Overview

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 preand 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.

Eligibility

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.