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Trial registered on ANZCTR


Registration number
ACTRN12620000005954
Ethics application status
Approved
Date submitted
22/11/2019
Date registered
8/01/2020
Date last updated
8/01/2020
Date data sharing statement initially provided
8/01/2020
Type of registration
Retrospectively registered

Titles & IDs
Public title
Dose-response relationship of dietary nitrate-rich beetroot juice on cardiovascular and cognition function in older adults.
Scientific title
Dose-response relationship of dietary nitrate-rich beetroot juice on cardiovascular and cognition function in older adults.
Secondary ID [1] 299875 0
None
Universal Trial Number (UTN)
Trial acronym
TBJP (The Beetroot Juice Project)
Linked study record

Health condition
Health condition(s) or problem(s) studied:
High Blood Pressure 315290 0
Cognitive decline 315291 0
Condition category
Condition code
Cardiovascular 313592 313592 0 0
Hypertension
Cardiovascular 313593 313593 0 0
Coronary heart disease
Neurological 313594 313594 0 0
Other neurological disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The participants had five visits (one familiarisation and four supplementation trials) One bottle (250ml) of nitrate-rich beetroot juice high dose (10.5 mmol nitrate), medium dose (5 mmol nitrate), or low dose (2.5 mmol nitrate) consumed acutely 2.25 hours prior to repeating testing. Each participant consumed all drinks (one per supplementation trial) in a randomised crossover design
Intervention adherence will be controlled for by observing participants consume the drink in the laboratory
Washout period between trials was one week
Intervention code [1] 316151 0
Treatment: Other
Comparator / control treatment
One bottle (250ml) of nitrate-depleted beetroot juice (1 mmol nitrate) consumed acutely 2.25 hours prior to repeating testing. This will be done in a double-blind crossover fashion.
Intervention adherence will be controlled for by observing participants consume the drink in the laboratory
Control group
Placebo

Outcomes
Primary outcome [1] 322051 0
Cardiovascular function (change in mean arterial pressure and systemic vascular resistance via USCOM)
composite outcome
Timepoint [1] 322051 0
Before versus 2.25 hours after consumption of drink
Primary outcome [2] 322052 0
Cognitive function (Cognitive testing and functional near-infrared spectroscopy) cognitive testing included the Corsi block tapering test, rapid visual information processing test, and the Stroop test.
Composite outcome
Timepoint [2] 322052 0
Before versus 2.25 hours after consumption of drink
Primary outcome [3] 322053 0
Blood Pressure (deluxe HEM-7130; OMRON automatic blood pressure machine)
Timepoint [3] 322053 0
Before versus 2.25 hours after consumption of drink
Secondary outcome [1] 377155 0
Resting metabolic rate (using COSMED gas analysis)
Timepoint [1] 377155 0
Before versus 2.25 hours after consumption of drink
Secondary outcome [2] 377156 0
Mood (mood scales; the profile of mood states, feeling scale and felt arousal scale will be used for mood)
Composite Outcome
Timepoint [2] 377156 0
Before versus 2.25 hours after consumption of drink
Secondary outcome [3] 377937 0
Plasma nitrate and nitrite concentrations (via blood sample analysis with HPLC)
composite outcome
Timepoint [3] 377937 0
Before versus 2.25 hours after consumption of drink

Eligibility
Key inclusion criteria
Between the ages of 50 - 80y
Healthy individuals
Non-smokers
Minimum age
50 Years
Maximum age
80 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Advanced/elite athletes (someone who trains more than four times per week constantly for their sport and competes at a high level)
Taking blood pressure medication
Smokers

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Numbered containers
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 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
Phase 3
Type of endpoint(s)
Efficacy
Statistical methods / analysis
A power analysis was conducted (G-Power 3.1) to calculate the sample size based on the primary measure of blood pressure. Previous literature in healthy adults has shown a mean change in BP of 10 mmHg (9 SD) between BR and control. Based on this, the required sample size was 11 per group using SD of 9, with a statistical power of 0.82 and a-level set at 0.05.

Two-way repeated-measures ANOVA will be used to assess the differences across dose (low, moderate, and high) and treatment (PL and BR). Sphericity will be tested using the Mauchly’s test to ensure the assumption of sphericity was not violated, and multivariate models will be applied if these assumptions are not met. Where significant differences are found, posthoc tests with Holm-Bonferroni correction will be undertaken to assess multiple comparisons. Outliers will be excluded based on the Tukey test. Data will be presented as mean ± standard deviation. Statistical significance is set at P<0.05.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 22138 0
New Zealand
State/province [1] 22138 0
Auckland

Funding & Sponsors
Funding source category [1] 304335 0
University
Name [1] 304335 0
Massey University, Auckland
Address [1] 304335 0
Massey University East Precinct, Dairy Flat Highway (SH17), Albany, Auckland, 0632
Country [1] 304335 0
New Zealand
Primary sponsor type
University
Name
Massey University
Address
Massey University East Precinct, Dairy Flat Highway (SH17), Albany, Auckland, 0632
Country
New Zealand
Secondary sponsor category [1] 304583 0
None
Name [1] 304583 0
Address [1] 304583 0
Country [1] 304583 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 304786 0
Massey University Human Ethics Committee: Human Ethics Southern A Committee
Ethics committee address [1] 304786 0
Massey University Human Ethics Committee, Massey University, Private Bag 11 222 | Palmerston North 4442 | New Zealand
Ethics committee country [1] 304786 0
New Zealand
Date submitted for ethics approval [1] 304786 0
28/05/2018
Approval date [1] 304786 0
31/07/2018
Ethics approval number [1] 304786 0
SOA 18/30

Summary
Brief summary
In today's society, rates of disease and age-related dysfunction (e.g. cardiovascular disease and dementia) continue to grow rapidly. This has led to an interest in the use of food-based supplements and bio­active compounds to help improve or maintain one’s health and body functions. Beetroot juice has gained recent attention due to its potential health benefits. Beetroot juice contains nitrate, which has been shown to reduce blood pressure and improve physiological responses in younger and older adults, including improved baseline cardiovascular function and exercise performance. Additionally, recent evidence has indicated that increased nitric oxide (the bio­active form of nitrate) may increase blood flow to the brain improving cognition and mood in older adults. Similarly, beetroot juice consumption has been proposed to slow the process of age-related cognitive degradation. However, variations in the dose of dietary nitrate, in the form of beetroot juice, has been shown to result in differing effects on cardiovascular response and cognition in younger and older adults. Some studies have shown that the effects of nitrate supplementation on blood pressure in younger adults occur in a dose-dependent manner, with higher doses having greater effects. This is an import factor to consider when trying to provide the optimal concentration of dietary nitrate to elicit the greatest potential benefits. However, research in this area is limited and no study has investigated the dose-response relationship of dietary nitrate-rich beetroot juice in older adults or on cognitive function.

Therefore, the aim of this study is to examine the dose-response effects of four different concentrations of dietary nitrate-rich beetroot juice on cardiovascular function, cognition, and mood in older adults (50 – 80 years).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 98198 0
Mr Luke Stanaway
Address 98198 0
School of Sport, Exercise and Nutrition | College of Health Massey University | Private Bag 102904 | North Shore Mail Centre | Auckland | 0745
Country 98198 0
New Zealand
Phone 98198 0
+642102965220
Fax 98198 0
Email 98198 0
l.stanaway@massey.ac.nz
Contact person for public queries
Name 98199 0
A/Prof Ajmol Ali
Address 98199 0
School of Sport, Exercise and Nutrition | College of Health Massey University | Private Bag 102904 | North Shore Mail Centre | Auckland | 0745
Country 98199 0
New Zealand
Phone 98199 0
+64 9 213 6414
Fax 98199 0
Email 98199 0
a.ali@massey.ac.nz
Contact person for scientific queries
Name 98200 0
A/Prof Ajmol Ali
Address 98200 0
School of Sport, Exercise and Nutrition | College of Health Massey University | Private Bag 102904 | North Shore Mail Centre | Auckland | 0745
Country 98200 0
New Zealand
Phone 98200 0
+64 9 213 6414
Fax 98200 0
Email 98200 0
a.ali@massey.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Only mean and standard deviation data will be available (via the subsequent publications)
What supporting documents are/will be available?
No other documents available
Summary results
No Results