Inter-individual Variation in the Blood Pressure Lowering Effects of Dietary Nitrate

December 4, 2023 updated by: Newcastle University

Effects of Dietary Nitrate on Blood Pressure: Exploring the Repeatability and Inter-individual Variation in Responses

Dietary nitrate supplementation, often in the form of beetroot juice, has been shown to lower blood pressure and could play a role in preventing or treating hypertension. However, it is currently unclear: a) how reproducible this response is within the same individual on different occasions, and b) whether there are genuine individual differences in the blood pressure lowering effects of dietary nitrate. This study will use a novel replicated cross-over design (2 x nitrate conditions, 2 x placebo conditions) to examine the reproducibility and inter-individual variability in the blood pressure lowering effects of dietary nitrate supplementation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The investigators will undertake a replicated cross-over randomised controlled trial (i.e., a study involving 2 x identical experimental conditions and 2 x identical control conditions), to explore the reproducibility of the blood pressure lowering effects of nitrate-rich beetroot juice, and to identify if there are genuine individual differences in the blood pressure-lowering effects of this supplement. Participants will be recruited via posters, email and social media, and interested individuals will be invited to attend the laboratory on 5 occasions.

Visit 1: Potential participants will be invited to attend a screening session at Newcastle University to identify if they are eligible to participate. They will have an opportunity to discuss the study with a researcher and will provide written consent. They will then complete a screening questionnaire and provide a measure of their height, weight and blood pressure. Eligible participants will be invited to attend 4 experimental trials (2 x nitrate-rich beetroot juice conditions, 2 x placebo conditions) over 2-3 weeks with a minimum of 3 days wash-out between visits. If individuals are ineligible to participate this will be explained to them and they will be thanked for their time.

Visits 2-5: On the day before the first trial, participants will be asked to record what they eat and then replicate this as closely as possible for all future visits. In the morning of each trial, participants will be asked to arrive at the laboratory between 7-9 am having fasted since 10 pm the night before. The participants will be required to rest for 10 minutes, after which a measure of their blood pressure will be obtained. Participants will then be provided with breakfast (a bowl of porridge) and 140 ml concentrated nitrate-rich (~12.5 mmol nitrate) or nitrate-depleted beetroot juice (~0 mmol nitrate). Participants will then be asked to sit in the laboratory for 2.5 hours, during which time they can read quietly or use a computer. The investigators will then obtain a further measure of their blood pressure and collect a blood sample from a vein in their arm via venepuncture, to measure markers of nitric oxide, a signalling molecule in the body which is thought to mediate the blood pressure lowering effects of nitrate-rich beetroot juice.

Study Type

Interventional

Enrollment (Actual)

15

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
    • Northumberland
      • Newcastle Upon Tyne, Northumberland, United Kingdom, NE24HH
        • Human Nutrition & Exercise Research Centre

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy male volunteers
  • Aged 18 - 45 years

Exclusion Criteria:

  • Aged less than 18 or more than 45 years old
  • Female
  • Currently taking any medication or antibiotics
  • Attending general practitioner for a health problem or on a hospital waiting list
  • Currently taking part in another research study which could conflict with the requirements for this investigation
  • Regularly use antibacterial mouthwash and unwilling to stop using this throughout the study period
  • Current smoker
  • History of kidney, liver or cardiovascular disease
  • Have diabetes
  • Have a gastrointestinal disorder
  • Recent history (past 1 year) of cancer
  • Use of other dietary supplements e.g., pre and probiotics
  • Currently dieting
  • Have a known allergy to any components within the dietary supplement

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental condition 1
Acute supplementation with 140 ml Beet It Sport Shots, James White Ltd (~400mg dietary nitrate)
Dietary supplement: Beet It Sport Shot
Acute supplementation with 140 ml Beet It Sport Shots, James White Ltd, containing ~400mg dietary nitrate
Experimental: Experimental condition 2
Acute supplementation with 140 ml Beet It Sport Shots, James White Ltd (~400mg dietary nitrate)
Dietary supplement: Beet It Sport Shot
Acute supplementation with 140 ml Beet It Sport Shots, James White Ltd, containing ~400mg dietary nitrate
Placebo Comparator: Control condition 1
Acute supplementation with 140 ml nitrate-depleted Beet It Sport Shots, James White Ltd (~0mg dietary nitrate)
Dietary supplement: Beet It Sport Shot Placebo
Acute supplementation with 140 ml Beet It Sport Shots Placebo, James White Ltd, in which the nitrate has been removed via an ion exchange resin, containing ~ 0 mg dietary nitrate
Placebo Comparator: Control condition 2
Acute supplementation with 140 ml nitrate-depleted Beet It Sport Shots, James White Ltd (~0mg dietary nitrate)
Dietary supplement: Beet It Sport Shot Placebo
Acute supplementation with 140 ml Beet It Sport Shots Placebo, James White Ltd, in which the nitrate has been removed via an ion exchange resin, containing ~ 0 mg dietary nitrate

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blood pressure of the brachial artery
Time Frame: Immediately prior to supplementation and for 2.5 hours after supplementation
Blood pressure of the brachial artery
Immediately prior to supplementation and for 2.5 hours after supplementation

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Plasma nitrite concentrations
Time Frame: 2.5 hours after supplementation
Plasma nitrite concentrations
2.5 hours after supplementation

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Newcastle University

Collaborators

University of Nottingham
Liverpool John Moores University
University of the West of Scotland
Aspire Academy

Investigators

  • Principal Investigator: Oliver Shannon, PhD, Newcastle University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 15, 2022

Primary Completion (Actual)

September 25, 2023

Study Completion (Actual)

September 25, 2023

Study Registration Dates

First Submitted

August 22, 2022

First Submitted That Met QC Criteria

August 23, 2022

First Posted (Actual)

August 24, 2022

Study Record Updates

Last Update Posted (Estimated)

December 5, 2023

Last Update Submitted That Met QC Criteria

December 4, 2023

Last Verified

December 1, 2023

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • NU013253

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data will be uploaded to a repository following publication of the study results

IPD Sharing Time Frame

Within 6 months of publication of the study findings

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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