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Trial registered on ANZCTR


Registration number
ACTRN12624000020583
Ethics application status
Approved
Date submitted
4/12/2023
Date registered
11/01/2024
Date last updated
11/01/2024
Date data sharing statement initially provided
11/01/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of hops on neurotransmitter concentrations in blood.
Scientific title
The acute effect of consuming hops extract in modulating plasma neurotransmitter concentrations in healthy adults.
Secondary ID [1] 311093 0
Nil
Universal Trial Number (UTN)
U1111-1301-1092
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Neurotransmitter modulation 332248 0
Condition category
Condition code
Neurological 328963 328963 0 0
Studies of the normal brain and nervous system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This study will investigate the effect hops and isomerised (iso) hops on circulating neurotransmitter concentrations. We will implement a randomised, placebo-controlled, repeated measures study design. Prospective participants who have passed the study’s inclusion/exclusion criteria will be asked to attend a familiarisation session where they will meet with the study’s principal investigator. During this session the study’s trial coordinator (Research Associate, approx. 6 years experience in human studies) or the principal investigator (Research Scientist, PhD) will explain the logistics of the trial to them and answer any questions they may have.

Enrolled participants (n = 8) will attend a total of five trial days. Participants will be given a list of foods (e.g. hops and hops-containing foods and supplements) to abstain from consuming 24 hours prior each trial day. Participants will be also be asked to refrain from eating any food or drink (other than water) 10 h before the start of their scheduled trial day except for their supplied breakfast (one Almond One Square Meal bar [Cookie Time Ltd.]) that will be provided for them to consume approximately 2 h before your scheduled arrival at the research facility for their trial day. Upon arriving at the research facility, a venous blood sample (approximately 9 mL) will be collected from them. They will then be given a single serve of their allocated intervention (hops or isomerised hops (125 and 250 mg a-acids) or placebo) to consume as quickly as they can. After this, they will be directed to the seating area of the facility to wait. Two hours and 4 h after consuming their allocated intervention, 9 mL of venous blood will be collected from them. After the 4 h blood sample collection is finished, they will be offered a small snack to eat before you leave the facility. After their first trial day, participants will be required to return to the facility for four more trial days with at least five days washout period between trial days.

Hops and isohops extract will be commercially sourced and prepared in a food safe facility. Doses used in this study have been used in previous used in nutritional interventions. All hops interventions will be suspended in food grade canola oil and encapsulated in gelatine capsules and consumed with water. The placebo capsules will be matched to contain the same amount of canola oil and water as the hops and isohops interventions.
Intervention code [1] 327543 0
Treatment: Other
Comparator / control treatment
The placebo capsules will be matched to contain the same amount of canola oil and water as the hops and isohops interventions. The appearance of the placebo will also as similar as possible to the hops and isohops interventions.
Control group
Placebo

Outcomes
Primary outcome [1] 336757 0
Composite measure of plasma neurotransmitter concentrations.
Timepoint [1] 336757 0
0 h (baseline), 2 h (primary timepoint) and 4 h post intervention consumption.
Primary outcome [2] 336758 0
Plasma prolactin concentration
Timepoint [2] 336758 0
0 h (baseline), 2 h (primary timepoint) and 4 h post intervention consumption.
Secondary outcome [1] 429600 0
Heart rate variation
Timepoint [1] 429600 0
Continuously measured over the duration of the trial day.
Secondary outcome [2] 429601 0
Composite measure of bioavailabile hops compounds in blood plasma
Timepoint [2] 429601 0
0 h (baseline), 2 h (primary timepoint) and 4 h post intervention consumption.

Eligibility
Key inclusion criteria
Healthy individual (male or female) 18 – 50 years who are able to provide written consent to participate when selected for this study, are non-smokers and vapers and are not prescribed psychotropic medication or MAO inhibitors.
Minimum age
18 Years
Maximum age
50 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants will be excluded if they are unwilling to unable to provide written consent or comply with the study procedures. Participants will be excluded if they are pregnant, planning to get pregnant in the immediate future or have any of the following conditions: (i) blood borne diseases (e.g. hepatitis), (ii) recent bacterial or viral illness, (iii) are taking medication that affects the properties of blood (e.g. blood clotting) or immune function, (iv) are taking medication for mental health and mood disorders, (v) have a strong fear or dislike of needles and/or the sight of blood, have an aversion to blood sampling, or difficult veins to access.

Participants will also be excluded if they have known hypersensitivity or intolerance to hops or hops derived food products.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The randomisation of participants will be undertaken by a fellow scientist not involved in this study using a computer randomisation function. All recruited participants will then be allocated a random participant code (consisting of numerical and alphabetical characters) containing no information on which order of treatment they were allocated to. To conceal the treatment allocation from the study investigators, those preparing and packaging the treatment interventions for the participants will not be involved in any other component of the study. Further, the constituents for the placebo of the hops interventions will be commercially sourced and will be prepared to be as close as possible in appearance and to the hops interventions. The hops interventions will be served in an opaque envelope to the participants. These measures will be taken to conceal the identity of the interventions to the volunteers and study investigators
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation of treatment intervention will be conducted by simple randomisation using a randomisation table created by computer software (i.e., randomisation function of Microsoft Excel).
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
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
29/01/2024
Actual
Date of last participant enrolment
Anticipated
29/03/2024
Actual
Date of last data collection
Anticipated
26/04/2024
Actual
Sample size
Target
8
Accrual to date
Final
Recruitment outside Australia
Country [1] 26010 0
New Zealand
State/province [1] 26010 0
Auckland

Funding & Sponsors
Funding source category [1] 315352 0
Government body
Name [1] 315352 0
The New Zealand Institute for Plant and Food Research Limited
Country [1] 315352 0
New Zealand
Primary sponsor type
Individual
Name
Dr Jocelyn Eason
Address
The New Zealand Institute for Plant & Food Research, Batchelar Road Fitzherbert Palmerston North 4474
Country
New Zealand
Secondary sponsor category [1] 317412 0
None
Name [1] 317412 0
Address [1] 317412 0
Country [1] 317412 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 314271 0
Northern B Health and Disability Ethics Committees
Ethics committee address [1] 314271 0
Ministry of Health Health and Disability Ethics Committees, 133 Molesworth Street, Wellington 6140.
Ethics committee country [1] 314271 0
New Zealand
Date submitted for ethics approval [1] 314271 0
08/12/2023
Approval date [1] 314271 0
19/12/2023
Ethics approval number [1] 314271 0

Summary
Brief summary
The regulation of neurotransmitter action by dietary compounds provides an avenue to improve general brain wellness and cognitive function of individuals undergoing increased mental stress/challenges. Dietary compounds may regulate neurotransmitter concentrations via several mechanisms, including the direct stimulation on neurotransmitter release. Randomised, placebo-controlled studies have reported that supplementation with hops and hops derived compounds has been shown to increase the blood concentrations of neurotransmitter stimulatory hormones and to acutely affect cognitive performance in people. Hops increased the levels of gut hormones CCK and GLP-1 that affect mood and cognition, in part by the stimulation of pro-cognitive neuropeptides via the activation of the vagus nerve, and hops bitter acid derived compounds improve cognition after both acute and chronic supplementation (Ayabe et al. 2020). However, the minimum dose of efficacy by which hops-derived bitter compounds stimulate pro-cognitive neurotransmitters has not been characterised.

The objective of this project is to determine the effect of NZ hops on circulating neurotransmitter concentrations, changes in heart rate variation, and bioavailability of hops compounds after a single dose of four different hops interventions.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 131006 0
Dr Dominic Lomiwes
Address 131006 0
The New Zealand Institute for Plant & Food Research Ltd., Batchelar Road, Private Bag 11600, Palmerston North 4442
Country 131006 0
New Zealand
Phone 131006 0
+6463556231
Fax 131006 0
Email 131006 0
[email protected]
Contact person for public queries
Name 131007 0
Pramod Gopal
Address 131007 0
The New Zealand Institute for Plant & Food Research Ltd., Batchelar Road, Private Bag 11600, Palmerston North 4442
Country 131007 0
New Zealand
Phone 131007 0
+64 6 953 7678
Fax 131007 0
Email 131007 0
[email protected]
Contact person for scientific queries
Name 131008 0
Dominic Lomiwes
Address 131008 0
The New Zealand Institute for Plant & Food Research Ltd., Batchelar Road, Private Bag 11600, Palmerston North 4442
Country 131008 0
New Zealand
Phone 131008 0
+6463556231
Fax 131008 0
Email 131008 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
Given the potential commercial potential of this work, publicly disclosing individual participant data risks our organisation disclosing intellectual property generated from this study. Furthermore, ethics guidelines for human clinical studies do not allow us to release data that may risk the disclosure of the identity of participants who took part in this study.


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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