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Completed

NCT Number: NCT04920799

Effect of Beet Juice Supplementation on Vascular and Inspiratory Muscle Function

Older adults with coronary artery disease (CAD) have impaired vascular and inspiratory muscle function. The overarching goal of this double-blind, randomized, crossover, placebo-controlled pilot trial was to inform the development of a fully powered trial to evaluate the effects of dietary nitrate supplementation in older adults with CAD. We aimed to address the following objectives: (a) assess the feasibility, tolerability, and safety of the study protocol; (b) gather preliminary evidence on the effects of nitrate-rich beetroot juice compared with nitrate-depleted beetroot juice (placebo), and estimate the effect sizes; and (c) determine if a full-scale definitive trial is justified.

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Key information

Conditions

Coronary Artery Disease Arterial Occlusive Diseases Arteriosclerosis Cardiovascular Diseases Coronary Disease Heart Diseases Myocardial Ischemia Vascular Diseases

Age range

60 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Integrative Cardiovascular Physiology Laboratory, University of Florida

Gainesville, Florida, 32611, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults with coronary artery disease (CAD) based on an angiogram >50% stenosis in any major epicardial vessel or history of myocardial infarction or history of coronary revascularization.
  • Considered to have stable CAD on optimal medical therapy
  • 60 to 85 years of age
  • Males and females (females must be postmenopausal either natural or surgical)
  • Able to give consent

Exclusion criteria

  • Unstable angina, recent myocardial infarction or heart failure within 6 months
  • Coronary revascularization, including percutaneous coronary intervention and coronary artery bypass graft or thoracic surgery within 6 months.
  • Stroke, obstructive pulmonary disease, hepatitis B, C, HIV, seizures, or other relevant ongoing or recurrent illness
  • Individuals who have participated in respiratory training within the last 12 months or cardiac rehabilitation within the last 6 months
  • Uncontrolled hypertension
  • Use of tobacco products including smoking traditional or e-cigarettes
  • Use of hormone replacement therapy in women or men (e.g., estrogen, progesterone or testosterone)
  • Unwilling to stop using mouthwash at least 1 week before the start of the study and during study participation
  • Unwilling to remain weight stable during study participation

Treatment and study plan

Nitrate Rich Beetroot Juice

Dietary Supplement

Participants will drink nitrate rich beetroot juice (2.4 floz ; Beet It Sport Nitrate 400 concentrated beetroot shot; James White Drink, ltd) twice daily for two weeks.

Nitrate depleted beetroot juice

Dietary Supplement

Participants will drink nitrate depleted beetroot juice (2.4 floz ; Beet It placebo concentrated beetroot shot; James White Drink, ltd) twice daily for two weeks.

Primary outcomes

  1. Change in endothelial function

    Time frame: Baseline up to following 2 weeks of experimental condition

    Endothelial function will be determined using brachial artery flow-mediated dilation via high resolution duplex ultrasonography. Reactive hyperemia will be produced by inflating a forearm cuff to ~250 mmHg for 5 minutes followed by rapid deflation.

  2. Change in inspiratory muscle function

    Time frame: Baseline up to following 2 weeks of experimental condition

    Inspiratory muscle function including strength, power and endurance will be assessed using the POWERbreathe KH2 device

Secondary outcomes

  1. Change in microvascular function

    Time frame: Baseline up to following 2 weeks of experimental condition

    Microvascular function will be assessed using the forearm blood flow response to submaximal handgrip exercise. Brachial artery blood flow and diameter will be assessed using ultrasound.

  2. Change in central arterial stiffness

    Time frame: Baseline up to following 2 weeks of experimental condition

    The SphygmoCor XCEL device will be used to measure carotid to femoral pulse wave velocity.

  3. Change in central arterial hemodynamics

    Time frame: Baseline up to following 2 weeks of experimental condition

    The SphygmoCor XCEL device will be used to obtain central pulse wave analysis.

  4. Change in functional capacity

    Time frame: Baseline up to following 2 weeks of experimental condition

    Using the Duke Activity Status Index we will assess participants' ability to perform daily activities.

Sponsors and collaborators

Lead sponsor

University of Florida

Other

Registry information

Important dates

Study start
2021
Primary completion
2025
Study completion
2025
First posted
Jun 10, 2021
Registry last updated
May 14, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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