The Effects of Dietary Fibres on Metabolic Health and the Gut Microbiome

Overview

The study involves intake of dietary supplements, which are commonly found in the UK diet (not pharmacological agents) to test their effects on inflammation in the body and gut microbiome composition. Study subjects will be healthy volunteers recruited from the University and local population and will be asked to attend the laboratory on 2 occasions; before and after 4-week' supplementing the diet daily with either the dietary fibres (the current trial focussed on pectin) or placebo (maltodextrin). At each study visit (\~3hrs), participants will be asked to provide a stool and blood sample and will have blood pressure measured. In the week before each study visit, participants will record their food intake.

The overall aim of the proposed project is to unlock the effect of dietary fibres (i.e. LM Pectin) on anti-inflammatory and cardioprotective metabolic responses via the modulation of the gut microbiome and SCFAs production. Specific Aim 1: To deliver a wealth of molecular data, including effect sizes, on the physiological effects of dietary fibres on the changes in the composition and function of the gut microbiome and changes in the metabolomic and physiological profile of an individual. Specific Aim 2: To investigate the mechanisms whereby the gut microbiome modulates crucial physiological parameters such, blood glucose regulation, hunger and appetite, immune function markers in response to the anti-inflammatory effects of the gut microbiome. 30 healthy, non-obese volunteers will be recruited following a successful medical screening. Between recruitment and first study visit, and in the final week of the 4-week intervention (before the second study visit), participants will be asked to complete a dietary record (4 days), to collect a stool sample on the day before the study visit and to fast from midnight the night before this visit. At both study visits, participants will have weight, hip/waist circumference and blood pressure measured. They will be asked to complete some questionnaires. After completion of the first study day, participants will be randomised to receive either the dietary fibre or placebo powder. They will be given the blinded products portioned in individual sachets, with instructions to add the contents of one sachet a day to juice, smoothies or water and to consume immediately. Study visit 2 will be scheduled at the end of the 4 week 'dosing' period.