An interventional study of Nitrate rich beetroot juice and Placebo beetroot juice in No Dental Disease and Non-smoking, sponsored by University of Reading. Completed at 1 site in United Kingdom. Open to participants aged 18 Years to 64 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2024-04-12.
Sponsored by University of Reading · Not applicable, Interventional, and Treatment
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.
Interested volunteers will be provided with an outline of the study and asked to complete a medical and lifestyle questionnaire (in person, by email or over the phone). Potentially suitable participants will be identified and asked to attend a screening session after a 12 h overnight fast (not eating during this time and only drinking water) during which the study will be explained in more detail before a consent form is signed. Anthropometric measurements will then be taken including weight, height and blood pressure. A 9 ml blood sample will also be collected on site at the Department of Food and Nutritional Sciences (Hugh Sinclair Unit of Human Nutrition). Subjects who meet the initial 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) and saliva flow rate. Volunteers without periodontal disease and with normal saliva flow will then be invited to participate in the study.
Eligible subjects will then be randomised to one of two treatments: i) up to 70 ml (the amount given will be equivalent to 3.7 mg/kg body weight) beetroot juice (James White Drinks Limited, UK) or ii) a matched volume of placebo beetroot juice (control, James White Drinks Limited, UK) to be consumed daily for 8 weeks. As drinking water is a major source of dietary nitrate, subjects will be provided with a water filter to reduce the nitrate level in their tap water for drinking and cooking during the study period. There will be a wash out period of 4 weeks between the intervention juices. In total, volunteers will be involved in the study for 20 weeks (five months).
On the day before each baseline study visit (weeks 0 and 12), volunteers will be required to fast overnight after having a low nitrate evening meal and only drinking low nitrate mineral water (Buxton mineral water), which will be provided to them, during this time. They will refrain from strenuous exercise and alcohol. On the morning of the study visit, the volunteers will be asked not to brush their teeth before they come to the clinical unit for their study visit.
When they arrive in the fasted state, the participants will be asked to provide a spot urine sample and a stool sample. Body weight and composition will be measured using the Tanita weighing scale, saliva sample and an oral bacteria sample will be collected by swabbing the tongue with a cotton swab. Volunteers will be asked to lie down for 20 minutes prior to the measurement of blood pressure and pulse wave analysis (PWA) using the Mobil-O-Graph device followed by the assessment of microvascular reactivity using Laser Doppler Imaging with iontophoresis. A blood sample of 20 ml (equivalent to just over 1 tablespoon) will then be taken before a light breakfast is provided. Volunteers will then be given a toothbrush and toothpaste to brush their teeth and asked to complete an online food frequency questionnaire (EatwellUK).
During the four-week wash-out period between interventions, participants will be instructed to avoid any beetroot juice drinks and maintain their usual dietary and lifestyle habits.
110 studies on the registry are indexed under Stomatognathic Diseases; 26 are open to participants now.
This study's enrollment of 28 is below the median of 59 across 86 interventional studies indexed under Stomatognathic Diseases.
Browse Stomatognathic Diseases studies →University of Reading is the lead sponsor of 146 studies on the registry; 20 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Male and female;
Exclusion criteria are:
Diagnosed with a chronic illness;
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 (equivalent volume to the amount of nitrate-rich beetroot juice consumed) daily for 8 weeks.
Other: Placebo beetroot juice
James White Drinks Limited beetroot juice (0.4-0.45 g nitrate/70 ml drink).
James White Drinks Limited Placebo beetroot juice (0 nitrate/70 ml drink).
Change in blood pressure measure
Systolic blood pressure, diastolic blood pressure and pulse pressure
Time frame: Before and after each 8 week intervention
Change in oral bacteria composition
Oral bacteria composition determined using next generation sequencing.
Time frame: Before and after each 8 week intervention
Change in vascular reactivity
Laser Doppler Imaging with iontophoresis.
Time frame: Before and after each 8 week intervention
Change in Nox concentrations in serum, urine and saliva
Nitrate and nitrite concentrations will be determined using high performance liquid chromatography in plasma, urine and saliva. Nitric oxide will be calculated as the sum of nitrate and nitrite concentrations. Creatinine will be measured in the urine samples to normalise the nitrate and nitrite concentrations in urine for hydration status.
Time frame: Before and after each 8 week intervention
Change in gut bacteria composition
Stool sample will be analysed to determine composition using next generation sequencing will be used to find the differences between treatments.
Time frame: Before and after each 8 week intervention
Change in fasting lipid profile
Total cholesterol, HDL-C, and triacylglycerol will be measured using a clinical chemistry analyser. LDL-C will be calculated using the Friedewald formula.
Time frame: Before and after each 8 week intervention
Change in C-reactive protein
C-reactive protein will be measured using a clinical chemistry analyser
Time frame: Before and after each 8 week intervention
Change in endothelial function
Pulse wave analysis will be measured using Mobil-O-Graph
Time frame: Before and after each 8 week intervention
Change in body weight
Body weight will be measured using a Tanita scale
Time frame: Before and after each 8 week intervention
Height measurement
Height will be measured using a stadiometer
Time frame: Before the intervention
Change in body mass index
Body mass index will be calculated from the body weight and height measurement
Time frame: Before and after each 8 week intervention
Change in insulin
Insulin levels will be measured by ELISA
Time frame: Before and after each 8 week intervention
Change in glucose
Glucose levels will be measured using a clinical chemistry analyser
Time frame: Before and after each 8 week intervention
Change in insulin sensitivity
Glucose and insulin measurements will be used to calculate the homeostatic model assessment of insulin resistance (HOMA-IR)
Time frame: Before and after each 8 week intervention
This study is completed, as verified in Apr 2024. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Reading