Examination of the Distribution of Nitrate Reducing Bacteria in the Human Oral Cavity

NCT ID: NCT03068962

Last Updated: 2017-03-03

Basic Information

• Recruitment Status: UNKNOWN
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-03-31
• Study Completion Date: 2018-03-31

Brief Summary

Dietary nitrate have been shown to have health benefits including lowering blood pressure (Hobbs et al, 2012), improving endothelial function and inhibiting platelet aggregation in healthy humans (Lidder & Webb, 2013). The main sources of dietary nitrate in the human diet are vegetables such as beetroot. Nitrates are converted to nitrites then nitric oxide (NO), following their reduction by commensal oral bacteria and those residing in the gastrointestinal tract (Hord, Tang, & Bryan, 2009; Lidder & Webb, 2013). A recent study has shown following elimination of oral bacteria by the use of a chlorhexidine based antiseptic mouthwash, the conversion of nitrate to nitrite is prevented and this is accompanied by a statistically significant increase in blood pressure in normotensive subjects (Kapil et al., 2013). To date, very few studies have investigated the potential role of these oral bacteria in control of blood pressure and if there are any inter and intra-individual differences in bacterial composition.

Detailed Description

Volunteers will be provided with an outline of the study and asked to complete a medical and lifestyle questionnaire (in person, email or over the phone). Potentially suitable participants will be identified and asked to attend a screening session during which the study will be explained in more detail before a consent form is signed. Anthropometric measurements will then be taken such as weight, height and blood pressure. Subjects who meet the inclusion criteria will be invited to a further screening session during which time a dentist will check for dental diseases (e.g. current dental cavities or periodontal infection). The oral bacteria samples will be collected in the morning on site at the Department of Food and Nutritional Sciences (Hugh Sinclair Unit of Human Nutrition) on four visit days (including screening visit).On the day before each study visit the volunteers will need to have a low nitrate diet, refrain from strenuous exercise and alcohol, and drink low nitrate mineral water. They will be required to fast overnight and only drink water. In the morning, they will be asked to refrain from brushing their teeth or using mouthwash.

When they arrive in the unit in the fasted state, they will then be randomised to one of three treatments:

• Rinse mouth with low nitrate Buxton mineral water followed by holding 10 ml of beetroot juice (~6 mmol nitrate) for 5 min,
• Rinse mouth with low nitrate Buxton mineral water followed by holding 10 ml of low nitrate mineral water in the mouth for 5 min or
• Rinse with antiseptic mouthwash before holding 10 ml of beetroot juice in the mouth for 5 min.

After 5 mins of holding low nitrate water or beetroot juice in the mouth, they will then spit the whole mouth rinse into a sterile ice-chilled tube.

To evaluate the nitrate reduction in different areas of the oral cavity, the researchers will put filter paper squares which have been soaked in water or beetroot juice in different areas of their mouth (rear, mid and front tongue, tooth surface, buccal surface, hard palate, and sublingual). Volunteers will be required to keep the filter papers in their mouth for 90 seconds before they are removed.

Finally, the oral bacteria will be collected from the 7 sites by sliding a piece of sterile oral floss between the 2 back molars and by swabbing a micro brush along the buccal cervical margin of premolars and rear, mid, front tongue. Saliva will be obtained using a sterile cotton swab. All samples will be placed into sterile tubes (Eppendorfs). Mouth rinse will be collected in sterile ice-chilled Falcon tubes.

Volunteers will then be provided with a light breakfast before they leave the unit. Facilities will be available for participants to brush their teeth before they leave the clinical unit.

The study visits will be separated by at least 1 week.

Conditions

No Dental Disease; Non-smoking

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

beetroot juice

Rinse mouth with low nitrate Buxton mineral water followed by holding 10 ml of beetroot juice for 5 min,

Group Type: EXPERIMENTAL

beetroot Juice

Intervention Type: OTHER

Beetroot Juice

low mineral water (Buxton water)

Rinse mouth with low nitrate Buxton mineral water followed by holding 10 ml of low nitrate mineral water in the mouth for 5 min or

Group Type: EXPERIMENTAL

Buxton water

Intervention Type: OTHER

natural mineral water

antiseptic mouthwash then beetroot juice

Rinse with antiseptic mouthwash before holding 10 ml of beetroot juice in the mouth for 5 min

Group Type: EXPERIMENTAL

beetroot Juice

Intervention Type: OTHER

Beetroot Juice

antiseptic mouthwash then beetroot juice

Intervention Type: OTHER

Chlorhexidine glocunate

Interventions

beetroot Juice

Beetroot Juice

Intervention Type: OTHER

Buxton water

natural mineral water

Intervention Type: OTHER

antiseptic mouthwash then beetroot juice

Chlorhexidine glocunate

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Male and female
• A signed consent form
• Age 18-55 years
• Non-smoking, healthy individuals
• BMI 18.5 - 30 kg/m2

Exclusion Criteria

• Diagnosed with a chronic illness
• 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 or taken antibiotics within the last 3 months
• Current diagnosis of dental caries, gingivitis, or periodontal disease or chronic oral complaints or Existing oral pathology (active caries lesions and/or periodontal disease; mucosal lesions; poor occlusion)
• Current smoker (regular and electronic cigarettes and cigars)
• Participating in a dietary intervention study.
• Excessive alcohol consumption (> 21 units/wk male, >14 units/wk female)
• Females who are pregnant or lactating
• Reduced salivary flow (unstimulated flow less than 0.1 ml/min);
• less than four natural (enamel) buccal surfaces of upper molars available;
• presence of fixed or removable oral appliances (e.g., dentures, orthodontic wires)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 55 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Reading

OTHER

Sponsor Role: lead

Responsible Party

Julie Lovegrove

Professor of Human Nutrition

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Julie A Lovegrove, BSc, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Reading

Locations

Department of Food and Nutritional Sciences, University of Reading

Reading, Berkshire, United Kingdom

Countries

United Kingdom

Central Contacts

Julie A Lovegrove, BSc, PhD

Role: CONTACT

j.a.lovegrove@reading.ac.uk

0044118378 ext. 6418

Hayat S Alzahrani, MSc

Role: CONTACT

h.s.alzahrani@student.reading.ac.uk

07496966022

Facility Contacts

Julie A Lovegrove, BSc, PhD

Role: primary

j.a.lovegrove@reading.ac.uk

0044118 378 ext. 5361

Hayat Alzahrani, MSc

Role: backup

h.s.alzahrani@student.reading.ac.uk

References

Hobbs DA, Kaffa N, George TW, Methven L, Lovegrove JA. Blood pressure-lowering effects of beetroot juice and novel beetroot-enriched bread products in normotensive male subjects. Br J Nutr. 2012 Dec 14;108(11):2066-74. doi: 10.1017/S0007114512000190. Epub 2012 Mar 14.

Reference Type: BACKGROUND

PMID: 22414688 (View on PubMed)

Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009 Jul;90(1):1-10. doi: 10.3945/ajcn.2008.27131. Epub 2009 May 13.

Reference Type: BACKGROUND

PMID: 19439460 (View on PubMed)

Kapil V, Haydar SM, Pearl V, Lundberg JO, Weitzberg E, Ahluwalia A. Physiological role for nitrate-reducing oral bacteria in blood pressure control. Free Radic Biol Med. 2013 Feb;55:93-100. doi: 10.1016/j.freeradbiomed.2012.11.013. Epub 2012 Nov 23.

Reference Type: BACKGROUND

PMID: 23183324 (View on PubMed)

Lidder S, Webb AJ. Vascular effects of dietary nitrate (as found in green leafy vegetables and beetroot) via the nitrate-nitrite-nitric oxide pathway. Br J Clin Pharmacol. 2013 Mar;75(3):677-96. doi: 10.1111/j.1365-2125.2012.04420.x.

Reference Type: BACKGROUND

PMID: 22882425 (View on PubMed)

Other Identifiers

32/16

Identifier Type: -

Identifier Source: org_study_id