The Effect of Dietary Nitrate on the Oral Microbiome (Microbio)

The Effect of Dietary Nitrate on the Oral Microbiota, Markers of Nitric Oxide Bioavailability and Cardiovascular Health in in Young and Older Adults

This study evaluates whether dietary manipulation of the oral microbiota modulates cardiovascular health through effects on nitric oxide bioavailability.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Health; Identify Oral Bacteria Responsible for Nitrate Reduction
• Intervention / Treatment: Dietary supplement: Nitrate-rich beetroot juice; Dietary supplement: Nitrate-depleted beetroot juice; Other: Mouthwash

Detailed Description

Nitric oxide is an important molecule for human health because it controls blood flow and blood pressure. With aging, our ability to make nitric oxide gets worse and our blood pressure tends to increase. We can help the body produce more nitric oxide by supplementing the diet with vegetables, such as beetroot juice, which contains high amounts of nitrate. This has been shown to improve blood flow and blood pressure. The bacteria inside our mouths play an important role in helping convert the ingested nitrate to nitric oxide. The reason for this study is to find out whether there are differences in oral bacteria between young and older adults, and how the oral bacterial community and blood flow and blood pressure might change when diet is supplemented with natural, nitrate-rich beetroot juice and when we use antibacterial mouthwash. This study will help us understand how the bacteria inside our mouths might be useful for keeping us healthy.

• Study Type: Interventional
• Enrollment (Actual): 101
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Devon
    • Exeter, Devon, United Kingdom
      • Diabetes & Vascular Medicine Research Centre, Clinical Research Facility

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy young (18-30 yr) and older adults (65-80 yr)
• Male and female
• Willing to undergo the experiments as detailed in the informed consent documentation
• Willing and capable of providing written, informed consent.

Exclusion Criteria:

• Individuals receiving medication for pulmonary, cardiovascular, or metabolic conditions, ulcerative colitis or renal disease
• Having an active oral disease or dentures
• Having resting BP >140/90 mmHg
• Having used antibiotics within 3 months
• Lacking willingness or capacity to give informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: QUADRUPLE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
ACTIVE_COMPARATOR: Nitrate-rich beetroot juice; 2 x 70mL concentrated juice per day for 14 days	Dietary supplement: Nitrate-rich beetroot juice; concentrated beetroot juice
PLACEBO_COMPARATOR: Nitrate-depleted beetroot juice; 2 x 70mL concentrated juice per day for 14 days	Dietary supplement: Nitrate-depleted beetroot juice; concentrated beetroot juice
OTHER: Antibacterial mouthwash; 2 x 10mL antibacterial mouthwash per day for 14 days	Other: Mouthwash; 2 x 10 mL antibacterial mouthwash per day for 14 days

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quantity of nitrate -reducing bacteria	Change in total quantity of nitrate-reducing bacteria as measured by sequencing bacterial 16S rRNA genes	14 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Nitric oxide bioavailability - plasma nitrite	Change in nitrite concentration of plasma as measured by ozone-based chemiluminescence	14 days
Nitric oxide bioavailability - salivary nitrite	Change in nitrite concentration of saliva as measured by ozone-based chemiluminescence	14 days
Nitric oxide bioavailability - plasma nitrate	Change in nitrate concentration of plasma as measured by ozone-based chemiluminescence	14 days
Nitric oxide bioavailability - salivary nitrate	Change in nitrate concentration of saliva as measured by ozone-based chemiluminescence	14 days
Blood pressure	Change in systolic and diastolic BP	14 days
Flow mediated dilation	Change in flow mediated dilation	14 days

Collaborators and Investigators

• Sponsor: University of Exeter
• Investigators: Principal Investigator: Andrew M Jones, PhD, University of Exeter

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 10, 2018
• Primary Completion (ACTUAL): May 6, 2021
• Study Completion (ACTUAL): May 6, 2021

Study Registration Dates

• First Submitted: December 19, 2017
• First Submitted That Met QC Criteria: March 14, 2018
• First Posted (ACTUAL): March 15, 2018

Study Record Updates

• Last Update Posted (ACTUAL): May 27, 2021
• Last Update Submitted That Met QC Criteria: May 26, 2021
• Last Verified: May 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: 1718/14

Drug and device information, study documents

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