The Effect of Micronutrient Supplementation on Gut Microbiome Composition and Function

Overview

The main aim of this randomized crossover study is to explore the effect of micronutrient supplementation on gut microbiota composition and function in healthy volunteers. Participants will undertake two 10-day trials with a replicated diet separated by a 15-day washout period. For one of these trials, participants will take a daily over-the-counter multivitamin supplement. Faecal and urine samples will be collected at the start and end of each trial to assess changes in gut microbiota composition, urinary and faecal metabolomics, and targeted bacterial metabolites including short chain fatty acids, sulphide, and lactate.

Exploring the effect of habitual dietary patterns on human gut microbiota and on host health is an area of scientific interest and a major funding theme in UKRI. The main aim of this proof-of-concept study is to explore the effect of micronutrient supplementation on gut microbiota composition and function in healthy volunteers. Participants will be asked to undertake two trials with 15 day washout in-between. If the participants are allocated to the "supplementation group" they will be asked to consume an over-the-counter multivitamin supplement for 10 days (1 tablet per day) in addition to their usual diet. Participants will provide faecal and urinary samples prior to initiation of the intervention and again at the end of the 10-day supplementation. During these 10 days participants will be asked to record the meals they consume on provided food diaries. If the participants are allocated to the "control group", participants will be asked to provide the same number of samples and at the same intervals as the supplementation group (i.e. at baseline and after 10 days) but without receiving micronutrient supplementation. Participants will also be asked to replicate as close as possible the diet they had followed during the first trial they were allocated. Between the two trials, participants will follow a wash-out period of 15 days with the aim of reverting the gut microbiota characteristics back to baseline levels. The main outcome measures of this study are to assess changes in gut microbiota composition based on 16S rRNA gene amplicon sequencing, changes in urinary/faecal metabolomics, and changes in targeted bacterial metabolites (short chain fatty acids, sulphide, lactate).