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Trial registered on ANZCTR


Registration number
ACTRN12616001028493
Ethics application status
Approved
Date submitted
27/07/2016
Date registered
3/08/2016
Date last updated
7/07/2017
Type of registration
Prospectively registered

Titles & IDs
Public title
Impact of beet juice on leg blood flow capacity at rest and during passive movement in older adults
Scientific title
Impact of beet juice on leg blood flow capacity at rest and during passive movement in older adults
Secondary ID [1] 289770 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Nitric oxide bioavailability 299645 0
aging 299646 0
Condition category
Condition code
Cardiovascular 299595 299595 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study will use a placebo controlled, cross-over design to determine if beet juice can increase leg blood flow and femoral artery dilation for older adults.
The study will be conducted in the Exercise Science Research Laboratory at the University of the Sunshine Coast. After expressing interest in participating, all potential participants will attend an initial visit (visit 1, 60 min) to screen them against inclusion/exclusion criteria, clarify experiment details, ensure written informed consent, and to familiarise participants with the study procedures. During this visit, participants will have the opportunity to practice and become familiar with passive leg movement, ensuring appropriate muscle relaxation. Participants will then attend two experimental visits (visits 2 and 3) which will be approximately 6 hours each, separated by at least 3, but no more than 14 days. During these visits, participants will have blood pressure measured and then a blood sample will be taken for measurement of circulating nitrate (NO3-) and nitrite (NO2-). Baseline arterial stiffness, femoral artery dilation capacity (flow mediated dilatation), femoral artery blood flow (reactive hyperaemia), and blood flow during passive leg movement will be measured before the participant consumes 140 ml of concentrated beet juice or the placebo (nitrate-depleted beet juice). The beet juice and placebo taste, smell, and look the same and will be given in random order. Participants will then have a waiting period of 2 hours, which is the duration required for NO3- supplementation to significantly elevate plasma NO2- (ie the window of peak physiological effect). During this waiting period, participants will be asked to complete a medical history questionnaire (which includes smoking history and medication use) and a habitual physical activity questionnaire, Participants will be given a standardised low-nitrate meal and water and they will be free to talk, read, watch television, or undertake a sedentary activity of their choice. After the 2-hour waiting period, all baseline measurements will be repeated: blood pressure and a blood sample for NO3-/NO2- measurement, and then arterial stiffness, flow mediated dilatation, reactive hyperaemia and blood flow during passive leg movement.
Intervention code [1] 295426 0
Treatment: Other
Comparator / control treatment
The placebo is beet juice with the nitrate removed
Control group
Placebo

Outcomes
Primary outcome [1] 299066 0
Leg blood flow during reactive hyperaemia and during passive leg movement, assessed by Duplex ultrasound, will be compared following consumption of beet juice or a placebo.
Timepoint [1] 299066 0
Leg blood flow will be assessed during a reactive hyperaemia test that will be carried out immediately prior to and 3 hours after consumption and passive leg movement carried out immediately prior to and 3.5 hours after consumption,
Primary outcome [2] 299067 0
Flow mediated dilatation in the superficial femoral artery, assessed by ultrasound, will be compared following consumption of beet juice or a placebo.
Timepoint [2] 299067 0
Flow mediated dilatation will be measured immediately prior to and 3 hours after consumption of beet juice or the placebo.
Secondary outcome [1] 326056 0
Arterial stiffness, assessed using a SphygmoCor system for pulse wave analysis and pulse wave velocity, will be compared following consumption of beet juice or the placebo
Timepoint [1] 326056 0
Arterial stiffness will be assessed 1 hour prior to and 2.5 hours after consumption of beet juice or the placebo
Secondary outcome [2] 326169 0
Systolic and diastolic blood pressure, measured by sphygmomenometry, will be compared before and after consumption of beet juice or the placebo
Timepoint [2] 326169 0
Systolic and diastolic blood pressure will be measured 3 times in each arm at baseline (2 hours prior to) and 2 hours after consumption of beet juice and placebo
Secondary outcome [3] 326170 0
Blood plasma concentrations of nitrate (NO3-), assessed by chemoluminescence, will be compared following consumption of beet juice or the placebo
Timepoint [3] 326170 0
Blood plasma concentrations of nitrate will be measured at baseline (1 hour 45 minutes prior to) and 2 hours 15 minutes after consumption of beet juice and the placebo
Secondary outcome [4] 326340 0
Blood plasma concentrations of nitrite (NO2-), assessed by chemoluminescence, will be compared following consumption of beet juice or the placebo
Timepoint [4] 326340 0
Blood plasma concentrations of nitrite will be measured at baseline (1 hour 45 minutes prior to) and 2 hours 15 minutes after consumption of beet juice and the placebo

Eligibility
Key inclusion criteria
Healthy males
Live within 100km of the study venue
Minimum age
60 Years
Maximum age
75 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
unable to communicate in English
have a known communicable disease
have a known cardiovascular disease
taking medication for the reduction of blood pressure

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)
Methods used to generate the sequence in which subjects will be randomised (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 analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Blood pressure, circulating NO3- and NO2-, as well as arterial stiffness, FMD and blood flow responses to the reactive hyperaemia test and to passive leg extension will be compared before and after the beetroot juice and placebo consumption and a comparison will be made between trials using repeated measures analysis of variance (ANOVA). Post hoc testing will be used to identify the location of significant differences between trials. Statistical significance will be set at p < 0.05. Relationships between reactive hyperaemia and passive leg extension hyperaemia will be assessed using Pearson’s correlation.

The main outcome measure is leg blood flow during reactive hyperaemia and passive leg movement with and without nitrate supplementation. This has not been measured previously, however FMD, which we will also measure and is closely related to leg blood flow during the reactive hyperaemia test, has been reported in previous studies. Therefore, sample size for this experiment is based on a study with older adults (63 +/- 5 years) that reported a difference in FMD of the brachial artery following ingestion of sodium nitrate (NaNO3) (Rammos et al., 2014). In this study, average FMD increased from 6.0% +/- 0.8% to 6.5 +/- 0.8%, which was significant at P = 0.004 in this experiment with 11 participants. Setting power at 0.80 and using an alpha level of 0.05 and assuming this difference and variation, significance could be established with 10 participants (Sergeant, 2015). To allow for the possibility of a smaller effect size in leg blood flow, to compensate for the potentially high variability in change scores, and to improve the likelihood of finding significance in other measures of interest, we have selected a sample size of 15 participants in each group.


Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
16/08/2016
Actual
16/09/2016
Date of last participant enrolment
Anticipated
18/10/2016
Actual
16/11/2016
Date of last data collection
Anticipated
25/10/2016
Actual
2/12/2016
Sample size
Target
15
Accrual to date
Final
15
Recruitment in Australia
Recruitment state(s)
QLD

Funding & Sponsors
Funding source category [1] 294151 0
University
Name [1] 294151 0
University of the Sunshine Coast
Country [1] 294151 0
Australia
Primary sponsor type
University
Name
University of the Sunshine Coast
Address
Locked Bag 4
Maroochydore DC
Queensland
4558
Country
Australia
Secondary sponsor category [1] 292982 0
None
Name [1] 292982 0
Address [1] 292982 0
Country [1] 292982 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 295561 0
Univeristy of the Sunshine Coast Human Research Ethics Committee
Ethics committee address [1] 295561 0
Locked Bag 4
University of the Sunshine Coast
Maroochydore DC
Queensland 4558
Ethics committee country [1] 295561 0
Australia
Date submitted for ethics approval [1] 295561 0
04/05/2016
Approval date [1] 295561 0
16/06/2016
Ethics approval number [1] 295561 0
S/16/912

Summary
Brief summary
The aim of the project is to examine the effect of nitrate-rich beet juice on leg blood flow during reactive hyperaemia and passive leg movement. During reactive hyperaemia and passive leg movement, blood flow is known to be highly dependent on the availability of the nitrate derivative, nitric oxide. The results of this study will determine if beet juice can enhance leg blood flow and thereby provide an effective adjunct to therapeutic exercise.
The proposed study will use a placebo controlled, cross-over design to determine if beet juice can increase leg blood flow and femoral artery dilation for older adults. Specifically, we will examine leg blood flow and femoral artery diameter during reactive hyperaemia and passive hyperaemia, two tests which are known to be highly dependent on NO availability, thereby demonstrating the mechanism.

Participants will attend the laboratory on three occasions: visit 1 will include participant screening, consent, and familiarisation; visits 2 and 3 will involve nitrate-rich beet juice and placebo trials (in random order). During each of the experimental visits, before and after ingestion of the beet juice or placebo, the following will be measured: blood pressure, blood plasma NO3-/NO2-, arterial stiffness, femoral artery dilation capacity, femoral artery blood flow capacity, and blood flow during passive leg movement.

The results of this study will determine whether or not nitrate supplementation increases leg blood flow and vessel dilation during a reactive hyperaemia test and during passive leg movement. Ultimately, this experiment will demonstrate whether leg blood flow increases in response to improved NO availability for older adults. These findings will help to guide treatment for individuals with chronic diseases that limit exercise capacity, such as peripheral arterial disease, pulmonary disorders and heart failure. This study will also clarify the mechanism by which a simple dietary intervention may enhance leg blood flow, providing an effective adjunct to therapeutic exercise.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 67770 0
Mrs Meegan Walker
Address 67770 0
School of Health and Sport Sciences
Locked Bag 4
University of the Sunshine Coast
Maroochydore DC
Queensland 4558
Country 67770 0
Australia
Phone 67770 0
+61 (7) 5456-3751
Fax 67770 0
Email 67770 0
[email protected]
Contact person for public queries
Name 67771 0
Mrs Meegan Walker
Address 67771 0
School of Health and Sport Sciences
Locked Bag 4
University of the Sunshine Coast
Maroochydore DC
Queensland 4558
Country 67771 0
Australia
Phone 67771 0
+61 (7) 5456-3751
Fax 67771 0
Email 67771 0
[email protected]
Contact person for scientific queries
Name 67772 0
Mrs Meegan Walker
Address 67772 0
School of Health and Sport Sciences
Locked Bag 4
University of the Sunshine Coast
Maroochydore DC
Queensland 4558
Country 67772 0
Australia
Phone 67772 0
+61 (7) 5456-3751
Fax 67772 0
Email 67772 0
[email protected]

No information has been provided regarding IPD availability


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.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseAcute dietary nitrate supplementation improves flow mediated dilatation of the superficial femoral artery in healthy older males.2019https://dx.doi.org/10.3390/nu11050954
N.B. These documents automatically identified may not have been verified by the study sponsor.