of more diverse carbohydrates in the diet in participants with T2DM; - enhanced the diversity of gut microbiota in the treatment group. Authors conclude that the dietary source of fibre demonstrated protective impacts on the gut ecosystem, and the alteration of the gut microbiota composition improved the glucose homeostasis in patients with T2DM.
Abstract
Previous studies have demonstrated that patients with type 2 diabetes mellitus (T2DM) often had the problems of fecal microbiota dysbiosis, and were usually accompanied with psychiatric comorbidities (such as depression and anxiety). Here, we conducted a randomized clinical study to analyze the changes in gut microbiota, serum metabolism and emotional mood of patients with T2DM after consumption of a high-fiber diet. The glucose homeostasis of participants with T2DM was improved by the high-fiber diet, and the serum metabolome, systemic inflammation and psychiatric comorbidities were also altered. The increased abundances of Lactobacillus, Bifidobacterium and Akkermansias revealed that the proportions of beneficial gut microbes were enriched by the high-fiber diet, while the abundances of Desulfovibrio, Klebsiella and other opportunistic pathogens were decreased. Therefore, the current study demonstrated that the intestinal microbiota alterations which were influenced by the high-fiber diet could improve the serum metabolism and emotional mood of patients with T2DM.
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Effects of galactooligosaccharides on maternal gut microbiota, glucose metabolism, lipid metabolism and inflammation in pregnancy: A randomized controlled pilot study.
Wan, J, An, L, Ren, Z, Wang, S, Yang, H, Ma, J
Frontiers in endocrinology. 2023;14:1034266
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During pregnancy, a disordered gut microbiome and abnormal glucose metabolism may be possible mechanisms for pregnancy complications such as gestational diabetes mellitus (GDM). Different from probiotics, galactooligosaccharides (GOS) is a prebiotic that is not digested and absorbed by the host, but can selectively promote the metabolism and proliferation of beneficial bacteria in the body, particularly Lactobacillus and Bifidobacterium. The aim of this study was to evaluate the feasibility, acceptability, and safety of prebiotic intervention in healthy pregnant women, and conduct a preliminary exploration of the possible benefits for pregnant women. This study was a prospective double-blinded randomised clinical trial involving pregnant women. Participants were randomly assigned to the control group and the intervention group at a 1:1 ratio. Results showed that GOS intervention had no significant effect on reducing the incidence of GDM and improving glucose and lipid metabolism. Furthermore, there was no significant difference in glucose and lipid metabolism levels between GOS group and placebo group. Authors conclude that GOS can be considered as a dietary supplement during pregnancy. However, further clinical studies are needed to strengthen the findings of this study.
Abstract
BACKGROUND Gut microbiota of pregnant women change with the gestational week. On the one hand, they participate in the metabolic adaptation of pregnant women. On the other hand, the abnormal composition of gut microbiota of pregnant women is more likely to suffer from gestational diabetes mellitus (GDM). Therefore, gut microbiota targeted treatment through dietary supplements is particularly important for prevention or treatment. Prebiotic supplements containing galactooligosaccharides (GOS) may be an intervention method, but the effect is still unclear. OBJECTIVE This study aims to evaluate the feasibility and acceptability of prebiotic intervention in healthy pregnant women during pregnancy, and to explore the possible effects of intervention on pregnant women and the influence on gut microbiota as preliminaries. METHODS After recruitment in first trimester, 52 pregnant women were randomly assigned to receive GOS intervention or placebo containing fructooligosaccharides. 16S rRNA sequencing technology was used to detect the composition, diversity and differential flora of gut microbiota. Lipid metabolism, glucose metabolism and inflammatory factors during pregnancy were also analyzed. RESULTS The adverse symptoms of GOS intervention are mild and relatively safe. For pregnant women, there was no significant difference in the GDM incidence rates and gestational weight gain (GWG) in the GOS group compared with placebo (P > 0.05). Compared with the placebo group, the levels of FPG, TG, TC, HDL-C LDL-C, and IL-6 had no significant difference in GOS group (P > 0.05). For newborns, there was no significant difference between GOS group and placebo group in the following variables including gestational week, birth weight, birth length, head circumference, chest circumference, sex, and delivery mode (P > 0.05). And compared with the placebo group, the GOS group had a higher abundance of Paraprevotella and Dorea, but lower abundance of LachnospiraceaeUCG_001. CONCLUSIONS GOS prebiotics appear to be safe and acceptable for the enrolled pregnancies. Although GOS intervention did not show the robust benefits on glucose and lipid metabolism. However, the intervention had a certain impact on the compostion of gut microbiota. GOS can be considered as a dietary supplement during pregnancy, and further clinical studies are needed to explore this in the future.
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Differential Responders to a Mixed Meal Tolerance Test Associated with Type 2 Diabetes Risk Factors and Gut Microbiota-Data from the MEDGI-Carb Randomized Controlled Trial.
Skantze, V, Hjorth, T, Wallman, M, Brunius, C, Dicksved, J, Pelve, EA, Esberg, A, Vitale, M, Giacco, R, Costabile, G, et al
Nutrients. 2023;15(20)
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Type 2 diabetes (T2D) is a growing worldwide health problem. Increased blood sugars and a corresponding increase in the production of the hormone insulin, which functions to lower blood sugar are risk factors for T2D development. However, it has been shown that everyone has an individual response to the food and the production of differing levels of blood sugar and insulin when eating the same meals has been shown. This secondary analysis of a 12-week randomised control trial of 155 individuals aimed to determine relationships between gut microbiota composition and the glucose response to high and low glycaemic index Mediterranean diets. The results identified two distinct types of response amongst the participants. Cluster A individuals had a lower but more rapid glucose response following food and were deemed to have a better glucose control than cluster B individuals. The clusters also differed in the gut microbiota composition. Cluster A had a higher proportion of Clostridium sensu stricto 1 and a lower proportion of Blautia, than cluster B. It was concluded that the glucose response to a standardised meal can differ between individuals and are associated with differing gut microbiota and risk for T2D. This study could be used by healthcare professionals to understand that diet recommendations are not one size fits all and that the recommendation of certain diets may have differing success. Understanding and differentiating individuals and tailor making recommendations may be of benefit, however further understanding is required on different glucose responses following a meal.
Abstract
The global prevalence of type 2 diabetes mellitus (T2DM) has surged in recent decades, and the identification of differential glycemic responders can aid tailored treatment for the prevention of prediabetes and T2DM. A mixed meal tolerance test (MMTT) based on regular foods offers the potential to uncover differential responders in dynamical postprandial events. We aimed to fit a simple mathematical model on dynamic postprandial glucose data from repeated MMTTs among participants with elevated T2DM risk to identify response clusters and investigate their association with T2DM risk factors and gut microbiota. Data were used from a 12-week multi-center dietary intervention trial involving high-risk T2DM adults, comparing high- versus low-glycemic index foods within a Mediterranean diet context (MEDGICarb). Model-based analysis of MMTTs from 155 participants (81 females and 74 males) revealed two distinct plasma glucose response clusters that were associated with baseline gut microbiota. Cluster A, inversely associated with HbA1c and waist circumference and directly with insulin sensitivity, exhibited a contrasting profile to cluster B. Findings imply that a standardized breakfast MMTT using regular foods could effectively distinguish non-diabetic individuals at varying risk levels for T2DM using a simple mechanistic model.
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The Roles of Probiotics in the Gut Microbiota Composition and Metabolic Outcomes in Asymptomatic Post-Gestational Diabetes Women: A Randomized Controlled Trial.
Hasain, Z, Raja Ali, RA, Ahmad, HF, Abdul Rauf, UF, Oon, SF, Mokhtar, NM
Nutrients. 2022;14(18)
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Gestational Diabetes Mellitus (GDM) happens to some pregnant women during the second and third trimester of their pregnancy, increasing the risk of developing Type 2 Diabetes Mellitus by 10-fold later in life. Aberrant changes to the gut microbial composition in pregnant gestational diabetic women are found to have a negative effect on the metabolism that may carry on to the postpartum period. On the other hand, probiotics may have a host metabolism modifying effect by reducing inflammation and gut dysbiosis in asymptomatic post-GDM women. This 12-week randomised, double-blinded, controlled, parallel-group clinical trial looked at the effect of probiotic supplementation on inflammatory and metabolic outcomes in asymptomatic post-GDM women. The one hundred and thirty-two participants were randomised to receive either a probiotic formulation containing Lactobacillus and Bifidobacterium stains or a placebo. Participants in the probiotic group showed a significant improvement in fasting blood glucose, HbA1c, total cholesterol, triglycerides and high-sensitivity C-reactive protein compared to the placebo group. In addition, the probiotic supplementation led to an increase in Bifidobacterium adolescentis. Healthcare professionals can use the results of this study to understand the beneficial effects of probiotic supplements in post-GDM women. However, further robust studies are required to evaluate the functions of probiotic supplements in post-GDM women from different backgrounds.
Abstract
Probiotics are widely used as an adjuvant therapy in various diseases. Nonetheless, it is uncertain how they affect the gut microbiota composition and metabolic and inflammatory outcomes in women who have recently experienced gestational diabetes mellitus (post-GDM). A randomized, double-blind, placebo-controlled clinical trial involving 132 asymptomatic post-GDM women was conducted to close this gap (Clinical Trial Registration: NCT05273073). The intervention (probiotics) group received a cocktail of six probiotic strains from Bifidobacterium and Lactobacillus for 12 weeks, while the placebo group received an identical sachet devoid of living microorganisms. Anthropometric measurements, biochemical analyses, and 16S rRNA gene sequencing results were evaluated pre- and post-intervention. After the 12-week intervention, the probiotics group's fasting blood glucose level significantly decreased (mean difference -0.20 mmol/L; p = 0.0021). The HbA1c, total cholesterol, triglycerides, and high-sensitivity C-reactive protein levels were significantly different between the two groups (p < 0.05). Sequencing data also demonstrated a large rise in the Bifidobacterium adolescentis following probiotic supplementation. Our findings suggest that multi-strain probiotics are beneficial for improved metabolic and inflammatory outcomes in post-GDM women by modulating gut dysbiosis. This study emphasizes the necessity for a comprehensive strategy for postpartum treatment that includes probiotics to protect post-GDM women from developing glucose intolerance.
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White common bean extract remodels the gut microbiota and ameliorates type 2 diabetes and its complications: A randomized double-blinded placebo-controlled trial.
Feng, Y, Zhu, J, Wang, Q, Cao, H, He, F, Guan, Y, Li, D, Yan, J, Yang, J, Xia, Y, et al
Frontiers in endocrinology. 2022;13:999715
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Patients with type 2 diabetes (T2D) have a higher risk of macrovascular complications. Intensive glycaemic control reduces microvascular complications and exerts a modest improved effect on macrovascular outcomes. The main aim of this study was to explore the effects of white common bean extract (WCBE) on glucose metabolism and diabetic complications in patients with T2D. This study was a randomised double-blind placebo-controlled trial which enrolled ninety-six patients with T2D aged between 35 and 75 years. Participants were randomly assigned in a 1:2 ratio to the control group and WCBE group. Results showed that WCBE alleviated glucose metabolism dysbiosis and diabetic complication indices. In fact, after 2 months of an intense intervention with a WCBE treatment and in the following two-month maintenance period, the improvements to glycaemic metabolism were preserved. Furthermore, there was notable improvement of the structure of the gut microbiota, especially the enrichment of short-chain fatty acid-producing bacteria and inhibition of opportunistic pathogens. Authors conclude that WCBE may be considered as a novel prebiotic antidiabetic agent for the regulation of glucose metabolism and gut microbiota homeostasis and may slightly ameliorate diabetic complications in patients with T2D.
Abstract
OBJECTIVE Excessive carbohydrate intake is a high risk factor for increased morbidity of type 2 diabetes (T2D). A novel regimen for the dietary care of diabetes that consists of a highly active α-amylase inhibitor derived from white common bean extract (WCBE) and sufficient carbohydrates intake was applied to attenuate T2D and its complications. Furthermore, the role of gut microbiota in this remission was also investigated. METHODS We conducted a 4-month randomized double-blinded placebo-controlled trial. During the intense intervention period, ninety subjects were randomly assigned to the control group (Group C) and WCBE group (Group W). Subjects in Group C were supplemented with 1.5 g of maltodextrin as a placebo. Subjects in Group W took 1.5 g of WCBE half an hour before a meal. Fifty-five participants continued the maintenance intervention receiving the previous dietary intervention whereas less frequent follow-up. The variation in biochemical, vasculopathy and neuropathy indicators and the structure of the fecal microbiota during the intervention was analyzed. RESULT Glucose metabolism and diabetic complications showed superior remission in Group W with a 0.721 ± 0.742% decline of glycosylated hemoglobin after 4 months. The proportion of patients with diabetic peripheral neuropathy (Toronto Clinical Scoring System, TCSS ≥ 6) was significantly lower in Group W than in Group C. Both the left and right sural sensory nerve conduction velocity (SNCV-left sural and SNCV-right sural) slightly decreased in Group C and slightly increased in Group W. Additionally, the abundances of Bifidobacterium, Faecalibacterium and Anaerostipes were higher in Group W, and the abundances of Weissella, Klebsiella, Cronobacter and Enterobacteriaceae_unclassified were lower than those in Group C at month 2. At the end of month 4, Bifidobacterium remained more abundant in Group W. CONCLUSION To our knowledge, this is the first report of improvement to diabetes complications by using a dietary supplement in such a short-term period. The enrichment of SCFA-producing bacteria might be responsible for the attenuation of T2D and its complications. CLINICAL TRIAL REGISTRATION NUMBER http://www.chictr.org.cn/edit.aspx?pid=23309&htm=4, identifier ChiCTR-IOR-17013656.
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Effects of Synbiotic Supplement on Human Gut Microbiota, Body Composition and Weight Loss in Obesity.
Sergeev, IN, Aljutaily, T, Walton, G, Huarte, E
Nutrients. 2020;12(1)
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The gut microbiota plays a role in the development of obesity and associated diseases. Whilst energy-restricted, low-carbohydrate, high-protein diets can facilitate substantial weight-loss, they also have been linked to ill-effects and unfavourable changes in the gut microbiota from excess protein fermentation. Pro-and prebiotics (synbiotics) have become a promising intervention in the management of obesity. This small placebo-controlled clinical trial involved 20 obese adults following an energy-restricted (approx.950 kcal/day) low-carbohydrate, high-protein diet. The study examined whether a supplementary synbiotic contributed to additional changes in body composition and metabolic biomarkers. The synbiotic contained Lactobacilli spp. and Bifidobacteria spp. and a prebiotic mixture of galactooligosaccharides. Overall, at the end of the 3-month trial, there was no remarkable difference between the groups. Both experienced a significant and decreasing trend in body mass, waist circumference, body mass index, fat mass, fat percentage, and glucose level, affirming the known benefits of the described weight-loss diet. However, the synbiotic supplementation group had a greater decrease in HbA1C and significant alterations in gut microbiota, showing an increased abundance of gut bacteria associated with positive health effects. Due to the complexity of microbial species and host interactions, the authors advocate for more research to identify their significance and shed light on contradictory findings. This study identified that synbiotics may not contribute to additional changes in body composition when combined with an energy-restricted, low-carbohydrate, high-protein diet but they can offer additional health benefits by inducing favourable changes to the gut microbiota.
Abstract
Targeting gut microbiota with synbiotics (probiotic supplements containing prebiotic components) is emerging as a promising intervention in the comprehensive nutritional approach to reducing obesity. Weight loss resulting from low-carbohydrate high-protein diets can be significant but has also been linked to potentially negative health effects due to increased bacterial fermentation of undigested protein within the colon and subsequent changes in gut microbiota composition. Correcting obesity-induced disruption of gut microbiota with synbiotics can be more effective than supplementation with probiotics alone because prebiotic components of synbiotics support the growth and survival of positive bacteria therein. The purpose of this placebo-controlled intervention clinical trial was to evaluate the effects of a synbiotic supplement on the composition, richness and diversity of gut microbiota and associations of microbial species with body composition parameters and biomarkers of obesity in human subjects participating in a weight loss program. The probiotic component of the synbiotic used in the study contained Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, and Bifidobacterium bifidum and the prebiotic component was a galactooligosaccharide mixture. The results showed no statistically significant differences in body composition (body mass, BMI, body fat mass, body fat percentage, body lean mass, and bone mineral content) between the placebo and synbiotic groups at the end of the clinical trial (3-month intervention, 20 human subjects participating in weight loss intervention based on a low-carbohydrate, high-protein, reduced energy diet). Synbiotic supplementation increased the abundance of gut bacteria associated with positive health effects, especially Bifidobacterium and Lactobacillus, and it also appeared to increase the gut microbiota richness. A decreasing trend in the gut microbiota diversity in the placebo and synbiotic groups was observed at the end of trial, which may imply the effect of the high-protein low-carbohydrate diet used in the weight loss program. Regression analysis performed to correlate abundance of species following supplementation with body composition parameters and biomarkers of obesity found an association between a decrease over time in blood glucose and an increase in Lactobacillus abundance, particularly in the synbiotic group. However, the decrease over time in body mass, BMI, waist circumstance, and body fat mass was associated with a decrease in Bifidobacterium abundance. The results obtained support the conclusion that synbiotic supplement used in this clinical trial modulates human gut microbiota by increasing abundance of potentially beneficial microbial species.
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Dietary supplementation with inulin-propionate ester or inulin improves insulin sensitivity in adults with overweight and obesity with distinct effects on the gut microbiota, plasma metabolome and systemic inflammatory responses: a randomised cross-over trial.
Chambers, ES, Byrne, CS, Morrison, DJ, Murphy, KG, Preston, T, Tedford, C, Garcia-Perez, I, Fountana, S, Serrano-Contreras, JI, Holmes, E, et al
Gut. 2019;68(8):1430-1438
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Literature shows that higher intakes of dietary fibre are associated with a reduced risk of type 2 diabetes. The main aim of this study was to elucidate the underlying mechanisms behind improvements in glucose homeostasis following long-term delivery of propionate (a short-chain fatty acid produced by human gut microbiota in response to dietary fibre) to the human colon. The study is a randomised, double-blind, placebo-controlled cross over trial. Fourteen participants randomly received 20 g/day of a low-fermentable fibre control, a high-fermentable fibre control and inulin-propionate ester (IPE) for 42 days each. Results indicate that stool concentrations of short-chain fatty acids were not different following the three supplementation periods. Furthermore, dietary supplementation with 20 g/day IPE promoted no superior impacts on measures of glucose homeostasis compared with inulin (high-fermentable fibre), yet both IPE and inulin improved insulin resistance relative to cellulose (low-fermentable fibre). Authors conclude that manipulating the colonic fermentation profile of a dietary fibre in favour of propionate promotes selective effects on the mechanisms that contribute to metabolic dysregulation.
Abstract
OBJECTIVE To investigate the underlying mechanisms behind changes in glucose homeostasis with delivery of propionate to the human colon by comprehensive and coordinated analysis of gut bacterial composition, plasma metabolome and immune responses. DESIGN Twelve non-diabetic adults with overweight and obesity received 20 g/day of inulin-propionate ester (IPE), designed to selectively deliver propionate to the colon, a high-fermentable fibre control (inulin) and a low-fermentable fibre control (cellulose) in a randomised, double-blind, placebo-controlled, cross-over design. Outcome measurements of metabolic responses, inflammatory markers and gut bacterial composition were analysed at the end of each 42-day supplementation period. RESULTS Both IPE and inulin supplementation improved insulin resistance compared with cellulose supplementation, measured by homeostatic model assessment 2 (mean±SEM 1.23±0.17 IPE vs 1.59±0.17 cellulose, p=0.001; 1.17±0.15 inulin vs 1.59±0.17 cellulose, p=0.009), with no differences between IPE and inulin (p=0.272). Fasting insulin was only associated positively with plasma tyrosine and negatively with plasma glycine following inulin supplementation. IPE supplementation decreased proinflammatory interleukin-8 levels compared with cellulose, while inulin had no impact on the systemic inflammatory markers studied. Inulin promoted changes in gut bacterial populations at the class level (increased Actinobacteria and decreased Clostridia) and order level (decreased Clostridiales) compared with cellulose, with small differences at the species level observed between IPE and cellulose. CONCLUSION These data demonstrate a distinctive physiological impact of raising colonic propionate delivery in humans, as improvements in insulin sensitivity promoted by IPE and inulin were accompanied with different effects on the plasma metabolome, gut bacterial populations and markers of systemic inflammation.
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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.