Evaluating the Impact of Various Dietary Nitrate Supplements on Oral Health

Evaluating the Impact of Various Dietary Nitrate Supplementation Forms on Microbiological Markers of Oral Health and Acceptability Among Adult Participants

This study aims to investigate the effects of different dietary nitrate supplements, versus placebo, on microbiological and immunological markers associated with oral health in people aged 18-65 years.

The main research questions are:

• How do different dietary nitrate supplements (beetroot crystals vs. beetroot juice) affect oral health markers, including salivary pH and oral microbiome composition?
• What is the acceptability and ease of integrating one of dietary nitrate supplements, made from beetroot but processed as freeze dried crystals or juice, into the daily diet?

To answer these questions, the study will compare results from three groups of participants, who will be randomly assigned to one of the following study arms:

Group 1: The control group will consume a placebo beetroot supplement completely free of nitrate in juice form.

Group 2: The beetroot juice group will consume a beetroot supplement standardised to contain ~ 400 mg of nitrate in juice form.

Group 3: The beetroot crystals group will consume a beetroot supplement standardised to contain ~400 mg of nitrate in freeze dried crystal form.

The study will follow a randomised, single-blind, placebo-controlled, parallel design, and the intervention will last for four weeks. Data will be collected by providing pre- and post-intervention saliva samples tongue swabs, and various questionnaires will be completed at baseline and at the end of the study. In addition, at the end of the second week of the intervention period, participants will be asked to collect a saliva sample over three consecutive days at home.

Study Overview

• Status: Recruiting
• Conditions: Oral Health; Dietary Nitrate
• Intervention / Treatment: Dietary supplement: Control (Placebo comparator); Dietary supplement: Juice (Active comparator); Dietary supplement: Crystals (Experimental)

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Shatha Alhulaefi; Phone Number: +44783361076; Email: S.Alhulaefi2@newcastle.ac.uk

Study Locations

• United Kingdom
  • Newcastle, United Kingdom, NE2 4HH
    • Recruiting
    • Newcastle University, Newcastle upon Tyne, Tyne and Wear NE2 4HH
    • Contact: Shatha Alhulaefi; Phone Number: +44783361076; Email: S.Alhulaefi2@newcastle.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy volunteers
• Aged 18 - 65 years.

Exclusion Criteria:

• Aged less than 18 or more than 65 years old.
• Current smoking
• Alcohol consumption of greater than14 units per week.
• Diagnosis of a chronic disease (e.g., cardiovascular disease, diabetes, cancer, or gastrointestinal disorders), including oral diseases.
• Use of antibiotics within the past three months or medications/nutritional supplements that may affect the oral cavity (e.g., prebiotics, probiotics, or hormone replacement therapy).
• Regular use of antibacterial mouthwash or xylitol-containing products (e.g., gum or toothpaste) or the use of proton pump inhibitors.
• Presence of braces/invisalign or dentures.
• Known allergy to any food, including beets
• Adherence to dietary restrictions (e.g., weight loss diet)
• Eating disorders that may limit participation in the study.
• Currently pregnant, breastfeeding or trying to become pregnant.
• Participation in other studies.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Control; Daily supplementation with 70 ml nitrate-depleted Beet It Sport Shots, James White Ltd (~0mg dietary nitrate)	Dietary supplement: Control (Placebo comparator); The control group will consume a placebo supplement, entirely free of nitrate, in the form of juice (70 ml) for four weeks while maintaining their habitual diet.
Active Comparator: Juice; Daily supplementation with 70 ml Beet It Sport Shots, James White Ltd (~400mg nitrate).	Dietary supplement: Juice (Active comparator); The juice group will consume a beetroot supplement enriched with ~400 mg of nitrate in juice form (70 ml) for four weeks while maintaining their habitual diet.
Experimental: Crystals; Daily supplementation with 20g Beet It Sport Crystals, James White Ltd (~400mg nitrate).	Dietary supplement: Crystals (Experimental); The crystals group will consume a beetroot supplement enriched with ~400 mg of nitrate in crystals form (20g) for four weeks while maintaining their habitual diet.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Saliva pH	Prior to and following the intervention, participants will provide an unstimulated saliva sample for pH measurement. The pH of each saliva sample will be measured using a pre-calibrated pH meter (±0.01 pH accuracy). Measurements will be performed in three independent replicates for each sample, with the three values recorded and then averaged. This average is used for the final pH value of the sample, helping to reduce the influence of random errors and improve the accuracy and reliability of the results. The device is recalibrated prior to measurements using standard calibration solutions to ensure accurate readings.	4 weeks
Oral microbiome	Prior to and following the intervention, participants will provide unstimulated saliva and tongue swab samples. DNA will be extracted from both the saliva and tongue swab samples, and 16S rRNA sequencing will be performed to identify and quantify changes in the oral microbiome.	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Salivary nitrate/ nitrite concentrations	Prior to and following the intervention, participants will provide an unstimulated saliva sample to determine saliva nitrate and nitrite levels using ozone-based chemiluminescence. Home-collected saliva samples will also be analysed for three consecutive days to ensure compliance.	4 weeks
Saliva flow rate	Participants will provide an unstimulated saliva sample prior to and following the intervention. The saliva volume collected (in mL) will be divided by the time taken (in min) to obtain the flow rate in ml/min.	4 weeks
Salivary biomarkers	Participants will provide an unstimulated saliva sample prior to and following the intervention. If sufficient sample volume is available, exploratory analysis of salivary biomarkers related to inflammation may be considered.	4 weeks
Dry mouth severity (Xerostomia)	The impact of the study interventions on dry mouth symptom severity pre- and post-intervention will be assessed using the Summated Xerostomia Inventory-Dutch Version (SXI-D) questionnaire (Thomson et al., 2011), which has been validated in clinical and epidemiological research. Participants will provide information about their oral symptoms over the previous four weeks (e.g., feeling dry mouth or difficulty eating dry foods). Participants will be asked to select one of three options, each of which is associated with a score (Never (1); Occasionally (2) and Often, (3)). The SXI-D score range is 5-15, with higher scores indicating more severe dry mouth.	4 weeks
Oral hygiene behaviours	Participants will provide information on their oral hygiene behaviours before and after the intervention using the Oral Hygiene Behaviour Index questionnaire (Buunk-Werkhoven et al., 2011). The score ranges from 0 to 16, with a high total score indicating a high level of oral hygiene practices.	4 weeks
Dietary nitrate intake assessment	Before and after the intervention, participants will provide information about their intake of nitrate containing foods through a validated digital food frequency questionnaire(McMahon et al., 2023).	4 weeks
Intervention acceptability	The acceptability of the interventions will be assessed after the study is completed through a questionnaire designed to measure acceptability dimensions according to the Theoretical Framework of Acceptability (Sekhon et al., 2017), using a 5-point Likert scale to assess different aspects such as overall acceptability, palatability, and ease of use.	4 weeks
Participant Compliance	Compliance will be assessed using a participant-completed compliance log over a 4-week period. Participants will be asked to record: The date and time of supplement intake.; How it was consumed. Additionally, any unused supplement sachets/bottles will be collected at the final visit to help estimate adherence.	4 weeks

Collaborators and Investigators

• Sponsor: Shatha Alhulaefi
• Collaborators: Northumbria University; University of the West of Scotland; Edith Cowan University
• Investigators: Principal Investigator: Oliver Shannon, PhD, Newcastle University; Principal Investigator: Anthony Watson, PhD, Newcastle University; Principal Investigator: Sheena Ramsay, PhD, Newcastle University

Study record dates

Study Major Dates

• Study Start (Actual): May 23, 2025
• Primary Completion (Estimated): December 1, 2025
• Study Completion (Estimated): April 1, 2026

Study Registration Dates

• First Submitted: April 24, 2025
• First Submitted That Met QC Criteria: April 24, 2025
• First Posted (Actual): May 4, 2025

Study Record Updates

• Last Update Posted (Actual): May 28, 2025
• Last Update Submitted That Met QC Criteria: May 27, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: oral health; Dietary nitrate; oral microbiome; salivary acidity
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Autonomic Agents; Peripheral Nervous System Agents; Neurotransmitter Agents; Membrane Transport Modulators; Adrenergic Agents; Central Nervous System Stimulants; Dopamine Uptake Inhibitors; Neurotransmitter Uptake Inhibitors; Dopamine Agents; Adrenergic Uptake Inhibitors; Sympathomimetics; Methamphetamine
• Other Study ID Numbers: 2966/53998

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No