NCT05931562

The Impact of Diet on the Gut-Microbiota-Brain Axis

An Interventional Study on the Association Between Diet, Cognitive Function, Stress and the Gut Microbiota in Healthy Volunteers.

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 200 (estimated)
• Sponsor: University College Cork · Academic / Other
• Sex: All
• Age: 18 Years – 50 Years
• Healthy volunteers: Accepted

Summary

This study aims to investigate the effects of an 8-week dietary intervention on cognitive function, stress, and the gut microbiota in healthy adults with low fibre intake.

Detailed description

The gut microbiota communicates bidirectionally with the brain via the microbiota-gut-brain axis to influence various aspects of human physiology, including host metabolism, immune function, behaviour, and cognition. Diet is a key modulator of the microbial composition, suggesting that the microbiota could explain the association between poor nutrition and decreasing health of the population. Dietary fibre is the main energy source for the gut microbiota and fundamentally impacts its composition and function. The microbiota-gut-brain axis has been proposed to mediate some of the effects of dietary fibre on the brain, for example through microbial metabolites (e.g., short-chain fatty acids (SCFA)), regulation of the immune system, and the microbial impact on gut hormones and neurotransmitters. Similarly, intake of fermented foods is positively associated with cognitive health and has been shown to alter the microbiota composition and function and exert an anti-inflammatory effect. However, no studies to date have examined the singular and combined effects of fermented and fibrous foods on the gut microbiota, cognition, and emotion. The present study aims to determine the role of diet on the microbiota-gut-brain axis and mental health. Using a randomized-controlled, parallel, single-blinded design, participants consuming a habitually low fibre diet (N=200) will undergo an 8-week dietary intervention. Participants will receive one of four diets (n=50 in each group): high fibre (aim 24-35 grams/day), fermented foods (aim 4-6 portions/day), combined diet of fermented foods and high fibre (aim 25-30g/day of fibre and 3-4 servings/day of fermented foods) or control (dietary education according to national Irish guidelines). Cognitive, psychological, and biological measures will be compared at baseline and endpoint. During the intervention period, individuals will provide repeated faecal samples to assess temporal microbial changes.

Conditions

• Healthy

Interventions

Type	Name	Description
OTHER	Fermented Foods	Participants will recieve dietary education to include 4 to 6 portions of fermented foods to their normal diet.
OTHER	High Fibre	Participants will recieve dietary education to increase their fibre intake to 24-35g/day in their normal diet.
OTHER	Combined Diet	Participants will recieve dietary education to increase their fibre intake to 25-30g/day and include 3 to 4 portions of fermented foods to their normal diet.
OTHER	Control	Participants will recieve dietary education based on the Irish healthy food pyramid.

Timeline

• Start date: 2022-07-14
• Primary completion: 2026-07-01
• Completion: 2026-07-01
• First posted: 2023-07-05
• Last updated: 2024-07-16

Locations

1 site across 1 country: Ireland