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Trial registered on ANZCTR


Registration number
ACTRN12612000643875
Ethics application status
Approved
Date submitted
15/06/2012
Date registered
18/06/2012
Date last updated
12/01/2016
Type of registration
Retrospectively registered

Titles & IDs
Public title
Acute effects of nitrate-rich spinach on arterial stiffness in healthy men and women
Scientific title
Acute effects of nitrate-rich spinach on arterial stiffness in healthy men and women
Secondary ID [1] 280685 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Blood pressure 286712 0
Vascular function 286719 0
Condition category
Condition code
Cardiovascular 287008 287008 0 0
Hypertension
Diet and Nutrition 287009 287009 0 0
Other diet and nutrition disorders
Public Health 287010 287010 0 0
Other public health

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
A randomised controlled cross-over designed study will be performed. Each participant will complete two visits to the University of Western Australia, School of Medicine and Pharmacology located at Royal Perth Hospital. The acute effects on arterial stiffness and blood pressure of two energy-matched (~2000 kJ) meals will be compared. The meals provided at each visit will contain either:
(1) 250 mg of nitrate derived from spinach (spinach);
(2) <5 mg of nitrate (control).
The two visits will be administered in random order, one week apart on the same day and at the same time of day as far as possible. Prior to each visit participants will consume a low nitrate meal for dinner (which will not contain green leafy vegatables or beetroot). Prior to the first visit, participants will document the meal so that they are able to repeat it for the second visit.
Each visit will begin in the morning between 08:00 and 10:00 with participants having fasted for at least 12 hours. Baseline measurements will be performed prior to the meal. The meal provided will consist of a white bread chicken and cheese sandwich, with or without 250 g of cooked spinach (255 kJ) containing 250 mg of nitrate. The meal will be consumed over a 15 minute period. Nitrate concentrations in vegetables may vary with season, method of cultivation and storage conditions. To account for this, the spinach will be taken from a single batch of frozen spinach from a commercial supplier, and thawed prior to use. Rice milk (100 mL) will be used as the energy matched low nitrate control for the extra energy provided by the spinach. Outcome measurements will then performed again at specific time points up to 240 minutes (4 hours) post meal.
Intervention code [1] 285093 0
Treatment: Other
Intervention code [2] 285102 0
Prevention
Comparator / control treatment
Low nitrate meal
Control group
Active

Outcomes
Primary outcome [1] 287342 0
Arterial stiffness measured as pulse wave velocity (PWV) using applanation tonometry (SphygmoCor pulse wave analysis system: AtCor Medical, Sydney, Australia. Model MM3. Software version 9)
Timepoint [1] 287342 0
Baseline and then again at 100 min and 200 min post meal
Secondary outcome [1] 297949 0
Arterial stiffness measured as augmentation index (AIx)using applanation tonometry (SphygmoCor pulse wave analysis system: AtCor Medical, Sydney, Australia. Model MM3. Software version 9)
Timepoint [1] 297949 0
Baseline and then again at 100 min and 200 min post meal
Secondary outcome [2] 297950 0
Arterial elasticity/compliance measured as the large artery elasticity index (LAEI) and the small artery elasticity index (SAEI) using pulse contour analysis of the radial artery pulse wave (HDI/Pulse wave CR-2000 instrument: Hypertension Diagnostics, Inc., Eagan, Minnesota, USA)
Timepoint [2] 297950 0
Baseline and then again at 140 min and 220 min post meal
Secondary outcome [3] 297951 0
Office blood pressure , mesured as systolic blood pressure, diastolic blood pressure and pulse pressure (Dinamap 1846SX/P oscillometric recorder: Critikon Inc., Tampa, FL, USA).
Timepoint [3] 297951 0
Baseline and then every 30 minutes to 210 minutes post meal
Secondary outcome [4] 297952 0
Salivary nitrate and nitrite concentrations (measured by gas chromatography-mass spectrometry)
Timepoint [4] 297952 0
Baseline and then again at 120 minutes post meal

Eligibility
Key inclusion criteria
Healthy men and women
Minimum age
21 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
current smoking;
BMI <18 or >35 kg/m2;
systolic blood pressure (SBP) <110 or > 130 mmHg or diastolic blood pressure (DBP) <65 or > 80 mmHg;
use of antihypertensive or cholesterol lowering medication;
history of cardiovascular or peripheral vascular disease;
diagnosed type 1 or type 2 diabetes; any major illness such as cancer; a psychiatric illness;
recent history of asthma, renal, liver or gastrointestinal disease, or gout;
use of antibiotics within previous 2 months;
current or recent (within previous 6 months) significant weight loss or gain (> 6% of body weight);
> 30g/day alcohol consumption;
woman who were pregnant, lactating or wishing to become pregnant during the study;
inability or unwillingness to consume foods provided in the trial.

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)
There are two treatments in the cross-over design study. The treatment order for eligible individuals will be randomly assigned using computer generated random numbers. The treatment order allocation will be sealed in numbered envelopes. The envelopes will be used for randomisation by opening an envelope, in consecutive order, as participants are entered into the study. The envelopes will be held by an independent person within the University of Western Australia. The study coordinator will contact the independent person to obtain the next available envelope once an individual is deemed eligible. The envelope will be opened and the code will be recorded.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer-generated random numbers using Microsoft Excel
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

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
7/11/2011
Actual
7/11/2011
Date of last participant enrolment
Anticipated
18/06/2012
Actual
18/06/2012
Date of last data collection
Anticipated
Actual
Sample size
Target
20
Accrual to date
Final
26
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 285449 0
Government body
Name [1] 285449 0
National Health and Medical Research Council
Country [1] 285449 0
Australia
Primary sponsor type
University
Name
University of Western Australia
Address
The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009
Country
Australia
Secondary sponsor category [1] 284297 0
None
Name [1] 284297 0
Address [1] 284297 0
Country [1] 284297 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 287461 0
University of Westren Australia Human Research Ethics Committee
Ethics committee address [1] 287461 0
The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009
Ethics committee country [1] 287461 0
Australia
Date submitted for ethics approval [1] 287461 0
Approval date [1] 287461 0
09/09/2011
Ethics approval number [1] 287461 0
RA/4/1/4956

Summary
Brief summary
Consumption of foods and beverages rich in nitrate can increase circulating nitrite and nitric oxide, improve endothelial function and lower blood pressure acutely. Effects of dietary nitrate on arterial stiffness have yet to be explored. We aim to assess the acute effects of a single meal containing nitrate-rich spinach on arterial stiffness in healthy men and women. Effects on blood pressure will also be assessed.
Trial website
Trial related presentations / publications
Liu AH, Bondonno CP, Croft KD, Puddey IB, Woodman RJ, Rich L, Ward NC, Vita JA, Hodgson JM. Effects of a nitrate-rich meal on arterial stiffness and blood pressure in healthy volunteers. Nitric Oxide 2013; 35:125-130
Public notes

Contacts
Principal investigator
Name 34322 0
A/Prof Jonathan Hodgson
Address 34322 0
UWA School of Medicine and Pharmacology, GPO Box X2213, Perth, WA 6847 Australia
Country 34322 0
Australia
Phone 34322 0
61 8 9224 0267
Fax 34322 0
Email 34322 0
[email protected]
Contact person for public queries
Name 17569 0
Jonathan Hodgson
Address 17569 0
UWA School of Medicine and Pharmacology, GPO Box X2213, Perth, WA 6847
Country 17569 0
Australia
Phone 17569 0
61 (0)8 9224 0267
Fax 17569 0
61 (0)8 9224 0246
Email 17569 0
[email protected]
Contact person for scientific queries
Name 8497 0
Jonathan Hodgson
Address 8497 0
UWA School of Medicine and Pharmacology, GPO Box X2213, Perth, WA 6847
Country 8497 0
Australia
Phone 8497 0
61 (0)8 9224 0267
Fax 8497 0
61 (0)8 9224 0246
Email 8497 0
[email protected]

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