Scope: The aim of this study is to investigate acute postprandial responses to intake of meals typical for Mediterranean and Western diets. Methods: In a randomized crossover design, overweight and obese participants with a risk phenotype for cardiometabolic diseases consumed three different isoenergetic meals: Western diet-like high-fat (WDHF), Western diet-like high-carbohydrate (WDHC), and Mediterranean diet (MED) meal. Blood samples are collected at fasting and 1, 2, 3, 4, 5 h postprandially and analyzed for parameters of lipid and glucose metabolism, inflammation, oxidation, and antioxidant status. Results: Compared to MED and WDHF meals, intake of a WDHC meal results in prolonged and elevated increases in glucose and insulin. Elevations for triglycerides are enhanced after the WDHF meal compared to the MED and the WDHC meal. Glucagon-like peptide-1 and interleukin-6 increase postprandially without meal differences. Apart from vitamin C showing an increase after the MED meal and a decrease after WDHF and WDHC meals, antioxidant markers decrease postprandially without meal differences. Plasma interleukin-1 is not affected by meal intake. Conclusions: Energy-rich meals induce hyperglycemia, hyperlipemia, an inflammatory response, and a decrease in antioxidant markers.

Type 2 diabetes is a combined disease, resulting from a hyperglycemia and peripheral and hepatic insulin resistance. Recent data suggest that the gut microbiota is involved in diabetes development, altering metabolic processes including glucose and fatty acid metabolism. Thus, type 2 diabetes patients show a microbial dysbiosis, with reduced butyrate-producing bacteria and elevated potential pathogens compared to metabolically healthy individuals. Furthermore, probiotics are a known tool to modulate the microbiota, having a therapeutic potential. Current literature will be discussed to elucidate the complex interaction of gut microbiota, intestinal permeability and inflammation leading to peripheral and hepatic insulin resistance. Therefore, this review aims to generate a deeper understanding of the underlying mechanism of potential microbial strains, which can be used as probiotics.

Background Nonalcoholic fatty liver disease (NAFLD) is frequent among patients undergoing bariatric surgery. Beyond weight reduction, dietary supplements like micronutrients or probiotics that modify insulin resistance and lipotoxicity can be used to prevent or delay the progression of liver disease. Objectives We evaluated the effect of a dietary approach with a specifically tailored multistrain probiotic and micronutrient mixture compared with a basic care micronutrient supplement on serum alanine aminotransferase (ALAT) in obese patients after mini gastric bypass (MGB) surgery. Methods This randomized, double-blind, controlled trial included 60 obese patients (age: 40 ± 10 y; BMI: 44 ± 3 kg/m²). Patients received a combination of specifically tailored multistrain probiotic powder and a specific micronutrient mixture (Pro+SM) or a control treatment consisting of a placebo and a basic care micronutrient mixture (Con+BM), with some micronutrients in lower doses than SM, for 12 wk after hospital discharge. Primary (serum ALAT) and secondary outcomes [serum aspartate aminotransferase (ASAT), fatty liver index, NAFLD fibrosis score, glucose metabolism, blood pressure (BP), heart rate] were assessed at week 0 and week 12. Data were analyzed using unpaired Student's t-tests or Mann-Whitney U tests to compare the changes due to each treatment to one another. Results A total of 48 patients were included in the analyses. Changes in serum ALAT concentrations did not differ between groups. Compared with Con+BM, Pro+SM improved serum ASAT (difference: –8.0 U/L, 95% CI: –17.0, –4.0; P = 0.043), NAFLD fibrosis score (difference: –0.39; 95% CI: –0.78, 0; P = 0.048), serum triglycerides (difference: –22.8 mg/dL; 95% CI: –45.6, –0.1; P = 0.049) and the visceral adiposity index (difference: –0.70; 95% CI: –1.31, –0.08; P = 0.027). Conclusion Supplementation with a specifically tailored probiotic and micronutrient mixture improved NAFLD-related markers more than a basic micronutrient mixture in obese patients following MGB surgery. The trial was registered under clinicaltrials.gov as NCT03585413.

Purpose Low-grade inflammation in obesity is associated with insulin resistance and other metabolic disturbances. In response to high-energy meal intake, blood concentrations of inflammatory markers, glucose and insulin rise. The aim of this study was to examine whether a basal inflammatory state influences postprandial responses. Methods A randomized crossover trial was performed in 60 participants with a cardiometabolic risk phenotype (age 70 ± 5 years; BMI 30.9 ± 3.1 kg/m2). Each participant consumed three different iso-energetic meals (4300 kJ): a Western diet-like high-fat meal (WDHF), a Western diet-like high-carbohydrate meal (WDHC) and a Mediterranean diet-like meal (MED). Blood samples were collected when fasted and hourly for 5 h postprandially and analyzed for glucose, insulin, interleukin-1β (IL-1β), interleukin-6 (IL-6) and endothelial adhesion molecules. Based on fasting serum C-reactive protein (CRP) concentrations, participants were assigned to a high inflammation (CRP ≥ 2.0 mg/L; n = 30) or low inflammation (CRP < 2.0 mg/L; n = 30) group, and postprandial outcomes were compared. Results Plasma IL-6, glucose and serum insulin increased after all meals, while IL-1β and endothelial adhesion molecules were unchanged. The high inflammation group had higher fasting and postprandial IL-6 concentrations than the low inflammation group, although the IL-6 response slope was similar between groups. In response to the WDHC meal, participants in the high inflammation group experienced a higher glycaemic response than those in the low inflammation group. Conclusion A basal proinflammatory state results in higher absolute fasting and postprandial IL-6 concentrations, but the increase in IL-6 relative to basal levels is not different between high and low inflammation groups. Elevated glycaemic response in the high inflammation group may be due to inflammation-induced short-term insulin resistance. The trial was registered at http://www.germanctr.de and http://www.drks.de under identifier DRKS00009861 (registration date, January 22, 2016).

Bariatric surgery leads to sustained weight loss and the resolution of obesity-related comorbidities. Recent studies have suggested that changes in gut microbiota are associated with the weight loss induced by bariatric surgery. Several studies have observed major changes in the microbial composition following gastric bypass surgery. However, there are inconsistencies between the reported alterations in microbial compositions in different studies. Furthermore, it is well established that diet is an important factor shaping the composition and function of intestinal microbiota. However, most studies on gastric bypass have not assessed the impact of dietary intake on the microbiome composition in general, let alone the impact of restrictive diets prior to bariatric surgery, which are recommended for reducing liver fat content and size. Thus, the relative impact of bariatric surgery on weight loss and gut microbiota remains unclear. Therefore, this review aims to provide a deeper understanding of the current knowledge of the changes in intestinal microbiota induced by bariatric surgery considering pre-surgical nutritional changes.