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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 role of oral bacteria on blood nitrite concentration following a beverage high in inorganic nitrate (beetroot juice)
Scientific title
The role of nitrate reductase bacteria on plasma nitrite concentration following an acute oral inorganic nitrate dose in healthy volunteers
Secondary ID [1] 288367 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Apparently Healthy participants, looking at blood pressure 297362 0
Condition category
Condition code
Cardiovascular 297551 297551 0 0

Study type
Description of intervention(s) / exposure
Participants will consume two 70mL bottles of beetroot juice containing a total of 8.4mmol of nitrate. (BEET IT shot, James White Drinks, Ipswich, UK).

The beetroot juice will be consumed as a one off, during the testing visit, in the presence of the investigator.
Intervention code [1] 293669 0
Treatment: Other
Comparator / control treatment
No control group
Control group

Primary outcome [1] 297106 0
Plasma nitrite concentration:
Three mL of blood will be drawn from the antecubital vein by a certified technician. Samples will be snap frozen with liquid nitrogen and stored at -70 degrees Celsius. 2 blood draws will be required, one before and one 2.5 hours after treatment.

Within 30 minutes of defrosting, all NO metabolite concentrations will be measured by chemiluminescence using Ionics/Sievers nitric oxide analyser.
Timepoint [1] 297106 0
Two and a half hours after beetroot juice consumption
Primary outcome [2] 297188 0
Oral Microbiome Profiling:

A tongue swab will be collected via the use of a sterile cotton swab will be rotated over the anterior dorsal tongue surface from left to right.

Clinical specimens will undergo routine microbiological analyses using a series of aerobic and anaerobic culture media. Bacteria from single colonies will be used for MALDI-TOF analysis to profile proteins within the bacteria and allow for identification of specific types of bacteria.
Timepoint [2] 297188 0
Specimen will be collected before supplementation as we hypothesise that the already established oral microbiome of an individual will affect the conversion of the supplemented nitrate (in the form of beetroot juice) to plasma nitrite.
Secondary outcome [1] 320032 0
Brachial Artery Blood Pressure: Blood pressure readings will be taken in accordance to the World Health Organisation’s STEP wise approach for measuring blood pressure with a stethoscope and sphygmanometer by a practiced technician. The participant will be asked to be seated for 15 minutes. 3 blood pressure measurements will be taken and the participant will rest 3 minutes in between each measurement. The second and third measurements will be averaged to obtain the participants blood pressure reading.
Timepoint [1] 320032 0
Two and a half hours after beetroot juice consumption

Key inclusion criteria
Male and Female
Age: 18-70 years
Non-Smoker (or not smoked for the last 3 months)
Resting SBP between 90 and 180mmHg
Resting DBP between 60 and 110mmHg
BMI under 30kg.m2
Minimum age
18 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Informed they have a dental cavity, dental surgery or oral disease in the last 3 months
Currently taking antibiotics
Currently taking Proton Pump Inhibitor medications ie. Omeprazole
Have been diagnosed with a Cardiovascular Disease

Study design
Purpose of the study
Allocation to intervention
Non-randomised 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
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The sample size for this project has been set at 75 participants.

We do not have preliminary data or a previous model to base this study on which makes sample size requirements difficult. This study is a pilot study that will provide effect size data to help in the design of a confirmatory study.

The sample size for this study has been chosen in consideration of the practical and financial limitations associated with the project. As a research group however we feel 75 subjects will likely be the maximum number we would like to recruit to inform future research funding applications, studies and generate an interesting publication.

We hope to obtain a heterogeneous population to help establish variance and confirm future confirmation studies.

Investigations in the human microbiome usually require many more subjects than 75 although it is difficult to get an accurate estimation for this as often they are actually characterising the microbiome. For example the NIH Human Microbiome Project to define normal bacterial makeup of the human body used data from 200 members of the Human Microbiome Project Consortium from nearly 80 universities and scientific institutions to report on 5 years of research. In addition the Human Oral Microbiome Database includes 1691 taxa in 13 phyla.

It is in keeping all of these factors in mind, that we believe 75 participants is an appropriate sample size for this pilot study.

Recruitment status
Reason for early stopping/withdrawal
Lack of funding/staff/facilities
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)

Funding & Sponsors
Funding source category [1] 292717 0
Name [1] 292717 0
Victoria University
Address [1] 292717 0
Ballarat Road, Footscray, Vic, 3011
Country [1] 292717 0
Primary sponsor type
Victoria University
Ballarat Road, Footscray, Vic, 3011
Secondary sponsor category [1] 291449 0
Commercial sector/Industry
Name [1] 291449 0
Bioscreen: Specialist Medical Testing Laboratory
Address [1] 291449 0
5 Little Hyde Street, Yarraville, Vic, 3013
Country [1] 291449 0

Ethics approval
Ethics application status
Ethics committee name [1] 294207 0
Human Research Ethics, Victoria University
Ethics committee address [1] 294207 0
Ballarat Road, Footscray, Vic, 3011
Ethics committee country [1] 294207 0
Date submitted for ethics approval [1] 294207 0
Approval date [1] 294207 0
Ethics approval number [1] 294207 0

Brief summary
This study seeks to expand on previous research, which found that the consumption inorganic nitrate can significantly lower blood pressure (BP) via increasing the availability of nitric oxide (NO) within the circulation. Nitrate supplementation increases NO in a two-step process 1) Nitrate to nitrite and 2) Nitrite to NO. Step one is highly dependent on oral bacteria to facilitate the reduction of nitrate to nitrite within the saliva. However, the magnitude of this conversion appears to vary from person to person and even potentially from day to day in the same individual. This variability is not completely understood but appears to be facilitated by the amount and make-up of oral bacteria in the mouth., As a result, the primary aim of this study is to determine the relationship between the type and amount of oral bacteria and the concentration of nitrite in the plasma following a high inorganic nitrate beverage (beetroot Juice). Observing the relationship between the change in plasma nitrite concentration and the change in brachial artery blood pressure following a high inorganic nitrate beverage (beetroot Juice) is a secondary aim of the study.

Participants will complete only one testing visit. Upon arrival, baseline data collection will include blood pressure, a saliva sample (to identify particular markers on the cells and pH of the oral cavity which may influence bacteria in the mouth), tongue swab (to identify the present oral bacteria) and a blood draw (for resting plasma nitrate and nitrite levels) will be taken. Participants will then be asked to consume a beverage high in inorganic nitrate (beetroot juice). Two and a half hours following supplementation participants will undergo repeat testing measures including another blood draw and BP.

To our knowledge, no other trial has used this particular model when examining the role of oral bacteria in inorganic nitrate to nitrite conversion and therefore the current study is a pilot study to help inform us of sample size requirements in a heterogeneous population and whether particular bacterial species are more or less relevant.

For patients with cardiovascular disease, nitrate supplementation provides a potential alternative source of NO, which we know they often cannot produce the same as healthy subjects do. The results of this study may contribute to our understanding of this process that could be used as an intervention for blood pressure in the future.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 62886 0
Prof Jason Allen
Address 62886 0
Victoria University
Footscray Park Campus
Ballarat Rd, Footscray VIC 3011
Country 62886 0
Phone 62886 0
+61 3 9919 4264
Fax 62886 0
Email 62886 0
Contact person for public queries
Name 62887 0
Prof Jason Allen
Address 62887 0
Victoria University
Footscray Park Campus
Ballarat Rd, Footscray VIC 3011
Country 62887 0
Phone 62887 0
+61 3 9919 4264
Fax 62887 0
Email 62887 0
Contact person for scientific queries
Name 62888 0
Prof Jason Allen
Address 62888 0
Victoria University
Footscray Park Campus
Ballarat Rd, Footscray VIC 3011
Country 62888 0
Phone 62888 0
+61 3 9919 4264
Fax 62888 0
Email 62888 0

No information has been provided regarding IPD availability
Summary results
No Results