Effects of Dietary Nitrate and Vitamin C Co-supplementation on Blood Pressure and Endothelial Function in Overweight Individuals

NCT07242066 | Completed

• 1 other identifier: FHMS 128-0224
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

The investigators have shown in two short-term studies in healthy, young participants that the combined supplementation of inorganic nitrate with vitamin C has beneficial effects on blood pressure and blood vessel wall stiffness. However, the effects of the combined supplementation have not been tested in individuals at greater cardiovascular disease risk. The investigators would like to show whether inorganic nitrate and vitamin C will produce greater effects on blood pressure and endothelial function when compared to inorganic nitrate alone versus the placebo treatment in people at greater risk of cardiovascular disease.

Conditions

Blood Pressure

Keywords

Cardiovascular disease; endothelial function; nitrate; Vitamin C

Outcome Measures

Primary Outcomes (2)

• Blood pressure

  Resting diastolic and systolic blood pressure using portable automated monitor

  Pre, 24 hours, 48 hours and 72 hours after supplementation

• Cardiac function

  Resting cardiac function using a non-invasive methodology (Finometer)

  Pre and post 3 days of supplementation

Secondary Outcomes (6)

• Flow-mediated dilation

  Pre and post 3 days of supplementation

• Saliva nitrate concentration

  Pre and post 3 days supplementation

• Urinary nitrate concentration

  Pre and post 3 days supplementation

• Saliva nitrite concentration

  Pre and post 3 days supplementation

• Urine vitamin C concentration

  Pre and post 3 days supplementation

Study Arms (3)

Placebo

PLACEBO COMPARATOR

Placebo beetroot juice and tablet

Dietary Supplement: Nitrate-depleted beetroot juice plus placebo tablet

Beetroot juice + Vitamin C

EXPERIMENTAL

Beetroot juice and Vitamin C

Dietary Supplement: Beetroot juice plus vitamin C tablet

Beetroot juice + placebo

EXPERIMENTAL

Beetroot juice + placebo tablet

Dietary Supplement: Beetroot juice plus placebo tablet

Interventions

Beetroot juice plus vitamin C tablet DIETARY_SUPPLEMENT

Concentrated beetroot juice (70 ml in the morning before breakfast and 70 ml in the evening before dinner) plus Vitamin C tablets (500mg/tablet)

Beetroot juice + Vitamin C

Beetroot juice plus placebo tablet DIETARY_SUPPLEMENT

Concentrated beetroot juice (70ml in the morning and 70 ml in the evening) plus placebo tablets (containing 500 mg of the non-nutritive sweetener aspartame)

Beetroot juice + placebo

Nitrate-depleted beetroot juice plus placebo tablet DIETARY_SUPPLEMENT

nitrate-depleted beetroot juice (70ml in the morning and 70 ml in the evening) plus placebo tablets (containing 500 mg of the non-nutritive sweetener aspartame)

Placebo

Eligibility Criteria

• Age: 50 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Participant is willing and able to give informed consent for participation in the study.
• Participant is willing and able to comply with the requirements of the study protocol.
• Non-smoking men and women.
• Aged between 50-75 years.
• Overweight and obese (BMI: over 25.0 kg/m2).

You may not qualify if:

• Having taken part in a research study in the last 3 months involving invasive procedures or an inconvenience allowance.
• Vegetarian.
• Smoking.
• Resting systolic blood pressure greater than 160 mmHg; diastolic blood pressure greater than 100 mmHg.
• Active cancer and any diagnosis of malignant cancer in the last 5 years.
• Excessive alcohol intake (\>21 units per week).
• Allergy or intolerance to the intervention food (Beetroot juice).
• Diagnosis of chronic or acute metabolic and inflammatory conditions that may interfere with the study outcomes.
• Major surgical operations.
• Use of prescribed psychiatric drugs (antidepressants, sedatives, antipsychotics), diuretics, organic nitrates, statins and proton pump inhibitors.
• Use of prescribed hormonal therapies (oestrogens, thyroxin, and progesterone), anti-hypertensive (Calcium++ channel blockers, beta-blockers, and angiotensin-converting-enzyme (ACE) inhibitors), only if the prescription had started, or the dose had been started/changed, in the previous three months.
• Non-prescribed dietary supplements if not stopped at least for 2 weeks before starting the trial.
• Use of the mouthwash during the study was not allowed as it interferes with the conversion of oral nitrate into nitrite.

Sponsors & Collaborators

• University of Nottingham: lead

Study Sites (1)

David Greenfield Human Physiology Lab, Queens Medical Centre

Nottingham, Nottinghamshire, NG7 2UH, United Kingdom

Location

Related Publications (3)

• Deanfield JE, Halcox JP, Rabelink TJ. Endothelial function and dysfunction: testing and clinical relevance. Circulation. 2007 Mar 13;115(10):1285-95. doi: 10.1161/CIRCULATIONAHA.106.652859. No abstract available.

  PMID: 17353456 BACKGROUND

• Forstermann U. Nitric oxide and oxidative stress in vascular disease. Pflugers Arch. 2010 May;459(6):923-39. doi: 10.1007/s00424-010-0808-2. Epub 2010 Mar 21.

  PMID: 20306272 BACKGROUND

• Gori T, Munzel T. Oxidative stress and endothelial dysfunction: therapeutic implications. Ann Med. 2011 Jun;43(4):259-72. doi: 10.3109/07853890.2010.543920. Epub 2011 Feb 1.

  PMID: 21284528 BACKGROUND

MeSH Terms

Conditions

Cardiovascular Diseases

Interventions

Ascorbic Acid

Intervention Hierarchy (Ancestors)

Sugar Acids; Acids, Acyclic; Carboxylic Acids; Organic Chemicals; Hydroxy Acids; Carbohydrates

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Human Physiology

Study Record Dates

• First Submitted: December 5, 2024
• First Posted: November 21, 2025
• Study Start: November 25, 2024
• Primary Completion: August 1, 2025
• Study Completion: August 22, 2025
• Last Updated: December 2, 2025

Record last verified: 2025-11

Locations

GB (1)