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Trial registered on ANZCTR


Registration number
ACTRN12624000983505
Ethics application status
Approved
Date submitted
17/06/2024
Date registered
13/08/2024
Date last updated
13/08/2024
Date data sharing statement initially provided
13/08/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
A whole-food diet and obsessive-compulsive disorder: a pilot study
Scientific title
Evaluating the Impact of Two Whole-Food Diets on Obsessive-Compulsive Disorder in Adults: A Multiple Baseline Pilot Study
Secondary ID [1] 312195 0
None
Universal Trial Number (UTN)
U1111-1309-1995
Trial acronym
NOURISH-OCD
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obsessive-compulsive disorder 333862 0
Anxiety 333863 0
Condition category
Condition code
Mental Health 330538 330538 0 0
Anxiety

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Upon entering the study, all participants will be randomly allocated into one of three baseline conditions - 1, 2 or 3 weeks. During these periods, participants will be eating their usual diets and will all be asked to have a blood test to measure for various markers of metabolic health, as well as vitamins and minerals. At the conclusion of the baseline period, all participants will then enter a one-week 'logistics week', in which they will receive materials which will outline all they need to know about the dietary intervention they are about to commence at the end of the logistics week, providing them time to prepare. Therefore, they will be required to go shopping for the necessary foods that will fit within the dietary interventions. There are two dietary interventions that will be used in this study; The Whole Diet, and The Whole Plus Diet. All participants will commence the first dietary intervention, The Whole Diet, for eight-weeks. At the end of this eight-weeks, if participants haven't experienced a clinically significant reduction in their OCD symptoms, they will continue to The Whole Plus Diet for a further eight-weeks. This will be determined by a clinician-rated outcome psychometric as well as the YBOCS score, which will be obtained from the 8-week check in at the end of the first dietary intervention. For those who do experience a clinically significant improvement in their OCD symptoms, they will conclude the trial after finishing The Whole Diet.

The two dietary interventions are outlined below:

The Whole Diet
The Whole Diet is a whole-foods diet which centres on the removal of ultra-processed foods (UPF) from the diet. In this study, UPF will be defined using the NOVA classification system, which groups foods into four groups based on their level of industrial process (Carlos Augusto Monteiro, Levy, Claro, Castro, & Cannon, 2010). These four groups are unprocessed and minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods (Monteiro et al., 2019). Ultra-processed food is defined as being industrial formulations which contain minimal to no whole food, such as chocolate, confectionary, ice-cream and soft drinks (Carlos A Monteiro et al., 2019). UPF are hyper-profitable, hyperpalatable (through the use of additives and flavours), have an extensive marketing budget, and are thus suggested to displace whole food consumption (Carlos A Monteiro et al., 2019).

The Whole Plus Diet
The Whole Plus Diet is a whole foods anti-inflammatory diet that removes common inflammatory foods including gluten and dairy (Asoudeh et al., 2023; De Punder & Pruimboom, 2013; Junker et al., 2012), as well as alcohol, caffeine, additives and refined sugar. This dietary pattern encourages unlimited consumption of whole foods (with an emphasis on diversity) of fruits, vegetables, meats, legumes, non-gluten containing grains, healthy fats, fermented foods, and herbs and spices. The Whole Plus Diet also allows ‘healthy treats’ including dark chocolate, honey and maple syrup.

This diet is a modified Paleo diet (Cordain, 2002), and is based on the principles of the NOVA classification group one (whole, unprocessed foods) (Carlos Augusto Monteiro et al., 2010). It is also supported by research that has explored biological mechanisms that underpin the pathogenesis of OCD and other psychopathologies including inflammation (Gerentes, Pelissolo, Rajagopal, Tamouza, & Hamdani, 2019), metabolic health (Khalkhali, Rasekh, Eslamdoust-Siahestalkhi, Farrahi, & Zare, 2023) and gut dysbiosis (Turna et al., 2020) and foods that can promote these pathways. Research exploring OCD has indicated that the removal of gluten (Rodrigo et al., 2018) and foods high in free glutamate (Holton & Cotter, 2018) could be beneficial.

Adherence to dietary intervention will be monitored by the participant being prompted 3-times weekly to send in a day of photos of their food, AI will be utilised to support us in determining the level of adherence. They will also complete two measures of self-efficacy for adherence to the diet.
Intervention code [1] 328640 0
Treatment: Other
Comparator / control treatment
Participants will be acting as their own controls in this single-case design study.
Control group
Active

Outcomes
Primary outcome [1] 338302 0
Obsessive-compulsive disorder symptoms
Timepoint [1] 338302 0
At consent (prior to baseline), weeks 4 (half way through the first dietary intervention), 8 (the end of the first dietary intervention), 12 (half way through second dietary intervention), 16 (end of second dietary intervention) and 6-month follow up (6-months from the end of where the participant concluded the dietary intervention)
Primary outcome [2] 338303 0
Obsessive-compulsive disorder symptoms
Timepoint [2] 338303 0
Baseline, and then each week the participant is in the study (this is a self-report screening tool)
Primary outcome [3] 338304 0
Patient's overall functioning
Timepoint [3] 338304 0
weeks 4 (half way through the first dietary intervention), 8 (the end of the first dietary intervention), 12 (half way through second dietary intervention), 16 (end of second dietary intervention) and 6-month follow up (6-months from the end of where the participant concluded the dietary intervention)
Secondary outcome [1] 435362 0
Ultra-processed food intake
Timepoint [1] 435362 0
Baseline, every week participant is in intervention, and 6-month follow up
Secondary outcome [2] 435363 0
Gastrointestinal symptoms
Timepoint [2] 435363 0
Baseline, each week participant is in intervention, and 6-month follow up
Secondary outcome [3] 435364 0
Anxiety
Timepoint [3] 435364 0
Baseline, every week participant is in intervention, and 6-month follow up
Secondary outcome [4] 435365 0
Depression
Timepoint [4] 435365 0
Baseline, every week participant is in intervention, and 6-month follow up
Secondary outcome [5] 435366 0
Symptom severity
Timepoint [5] 435366 0
At baseline (prior to the commencement of the dietary intervention), weeks 4 (half way through the first dietary intervention), 8 (the end of the first dietary intervention), 12 (half way through second dietary intervention), 16 (end of second dietary intervention) and 6-month follow up (6-months from the end of where the participant concluded the dietary intervention)
Secondary outcome [6] 435367 0
Risk
Timepoint [6] 435367 0
At baseline (prior to the commencement of the dietary intervention), weeks 4 (half way through the first dietary intervention), 8 (the end of the first dietary intervention), 12 (half way through second dietary intervention), 16 (end of second dietary intervention) and 6-month follow up (6-months from the end of where the participant concluded the dietary intervention)
Secondary outcome [7] 435368 0
Quality of life
Timepoint [7] 435368 0
Baseline, each week participant is in intervention, and 6-month follow up
Secondary outcome [8] 435369 0
Self-efficacy with regards to diet
Timepoint [8] 435369 0
Each week participant is in intervention, and 6-month follow up
Secondary outcome [9] 435370 0
Adherence to diet
Timepoint [9] 435370 0
Each week participant is in intervention, and 6-month follow up
Secondary outcome [10] 435371 0
Vitamin B12
Timepoint [10] 435371 0
Baseline and week 8 (end of first dietary intervention)
Secondary outcome [11] 437897 0
Anxiety
Timepoint [11] 437897 0
At baseline (prior to the commencement of the dietary intervention), weeks 4 (half way through the first dietary intervention), 8 (the end of the first dietary intervention), 12 (half way through second dietary intervention), 16 (and of second dietary intervention) and 6-month follow up (6-months from the end of where the participant concluded the dietary intervention)
Secondary outcome [12] 437898 0
Stress
Timepoint [12] 437898 0
At baseline (prior to the commencement of the dietary intervention), weeks 4 (half way through the first dietary intervention), 8 (the end of the first dietary intervention), 12 (half way through second dietary intervention), 16 (and of second dietary intervention) and 6-month follow up (6-months from the end of where the participant concluded the dietary intervention)
Secondary outcome [13] 437899 0
Folate
Timepoint [13] 437899 0
Baseline and week 8 (end of first dietary intervention)
Secondary outcome [14] 437900 0
Cortisol
Timepoint [14] 437900 0
Baseline and week 8 (end of first dietary intervention)
Secondary outcome [15] 437901 0
Vitamin D
Timepoint [15] 437901 0
Baseline and week 8 (end of first dietary intervention)
Secondary outcome [16] 437902 0
HbA1c
Timepoint [16] 437902 0
Baseline and week 8 (end of first dietary intervention)
Secondary outcome [17] 437903 0
Homocysteine
Timepoint [17] 437903 0
Baseline and week 8 (end of first dietary intervention)

Eligibility
Key inclusion criteria
Participants must be aged 18 years and over, and have a diagnosis of OCD from a medical doctor, psychologist or psychiatrist. Participants will also be required to score greater than or equal to 16 on the Yale Brown Obsessive Compulsive Scale (YBOCS), indicating moderate to severe symptoms of OCD. As the study is recruiting participants from all over New Zealand and will be run virtually, it is imperative that all participants have internet access.

Participants will be asked not to make any new treatment or any new lifestyle changes over the course of the study. This would include starting psychological treatment/ counselling, new exercise habits and/or other dietary changes aside from the ones recommended within this study.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Participants will be excluded from the study if they have a diagnosis of any of the following psychiatric conditions: personality disorders, eating disorders, schizophrenia spectrum and other psychotic disorders, bipolar disorder, or a substance abuse disorder. These conditions have been excluded due to their potential of disrupting participant compliance.

Participants will also be excluded from the study if they are unwilling to make dietary changes or unwilling to attend follow up appointments. If participants are currently receiving psychological therapy, they will be advised that they can take part in the trial once their therapy has concluded. Participants are able to take part in this study if they are currently taking psychiatric medications; however, it is important that they have been taking these for at least 6 months prior to commencing the trial.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Descriptive statistics of means, medians, standard deviations and ranges of primary and secondary outcome measures will be presented in a table to examine measures over all time points. Correlational analyses (r) will be used to examine relationships between primary and secondary measures across selected time points. Modified Brinley plots will be used as a graphic analysis of participants’ treatment response over various time points (Blampied, 2017).

To detect an effect of dietary intervention on symptoms of OCD, a repeated measures (within-groups) analysis of variance (ANOVA) will be used to assess changes in OCD symptom severity across different time periods within each dietary intervention. In order to quantify the impact of each dietary intervention, effect sizes will be calculated using Cohen’s d and the Common Language Effect Size (CLES).

Time series graphs of multiple non-concurrent baseline data and YBOCS scoring will be used to examine both individual differences and group differences between the three different baseline conditions (1-, 2-, and 3-week baseline conditions), and will be analysed using visual analysis. This will allow for the examination of a possible causal process (Cooper, Heron, & Heward, 2020).

Qualitative analysis through participant survey responses will be used to capture participant experience of their adherence to the dietary interventions they engaged with.

The above analyses will be carried out using Excel and Jamovi.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
31/08/2024
Actual
Date of last participant enrolment
Anticipated
2/05/2025
Actual
Date of last data collection
Anticipated
1/03/2026
Actual
Sample size
Target
45
Accrual to date
Final
Recruitment outside Australia
Country [1] 26321 0
New Zealand
State/province [1] 26321 0

Funding & Sponsors
Funding source category [1] 316570 0
University
Name [1] 316570 0
University of Canterbury
Country [1] 316570 0
New Zealand
Funding source category [2] 316572 0
Charities/Societies/Foundations
Name [2] 316572 0
The Gut Foundation
Country [2] 316572 0
New Zealand
Primary sponsor type
Individual
Name
Sophia Dawson
Address
Country
New Zealand
Secondary sponsor category [1] 318748 0
Individual
Name [1] 318748 0
Professor Julia Rucklidge
Address [1] 318748 0
Country [1] 318748 0
New Zealand
Secondary sponsor category [2] 319295 0
Individual
Name [2] 319295 0
Professor Grant Schofield
Address [2] 319295 0
Country [2] 319295 0
New Zealand
Other collaborator category [1] 283047 0
Individual
Name [1] 283047 0
Emeritus Professor Neville Blampied
Address [1] 283047 0
Country [1] 283047 0
New Zealand
Other collaborator category [2] 283048 0
Individual
Name [2] 283048 0
Provost Associate Professor Katie Holton
Address [2] 283048 0
Country [2] 283048 0
United States of America

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315357 0
Central Health and Disability Ethics Committee
Ethics committee address [1] 315357 0
https://ethics.health.govt.nz/about/central-health-and-disability-ethics-committee/
Ethics committee country [1] 315357 0
New Zealand
Date submitted for ethics approval [1] 315357 0
22/05/2024
Approval date [1] 315357 0
10/06/2024
Ethics approval number [1] 315357 0

Summary
Brief summary
The study intends to explore the use of dietary intervention in the management of obsessive-compulsive disorder (OCD). This study uses a non-concurrent multiple baseline design, randomising participants into one of three baseline lengths. There will be a stepped-care approach to the delivery of two dietary interventions; The Whole Diet and The Whole Plus Diet, implemented for 8-weeks each. If participants achieve a clinically significant improvement to their OCD symptoms at the end of the first intervention, The Whole Diet, they will conclude the trial. Those who do not note such improvements will continue to The Whole Plus Diet. It is hypothesized that the dietary interventions used within this study will reduce OCD symptom severity to a clinically meaningful degree, and that participants will be able to meaningfully adhere to both interventions. In terms of diet quality, it is hypothesized that upon entering the trial, participants will be observed to have a diet that is high in ultra-processed foods.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 134446 0
Ms Sophia Dawson
Address 134446 0
University of Canterbury, 20 Kirkwood Road, Christchurch, Canterbury 8140
Country 134446 0
New Zealand
Phone 134446 0
+6421619557
Fax 134446 0
Email 134446 0
[email protected]
Contact person for public queries
Name 134447 0
Sophia Dawson
Address 134447 0
University of Canterbury, 20 Kirkwood Road, Christchurch, Canterbury 8140
Country 134447 0
New Zealand
Phone 134447 0
+6421619557
Fax 134447 0
Email 134447 0
[email protected]
Contact person for scientific queries
Name 134448 0
Julia Rucklidge
Address 134448 0
University of Canterbury, 20 Kirkwood Road, Christchurch, Canterbury 8140
Country 134448 0
New Zealand
Phone 134448 0
+64336994398
Fax 134448 0
Email 134448 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Participants in this trial have not consented to their data being shared in such a way.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

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No additional documents have been identified.