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

Abstract

ObjectiveTo 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.DesignTwelve 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.ResultsBoth 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.ConclusionThese 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.

Adipokines and Adipose Tissue-Related Metabolites, Nuts and Cardiovascular Disease

“…In overweight adults, propionate levels in the intestinal colon were associated with weight gain prevention by increasing hormone release such as PYY and GLP-1 and, therefore, reduced energy intake [172]. In addition, propionate supplementation improved insulin sensitivity and reduced proinflammatory cytokine IL-8 in overweight or obese adults [173].…”

Microbial Medicine: Prebiotic and Probiotic Functional Foods to Target Obesity and Metabolic Syndrome

“…More recently, a study by Chambers et al investigating the physiological activity of inulin-propionate esters demonstrated that 20 g/day prebiotic supplementation elicited marked improvements to insulin sensitivity and systemic inflammatory markers compared with cellulose-supplemented controls [125]. Interestingly, this effect was associated with elevated stool concentrations of propionate, further highlighting the important role of SCFAs in mediating the insulin-sensitizing effects of prebiotics [125].…”

Calcium Oxalate Nephrolithiasis and Gut Microbiota: Not just a Gut-Kidney Axis. A Nutritional Perspective

“…The effects of insoluble fiber intake on gut microbiota composition are less known and generally considered negligible in comparison with that of soluble fibers such as inulin [139]. However, one study showed that the supply of different types of fibers, such as insoluble pectin vs. soluble inulin, resulted in the selective promotion of growth of different microbial communities in pH-controlled continuous-flow fermentors containing microbiota of human gut origin [134].…”