Effects of Daily Nitrate Consumption on Oral Bacteria Composition, Blood Pressure and Vascular Function

NCT03784742 | Completed

• 1 other identifier: 347890
• Study Type: interventional
• Target: 28
• Locations: 1 country
• Sites: 1

Brief Summary

Diseases of the heart and blood vessels, including raised blood pressure, are one of the leading causes of death worldwide. Higher intakes of dietary nitrate, found abundantly in root vegetables such as beetroot, have been shown to have health benefits including lowering blood pressure and improving the elasticity of blood vessels. Bacteria which reside in the mouth and those in the gastrointestinal tract play an important role in converting dietary nitrate to nitrite and nitric oxide (a chemical which promotes the relaxation of blood vessels). In particular, removal of oral bacteria by using antiseptic mouthwash is accompanied by an increase in blood pressure in subjects with normal blood pressure, even after consuming nitrate-rich foods. To date, very little is known about the role of these oral bacteria in the control of blood pressure, and if there are any differences in bacterial composition between individuals.

Conditions

No Dental Disease; Non-smoking

Outcome Measures

Primary Outcomes (2)

• Change in blood pressure measure

  Systolic blood pressure, diastolic blood pressure and pulse pressure

  Before and after each 8 week intervention

• Change in oral bacteria composition

  Oral bacteria composition determined using next generation sequencing.

  Before and after each 8 week intervention

Secondary Outcomes (12)

• Change in vascular reactivity

  Before and after each 8 week intervention

• Change in Nox concentrations in serum, urine and saliva

  Before and after each 8 week intervention

• Change in gut bacteria composition

  Before and after each 8 week intervention

• Change in fasting lipid profile

  Before and after each 8 week intervention

• Change in C-reactive protein

  Before and after each 8 week intervention

Study Arms (2)

Nitrate-rich Beetroot juice

ACTIVE COMPARATOR

Nitrate-rich beetroot juice equivalent to 3.7 mg nitrate per kg body weight daily for 8 weeks.

Other: Nitrate rich beetroot juice

Placebo beetroot juice

PLACEBO COMPARATOR

Placebo beetroot juice (equivalent volume to the amount of nitrate-rich beetroot juice consumed) daily for 8 weeks.

Other: Placebo beetroot juice

Interventions

Nitrate rich beetroot juice OTHER

James White Drinks Limited beetroot juice (0.4-0.45 g nitrate/70 ml drink).

Nitrate-rich Beetroot juice

Placebo beetroot juice OTHER

James White Drinks Limited Placebo beetroot juice (0 nitrate/70 ml drink).

Placebo beetroot juice

Eligibility Criteria

• Age: 18 Years - 64 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Male and female;
• A signed consent form;
• Blood pressure \<140/90 mm Hg;
• BMI range 18.5 - 39.9 kg/m2;
• Age 18-64 years;
• Non-smoking;
• Not taking blood pressure lowering medication or using medications known to influence vascular function such as a glyceryl trinitrate (GTN) spray;
• No recent (within 3 months) or current use of antibiotics.

You may not qualify if:

• Diagnosed with a chronic illness;
• Anaemia defined as a haemoglobin \< 115 g/l for women and \<130 g/l for men;
• Individuals with food allergies or allergies to medicated mouthwash or ingredients in the oral products;
• Requirements to take long-term medication active on the oral cavity including prebiotics and probiotics or have taken antibiotics within the last 3 months;
• Gingivitis diagnosis, or periodontal disease or chronic oral complaints or existing oral pathology.
• Less than four natural (enamel) buccal surfaces of upper molars available;
• Presence of fixed or removable oral appliances (e.g., dentures, orthodontic wires); xerostomia (a persistent dry mouth) diagnosis;
• Current smoker;
• Already participating in a dietary intervention study or clinical trial;
• Excessive alcohol consumption (\> 14 units/wk);
• Females who are pregnant or lactating;
• Individuals not willing to give up using mouthwash or change their dental hygiene routine. Regular consumption or use of xylitol-based products such as toothpaste and chewing gum.

Sponsors & Collaborators

• University of Reading: lead
• Saudi Cultural Bureau: collaborator

Study Sites (1)

Hugh Sinclair Unit of Human Nutrition, Department of Food and Nutritional Sciences, University of Reading

Reading, Berkshire, RG6 6AP, United Kingdom

Location

Study Officials

• Julie A Lovegrove, BSc, PhD

  University of Reading

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Human Nutrition, Head of the Hugh Sinclair Unit of Human Nutrition

Study Record Dates

• First Submitted: November 1, 2018
• First Posted: December 24, 2018
• Study Start: December 1, 2018
• Primary Completion: December 1, 2020
• Study Completion: December 1, 2021
• Last Updated: April 12, 2024

Record last verified: 2024-04

Locations

GB (1)