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Trial registered on ANZCTR

Registration number

ACTRN12622001212741

Ethics application status

Approved

Date submitted

24/08/2022

Date registered

8/09/2022

Date last updated

8/09/2022

Date data sharing statement initially provided

8/09/2022

Type of registration

Prospectively registered

Titles & IDs

Public title

Gut Decisions: The impact of egg consumption on the gut microbiome, inflammation and brain cognition

Scientific title

The impact of daily egg consumption on the gut microbiome, inflammation and brain cognition in healthy adults

Secondary ID [1]

None

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Disturbed gut microbial composition

Impaired cognitive function

Condition category

Condition code

Diet and Nutrition

Other diet and nutrition disorders

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

180 adults will be recruited (90 aged 18-40, and 90 aged over 60). Each age group will be randomised into either the control group or intervention group. The intervention groups will be as follows:
1. 18-40 year old intervention group: required to eat 2 whole eggs a day for 6 weeks
2. Over 60 intervention group: required to eat 2 whole eggs a day for 6 weeks
There will be no restrictions on how the eggs are to be cooked and prepared for consumption.

Adherence will be monitored through weekly phone calls conducted by a researcher (an accredited practicing dietitian) as well as through three 3-day food records conducted at baseline, mid and end of study.

Intervention code [1]

Treatment: Other

Comparator / control treatment

1. 18-40 year old control group: required to avoid eggs completely over 6 weeks
2. over 60 control group: required to avoid eggs completely over 6 weeks

Control participants will be provided with an information sheet about how to avoid eggs, including specifics on egg-containing foods that can be consumed or should be avoided. Generally speaking, foods with low egg content (such as cakes) are okay, but foods with high egg content (such as quiches or pavlovas) will need to be avoided. This resource will be designed by the researchers specifically for this study.

Adherence will be monitored through weekly phone calls conducted by a researcher (an accredited practicing dietitian) as well as through three 3-day food records conducted at baseline, mid and end of study.

Control group

Active

Outcomes

Primary outcome [1]

Gut microbiota variety. Will be measured through DNA analysis of stool samples.

Timepoint [1]

Stool samples taken at baseline (week 1), mid (week 3) and end of study (week 6)

Primary outcome [2]

Brain cognition factor 1: interoception, Will be measured using the Schandry Paradigm (measures interoception, requires participants to measure their own heart rate)

Timepoint [2]

Cognitive tasks will be conducted at the research facility at baseline (week 1) and end of study (week 6).

Primary outcome [3]

Brain cognition factor 2: Decision-making. Will be measured using the Iowa Gambling task (measures decision-making, conducted as a short test on a computer)

Timepoint [3]

Cognitive tasks will be conducted at the research facility at baseline (week 1) and end of study (week 6).

Secondary outcome [1]

Inflammatory markers- cytokines and c-reactive protein. Measured via 12-hour fasting blood samples that will be taken at the research facility by a researcher who is trained in phlebotomy. Will be analysed using V-Plex pro-inflammatory panel 1 human kits.

Timepoint [1]

Measured at pre (week 1), mid (week 3) and end of study (week 6).

Secondary outcome [2]

Plasma choline levels will be measured via 12-hour fasting blood samples that will be taken at the research facility by a researcher who is trained in phlebotomy. Will be analysed using an INDIKO machine.

Timepoint [2]

Measured at baseline (week 1), mid (week 3) and end of study (week 6).

Secondary outcome [3]

Plasma Lipopolyssacharide -binding protein (LPD) will be measured via 12-hour fasting blood samples that will be taken at the research facility by the primary researcher who is trained in phlebotomy. Will be analysed using Hycult Biotech Human ELISA Kit.

Timepoint [3]

Measured at baseline (week 1), mid (week 3) and end of study (week 6).

Secondary outcome [4]

Dietary intake will be measured via 3-day food records at 3 timepoints throughout the study using the mobile phone app, Research Diet Diary created by Xyris. The information will be transferred to the Xyris Software, Foodworks to allow for analysis. This will measure average intake of energy, macronutrients and micronutrients.

Timepoint [4]

Measured at baseline (week 1), mid (week 3) and end of study (week 6).

Secondary outcome [5]

Plasma Trimethalyine N-Oxide (TMAO) levels will be measured via 12-hour fasting blood samples that will be taken at the research facility by a researcher who is trained in phlebotomy. Will be analysed using an INDIKO machine.

Timepoint [5]

Measured at baseline (week 1), mid (week 3) and end of study (week 6).

Secondary outcome [6]

(Primary outcome)- Brain cognition factor 3: Risk-taking. Measured using Balloon-Analogue Risk Test (measures risk-taking, conducted as a short test on a computer)

Timepoint [6]

Cognitive tasks will be conducted at the research facility at baseline (week 1) and end of study (week 6).

Secondary outcome [7]

(Primary outcome)- Brain cognition factor 4: Reaction time. Measured using Deary-Liewald Task (measures reaction-time, conducted as a short test on a computer)

Timepoint [7]

Cognitive tasks will be conducted at the research facility at baseline (week 1) and end of study (week 6).

Eligibility

Key inclusion criteria

Participants will be female or male in a 1:1 ratio and will be within healthy or overweight BMI categories (BMI 18.5-29.9 kg/m2) and weight stable for the last two months (+/- 10%). No contraception intake.

Minimum age

18 Years

Maximum age

No limit

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

No antibiotics in the last 3 months. No history of neurological or psychiatric diseases. No history of diabetes mellitus, renal, hepatic, cardiovascular and respiratory diseases. No food allergy or chronic allergy (defined as requiring daily antihistamines). No use of pre- and/or probiotic supplements during the previous month. For the 18-40 year old participants, no menopause before the age of 40 years.

Study design

Purpose of the study

Diagnosis

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Allocation is not concealed.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data

Intervention assignment

Parallel

Other design features

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

As there is no previous egg human microbiome cognition study, the sample size of n=45 per arm is based on Steenbergen et al., (2015) (a study that used a probiotic dietary intervention to modify gut microbiota and reduced cognitive reactivity to sad mood) using effect size: 0.158, alpha error: 0.05, Power: 0.80, 2 groups, 6 response variables, Critical F=2.6 Considering dropout rate and intervention duration, 10% (5 participants per arm) additional will be adequate.

Statistical analysis of data during the study will be conducted on the IBM SPSS Statistics Software. Statistical analysis will compare all outcomes between the treatment groups (eggs vs. no eggs) and between population groups (younger vs. older). Correlation between microbial abundance and other outcome measures will be performed. A variance-covariance model will assess for any treatment-by-population-by-time main or interaction effects for microbial abundance and decision-making response. Adjustment for changes in the baseline values of biomarker parameters and BMI will be performed by analysis of covariance (ANCOVA) using general linear models. If normal distribution is violated for the dependent variables under consideration, a linear mixed model will be used.

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

28/11/2022

Actual

Date of last participant enrolment

Anticipated

30/10/2023

Actual

Date of last data collection

Anticipated

11/12/2023

Actual

Sample size

Target

180

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

VIC

Recruitment postcode(s) [1]

3168 - Clayton

Recruitment postcode(s) [2]

3000 - Melbourne

Recruitment postcode(s) [3]

3083 - Bundoora

Funding & Sponsors

Funding source category [1]

Commercial sector/Industry

Name [1]

Australian Eggs

Address [1]

Suite 602, Level 6, 132 Arthur Street
North Sydney NSW 2060
Australia

Country [1]

Australia

Primary sponsor type

Individual

Name

Dr Jessica Biesierkierski

Address

Monash University BASE Facility, 264 Ferntree Gully Rd.,
Notting Hill VIC 3168
Australia

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Monash University Human Research Ethics Committee (MUHREC)

Ethics committee address [1]

Monash University
Wellington Road
Clayton
Victoria 3800
Australia

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

10/08/2022

Approval date [1]

15/08/2022

Ethics approval number [1]

34637

Summary

Brief summary

Eggs provide an affordable, digestible and accessible source of many nutrients, including all eleven essential amino acids, vitamin A, E and B12, selenium, choline and iron, and unsaturated fatty acids including omega-3 (primarily DHA and ALA). Egg yolks are also
high in cholesterol and are a major source of dietary cholesterol in Australia. There are current gaps in the research supporting egg intake and other associated health effects outside of plasma cholesterol levels, across different populations and age groups.
Egg consumption microbiome studies in humans are extremely limited and have previously only focused on overweight postmenopausal women and/or effects on acute plasma choline levels and microbial taxa related to cardiovascular disease. The gut microbiome is thought to be a key component in Trimethylamine N-oxide (TMAO) metabolism, as trimethylamine is produced by gut bacteria from dietary choline, betaine, or L-carnitine, and then converted in the liver to TMAO, which in turn affects hepatic and intestinal lipid metabolism. Previous human studies have not shown egg consumption to affect plasma TMAO concentrations. However, inter-individual differences highlight the need for larger cohorts and more comprehensive assessment of the effects of egg consumption on gut microbiota.
The overall aim is to examine the human gut microbiome in response to egg consumption (compared to no egg consumption) and explore other clinical outcomes (i.e., cognition) and potential mediating factors (i.e., inflammation regulation) in younger and older adults.
Specifically, the aims are:
1. To assess effects of 6 weeks’ egg consumption on gut microbial composition and how consequent shifts in gut microbiome species and community function differ between age groups.
2. To explore how egg consumption may influence intuitive decision making, interoception, risk-taking and reaction-time
3. To explore how egg consumption may modulate intestinal immunity by altering levels of anti-inflammatory cytokines and other inflammatory markers such as C-reactive protein. 
4. To explore the relationship between regular egg consumption,  plasma choline, lipo-polysaccharide binding protein, and TMAO and how these levels may modulate or influence any of the above endpoints.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Jessica Biesierkiersi

Address

Monash BASE Facility, 264 Ferntree Gully Rd.
Notting Hill VIC 3168

Country

Australia

Phone

+61 3 9902 4269

Fax

jessica.biesiekierski@monash.edu

Contact person for public queries

Name

Jessica Biesierkiersi

Address

Monash BASE Facility, 264 Ferntree Gully Rd.
Notting Hill VIC 3168

Country

Australia

Phone

+61 3 9902 4269

Fax

jessica.biesiekierski@monash.edu

Contact person for scientific queries

Name

Jessica Biesierkiersi

Address

Monash BASE Facility, 264 Ferntree Gully Rd.
Notting Hill VIC 3168

Country

Australia

Phone

+61 3 9902 4269

Fax

jessica.biesiekierski@monash.edu

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

Reasonable requests for access to the original de-identified data will be considered on a case-by-case basis by the Funding Body (Australian Eggs).

When will data be available (start and end dates)?

Data may be available up to 5 years after study completion (anticipated 2024).

Available to whom?

Reasonable requests for access to the original de-identified data will be considered on a case-by-case basis by the Funding Body (Australian Eggs).

Available for what types of analyses?

Reasonable requests for access to the original de-identified data will be considered on a case-by-case basis by the Funding Body (Australian Eggs).

How or where can data be obtained?

The funding body, Australian Eggs, can be contacted at contacts@australianeggs.org.au for any requests to access data.

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

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No documents have been uploaded by study researchers.

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No additional documents have been identified.

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