COVID-19 studies are our top priority. For all other trials, there is a 4-week delay in processing a trial submitted/resubmitted to the ANZCTR and additional delays for updates of registered trials. We appreciate your patience.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of cocoa on cognitive function
Scientific title
The acute effect and dose-response of a high-flavanol cocoa product on cognitive function and mood in middle aged adults
Secondary ID [1] 286292 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cognition 294376 0
Mental fatigue 294474 0
Condition category
Condition code
Neurological 294694 294694 0 0
Studies of the normal brain and nervous system
Mental Health 294780 294780 0 0
Studies of normal psychology, cognitive function and behaviour
Alternative and Complementary Medicine 294781 294781 0 0
Herbal remedies

Study type
Description of intervention(s) / exposure
This randomised double-blind placebo-controlled trial will test the acute effect and dose-response of 2 doses of cocoa (Dose 1: 2 tablets: 6116 mg Theobroma cacao seed extract standardised to 500 mg catechins polyphenols and 11.12 mg theobromine; Dose 2: 4 tablets containing 1g of catechins polyphenols and 22.24 mg theobromine) compared to flavanols-free placebo on cognition using the computerised SUCCAB test battery in a middle aged population in the NIIM cognitive function lab. On Day 1, after baseline assessment cocoa or placebo tablets will be given to participants, and cognition will be tested on 2 hours after ingestion of the trial tablets. Cognitive assessment will be repeated 4 weeks later on the same participants using a different dose of cocoa.
Intervention code [1] 291329 0
Treatment: Other
Comparator / control treatment
Placebo: flavanol-free cellulose-silica tablet
Control group

Primary outcome [1] 294454 0
cognitive function using the computerised validated SUCCAB test battery (Swinburne University Computerised Cognitive Assessment Battery)
Timepoint [1] 294454 0
2 hours after intervention
Secondary outcome [1] 313359 0
Composite: mood and mental fatigue using the validated Spielberger State Anxiety Trait Inventory and the the Bond-Lader Visual Analogue Mood Scale
Timepoint [1] 313359 0
2 hours after intervention

Key inclusion criteria
- Adults 40-70 years
- Have a good working knowledge of English

Minimum age
40 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- Colour blind
- Currently suffering from medically diagnosed cardiovascular or cognitive impairment, psychiatric or neurological conditions
- Taking any cognitive enhancing medications or herbal supplements or illicit drugs
- Taking antidepressants, antipsychotics or anxiolytics
- Taking anti-coagulants or have bleeding disorders
- Pregnant or lactating
- Participating in any other study

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Recruitment: In the first instance we will contact past trial participants, who agreed to be contacted again to be invited to participate in a trial at NIIM. In addition, we will distribute flyers in letterboxes in the local area, as this recruitment strategy has worked well in the last trial (30% of participants had been recruited through letterbox drop).
Allocation: Cocoa tablets and placebo tablets will be matched in colour, size, and number (Dose 1 = 2 tablets; Dose 2 = 4 tablets), and packaged in identical containers labelled consecutively.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisations will be conducted using a computer-generated random number table by an independent researcher not involved in data collection. We will undertake two randomisations: Randomisation 1: Participants will be randomly allocated to either dose 1 or placebo on day 1; Randomisation 2: Participants will be randomly allocated to either dose 2 or placebo on day 28
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Parallel design in part 1 (randomisation 1, dose 1 on day 1);
parallel design in part 2 (randomisation 2, dose 2, on day 28) with same participants as in part 1
Two time points will be analysed independently
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Primary outcome will be cognitive function in accuracy and speed using the SUCCAB test battery (30 minutes) at 2 hours after ingestion of cocoa tablets (Dose 1) or placebo on Day 1, and at 4 weeks ingestion of cocoa tablets (Dose 2) compared to baseline. Cocoa tablets will be analysed for flavanols and theobromine content.
Secondary outcome will be assessment of mood, mental fatigue, and stress using the Bond-Lader Visual Analogue Mood Scale and the Spielberger State Anxiety Trait Inventory (STAIT) before and after each testing session.
All comparisons will be made using ANOVA and t-tests.

A sample size of 40 participants (20 in each group in part 1 and in part 2) was calculated based on the following assumptions:
a) To detect a difference of 57 ± 90 msec in the working memory reaction time test of the SUCCAB test battery with a power of 80% and 95% confidence (Macpherson H et al Psychopharmacology 2012, 220: 351-365)

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 9325 0
3122 - Hawthorn West

Funding & Sponsors
Funding source category [1] 290858 0
Self funded/Unfunded
Name [1] 290858 0
Address [1] 290858 0
Country [1] 290858 0
Primary sponsor type
National Institute of Integrative Medicine
21 Burwood Rd, Hawthorn, VIC 3122
Secondary sponsor category [1] 289550 0
Name [1] 289550 0
Address [1] 289550 0
Country [1] 289550 0
Other collaborator category [1] 278377 0
Name [1] 278377 0
A/Prof Andrew Pipingas
Address [1] 278377 0
Centre for Human Psychopharmacology
Swinburne University
PO Box 218
Hawthorn, VIC 3122
Country [1] 278377 0

Ethics approval
Ethics application status
Ethics committee name [1] 292474 0
Ethics committee address [1] 292474 0
National Institute of Integrative Medicine
21 Burwood Rd, Hawthorn, VIC 3122
Ethics committee country [1] 292474 0
Date submitted for ethics approval [1] 292474 0
Approval date [1] 292474 0
Ethics approval number [1] 292474 0

Brief summary
Cocoa flavanols have been associated with several health benefits including cardiovascular and cognitive functions. Cocoa flavanols increase the formation of endothelial nitric oxide, responsible for the increased blood flow and improved cardiovascular and vascular function.

A small number of studies have tested the acute effect of cocoa on cognitive function, demonstrating benefits on alertness, fatigue, and mood using a cognitively demanding test in a population of young students. While early studies used high-flavanol cocoa powder compared with low-flavanol powder as control, a truly double-blind design using cocoa versus non-flavanol containing placebo tablets have been tested in a previous study undertaken by this team, eliminating potential confounding of low-dose flavanol products.
While the team's previous study tested a population of young students (mean age = 23 years), the proposed project aims to explore an older population (mean age = 60 years) using the Swinburne University Computerised Cognitive Assessment Battery (SUCCAB) test, assessing speed and accuracy, which has been shown to correlate to cognitive decline through ageing.
the study will test the hypothesis whether an acute dose of cocoa improves cognitive function in a middle aged population.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 55454 0
Dr Karin Ried
Address 55454 0
National Institute of Integrative Medicine
21 Burwood Rd, Hawthorn, VIC 3122
Country 55454 0
Phone 55454 0
+61 3 9912 9545
Fax 55454 0
Email 55454 0
Contact person for public queries
Name 55455 0
Dr Karin Ried
Address 55455 0
National Institute of Integrative Medicine
21 Burwood Rd, Hawthorn, VIC 3122
Country 55455 0
Phone 55455 0
+61 3 9912 9545
Fax 55455 0
Email 55455 0
Contact person for scientific queries
Name 55456 0
Dr Karin Ried
Address 55456 0
National Institute of Integrative Medicine
21 Burwood Rd, Hawthorn, VIC 3122
Country 55456 0
Phone 55456 0
+61 3 9912 9545
Fax 55456 0
Email 55456 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary