Objective This study investigated whether the levels of specific serum microRNAs (miRNAs) were altered following diet‐induced weight loss and whether the serum miRNAs differed in the presence of the metabolic syndrome. Methods The study was a weight loss intervention trial with a prescribed energy deficit of approximately 500 kcal/d. Levels of 22 miRNAs were determined in serum samples from 85 participants with overweight or obesity. miRNAs were analyzed using TaqMan Array miRNA Cards and normalized to the geometric mean of spiked‐in ath‐miR‐159a and U6 small nuclear RNA using the ΔCT method. Results The average weight loss was 5.7 kg (P < 0.001). miR‐122‐5p (−0.18 ± 0.06 log fold relative to initial, P < 0.01) and miR‐193a‐5p (−0.12 ± 0.04, P < 0.01) levels decreased in response to weight loss. miR‐126a‐3p (0.11 ± 0.04, P = 0.01) and miR‐222‐3p (1.51 ± 0.12, P < 0.001) levels increased. Furthermore, a higher level of miR‐122‐5p was observed at baseline in participants with the metabolic syndrome compared with participants without (0.28 ± 0.08, P < 0.01). Conclusions Changes in circulating miR‐122‐5p, miR‐126a‐3p, miR‐193a‐5p, and miR‐222‐3p in response to diet‐induced weight loss are demonstrated. Furthermore, assessment of miR‐122‐5p could be an indicator of an adverse metabolic health status independent of obesity.

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and on behalf of the MyNewGut consortiumScope: Dietary-based strategies are regularly explored in controlled clinical trials to provide cost-effective therapies to tackle obesity and its comorbidities. The article presents a complementary analysis based on a multivariate multi-omics approach of a caloric restriction intervention (CRD) with fiber supplementation to unveil synergic effects on body weight control, lipid metabolism, and gut microbiota. Methods and results: The study explores fecal bile acids (BAs) and short-chain fatty acids (SCFAs), plasma BAs, and fecal shotgun metagenomics on 80 overweight participants of a 12-week caloric restriction clinical trial (−500 kcal day −1 ) randomly allocated into fiber (10 g day −1 inulin + 10 g day −1 resistant maltodextrin) or placebo (maltodextrin) supplementation groups. The multi-omic data integration analysis uncovered the benefits of the fiber supplementation and/or the CRD (e.g., increase of Parabacteroides distasonis and fecal propionate), showing sex-specific effects on either adiposity and fasting insulin; effects thought to be linked to changes of specific gut microbiota species, functional genes, and bacterially produced metabolites like SCFAs and secondary BAs. Conclusions: This study identifies diet-microbe-host interactions helping to design personalised interventions. It also suggests that sex perspective should be considered routinely in future studies on dietary interventions efficacy. All in all, the study uncovers that the dietary intervention is more beneficial for women than men.

Angiopoietin-like protein 4 (ANGPTL4) is a lipoprotein lipase inhibitor that is involved in lipid metabolism and angiogenesis. Animal studies have suggested that the ANGPTL4 protein is modulated by the gut microbiota, possibly through increased concentrations of SCFA, such as C4, found in whole-fat milk or as a result of fermentation of inulin. This study investigated whether a standardised diet either high in fat content or supplemented with inulin powder would increase plasma ANGPTL4 in overweight men and whether this increase was mediated through a compositional change of the gut microbiota. The study had a crossover design with three arms, where participants were given a standardised isoenergetic diet supplemented with inulin powder, whole-fat milk or water (control). Plasma and urine samples were collected before and after each intervention period. Faecal samples and adipose tissue biopsies were collected after each intervention period. The study included twenty-one participants of whom eighteen completed the study. The dietary interventions did not change ANGPTL4 plasma concentration, nor was plasma ANGPTL4 associated with plasma lipids, TAG or NEFA concentration. The relative abundance of bifidobacteria following the inulin diet was higher, compared with the control diet. However, the changes in microbiota were not associated with plasma ANGPTL4 and the overall composition of the microbiota did not change between the dietary periods. Although weight was maintained throughout the dietary periods, weight was negatively associated with plasma ANGPTL4 concentration. In the adipose tissue, ANGPTL4 expression was correlated with leptin expression, but not with hypoxia-inducible factor 1α (HIF-1α) expression.