The Relationship Between Diet, Cognition, Stress, and the Gut Microbiota (NMB)

The Relationship Between Diet, Cognition, Stress, and the Gut Microbiota: A Cross-sectional Study in Healthy Adults

This study aims to investigate the relationship between diet and the microbiota-gut-brain axis.

Study Overview

• Status: Recruiting
• Conditions: Healthy
• Intervention / Treatment: Other: Dietary fibre

Detailed Description

Dietary fibre is well-known for its many health benefits, including the support of gastrointestinal, metabolic, and mental health. Although studies investigating whole dietary patterns in relation to cognition have demonstrated that diet quality and a healthy dietary pattern are associated with better cognitive performance, the role of dietary fibre in this regard is understudied. It is now understood that the gut microbiota (trillions of microbes inhabiting the gastrointestinal tract) communicates bidirectionally with the brain to influence mental health and cognition. Importantly, dietary fibre has been shown to positively affect the microbiota composition. The aim of this study is to understand the effects of dietary fibre on the microbiota-gut-brain axis.

Using a cross-sectional design, habitual low fibre (<=18 grams/day, n=200), moderate fibre (18.1-24.9 grams/day, n=75), and high fibre (=>25 g/day, n=75) consumers will be compared at baseline on measures of cognition, responses to acute and chronic stress, and biological markers of the microbiota-gut-brain axis.

The investigators hypothesize that participants with higher dietary fibre intake at baseline will perform better in the cognitive tasks compared to individuals with low fibre intake, and that this difference can, in part, be mediated by the gut microbiota.

• Study Type: Observational
• Enrollment (Estimated): 350

Contacts and Locations

• Study Contact: Name: Elizabeth Schneider, PhD; Phone Number: (+353) 021 4901721; Email: eschneider@ucc.ie
• Study Contact Backup: Name: Revathy Munuswamy, PhD; Phone Number: (+353) 021 4901721; Email: RMunuswamy@ucc.ie

Study Locations

• Ireland
  • Cork, Ireland, T12YT20
    • Recruiting
    • APC Microbiome Ireland
    • Principal Investigator: John F Cryan, PhD
    • Contact: Revathy Munuswamy, PhD; Phone Number: (+353) 021 4901721; Email: RMunuswamy@ucc.ie
    • Sub-Investigator: Gerard Clarke, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Healthy adult volunteers consuming varying amounts of dietary fibre.

Description

Inclusion Criteria:

• Be able to give written informed consent.
• Be between 18 and 50 years of age.
• Have a body mass index (BMI) between 18.5-29.9 Kg/m2.
• Be in generally good health as determined by the investigator.

Exclusion Criteria:

• Are less than 18 and greater than 50 years of age.
• Have a BMI below 18.5 or above 29.9 Kg/m2.
• Have a significant acute or chronic coexisting illness [cardiovascular, gastrointestinal (GI) [to include functional GI disorders, inflammatory bowel disease, coeliac disease, lactose intolerance, food allergies], immunological, psychiatric [to include formal or as determined by MINI Psychiatric interview, diagnosis of current major depression, anxiety disorder, bipolar spectrum disorder, schizophrenia, other DSM-IV Axis I disorder], neurodevelopmental disorders, immunological, metabolic disorders [to include type I or II diabetes], or any condition which contraindicates, in the investigators judgement, entry to the study.
• Have a condition or taking a medication that the investigator believes would interfere with the objectives of the study, pose a safety risk, or confound the interpretation of the study results; all psychoactive medications [to include anxiolytics, antipsychotics, antidepressants, anticonvulsants, centrally acting corticosteroids, and opioid pain relievers), laxatives, enemas, antibiotics, anti-coagulants, over-the counter non-steroidal anti-inflammatories (NSAIDS). Subjects should have a wash-out period of 4 weeks.
• Current prebiotic or probiotic supplement use (a wash-out period of 4 weeks after cessation will allow entry to the study).
• Females who are peri-menopausal, menopausal or post-menopausal.
• Females who are pregnant or planning a pregnancy, or lactating.
• Participants who are not fluent in English.
• Are colour blind.
• Have dyslexia or dyscalculia.
• Are a current habitual daily smoker.
• Individuals who, in the opinion of the investigator, are considered to be poor attendees or unlikely for any reason to be able to comply with the trial.
• Subjects receiving treatment involving experimental drugs. If the subject has been in a recent experimental trial, these must have been completed not less than 30 days prior to this study.
• Have a malignant disease or any concomitant end-stage organ disease.
• Have completed a study in our laboratory in the past 4 years.

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Low fibre consumers; Healthy adults consuming less than or equal to 18 grams of fibre per day.	Other: Dietary fibre; Habitual dietary consumption from a variety of foods will be assessed using 7-day food logs entered by the participant and assessed for accuracy by a dietitian.
Moderate fibre consumers; Healthy adults consuming between 18.1-24.9 grams of fibre per day.	Other: Dietary fibre; Habitual dietary consumption from a variety of foods will be assessed using 7-day food logs entered by the participant and assessed for accuracy by a dietitian.
High fibre consumers; Healthy adults consuming greater than or equal to 25 grams of fibre per day.	Other: Dietary fibre; Habitual dietary consumption from a variety of foods will be assessed using 7-day food logs entered by the participant and assessed for accuracy by a dietitian.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Trait stress/mood: self-report	Self-report questionnaires	Compared at baseline
Trait stress/mood: hypothalamic-pituitary-adrenal axis activity	Cortisol from saliva samples	Compared at baseline
Responses to acute stress: self-report	Self-report questionnaires	Compared at baseline
Responses to acute stress: hypothalamic-pituitary-adrenal axis activity	Cortisol from saliva samples	Compared at baseline
Responses to acute stress: sympathetic-adrenal-medullary pathway activity	Galvanic skin response taken from the skin on the hand	Compared at baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cognitive performance: working memory	Spatial Working Memory	Compared at baseline
Cognitive performance: episodic memory	Modified Rey Auditory Verbal Learning Test (ModRey)	Compared at baseline
Cognitive performance: decision making	Iowa Gambling Task	Compared at baseline
Cognitive performance: emotional inhibition	Emotional stroop	Compared at baseline
Cognitive performance: sustained attention	Rapid Visual Information Processing	Compared at baseline
Cognitive performance: visual pattern recognition memory	Pattern Recognition Memory	Compared at baseline
Cognitive performance: cognitive flexibility	Intra-Extra Dimensional Set Shifting	Compared at baseline
Cognitive performance: social cognition	Emotion Recognition Task	Compared at baseline
Cognitive performance: affective perceptual bias	Emotional Bias Task	Compared at baseline
Microbiota composition and function	Shotgun metagenomics of fecal samples	Compared at baseline
Microbial and host metabolites	Untargeted metabolomics analysis in fecal and urine samples	Compared at baseline
Inflammation	Inflammatory markers in lipopolysaccharide stimulated and unstimulated bloods	Compared at baseline

Collaborators and Investigators

• Sponsor: University College Cork
• Investigators: Principal Investigator: John F Cryan, PhD, APC Microbiome Irealnd

Study record dates

Study Major Dates

• Study Start (Actual): July 14, 2022
• Primary Completion (Estimated): July 1, 2024
• Study Completion (Estimated): July 1, 2024

Study Registration Dates

• First Submitted: June 12, 2023
• First Submitted That Met QC Criteria: June 27, 2023
• First Posted (Actual): July 5, 2023

Study Record Updates

• Last Update Posted (Actual): July 5, 2023
• Last Update Submitted That Met QC Criteria: June 27, 2023
• Last Verified: June 1, 2023

More Information

Terms related to this study

• Keywords: Stress; Diet; Cognition; Dietary fibre; Microbiota-gut-brain axis
• Other Study ID Numbers: APC150a

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No