Skip to main content
OpenTrials
Completed

NCT Number: NCT02553733

Effect of Beetroot Juice on Coronary Blood Flow and Walking Performance in PAD

In this study the investigators will test the hypothesis that short-term consumption of inorganic nitrate (supplied in concentrated beetroot juice) enhances coronary blood flow responses, large artery hemodynamics, and leg oxygenation/exercise tolerance in patients with peripheral arterial disease (PAD). Understanding and improving blood flow regulation in the heart and skeletal muscles of patients with PAD is important because exercise triggers symptoms of leg pain and substantially raises blood pressure and myocardial demand in these patients.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Peripheral Arterial Disease Arterial Occlusive Diseases Arteriosclerosis Atherosclerosis Cardiovascular Diseases Peripheral Vascular Diseases Vascular Diseases

Age range

21 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Milton S. Hershey Medical Center

Hershey, Pennsylvania, 17033, United States

About this study

Peripheral arterial disease (PAD) is a strong predictor of cardiovascular mortality and negatively affects functional capacity and quality of life for as many as 14 million patients in the U.S. alone. One open-label study showed that acute consumption of beetroot juice improved 6 min walk performance, reduced blood pressure, and enhanced leg muscle oxygenation in PAD patients. However, no studies have rigorously confirmed these findings in a double-blind manner, nor have the effects of this supplement been investigated (acutely or short-term) in the coronary circulation of PAD patients.

In addition to studying its effects on graded treadmill walking performance and consequent large artery vasodilation, the present study will examine the effects of short-term beetroot juice consumption (twice/day) on both coronary and leg vasodilator (graded calf flexion) and vasoconstrictor (isometric handgrip, voluntary apnea) responses in patients with PAD. Participants will randomly consume either nitrate-rich or nitrate-depleted beetroot juice with a 7 to 14 day wash-out period between. Effects of beetroot juice consumption on plasma nitrate, nitrite and methemoglobin will also be assessed.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Patients with peripheral arterial disease (PAD)
  • Capable of giving informed consent
  • Men and women age 21- 85 years
  • Diagnosed with PAD (i.e., ankle-brachial index below 0.9)
  • Fontaine stage II or less - no pain while resting
  • Satisfactory history and physical exam

Exclusion criteria

  • Children
  • Pregnant or nursing women
  • Patients taking nitroglycerine or nitrate preparations
  • Patients taking phosphodiesterase inhibitors such as sildenafil or tadalafil
  • Patients taking proton pump inhibitors
  • Ejection fraction < 40%
  • Uncontrolled hypertension
  • Uncontrolled diabetes
  • Myocardial infarction within past 6 months or unstable angina
  • Severe lung disease (i.e., on supplemental oxygen or frequently use rescue inhalers)
  • Abnormality in hemoglobin or hematocrit or methemoglobin
  • Impaired renal function
  • Impaired liver function
  • History or diagnosis of Barrett's esophagus
  • Known allergy to beetroot juice or lemon juice
  • Inability to walk on a treadmill at a moderate pace (2.0 miles/hour)

Treatment and study plan

Beetroot juice

Drug

This beverage contains 0.3 g of inorganic nitrate per 70 ml container, and is bottled and supplied by James White Drinks (UK).

Other names: Beet-It Organic Shot

Beetroot juice placebo

Drug

This beverage is identical in look and taste to the Beet-It organic shot, but has the nitrate removed. It is also bottled and supplied by James White Drinks (UK).

Other names: Beet-It organic placebo

Primary outcomes

  1. Peak Treadmill Time

    Time frame: 4 to 6 days after initiating daily ingestion of beetroot juice

    Peak treadmill time was determined using the Gardner treadmill protocol, measured as the number of seconds the participant was able to walk until they asked to stop the test due to leg fatigue.

Secondary outcomes

  1. Coronary Flow Velocity Response to Peak Plantar Flexion Exercise

    Time frame: 4 days after initiating daily ingestion of beetroot juice

    Change in LAD coronary artery flow velocity, measured using transthoracic ultrasound, from baseline rest to peak plantar flexion exercise. Single leg plantar flexion exercise of the most symptomatic leg was performed at a rate of 20 contractions per minute, with increases in workload (1 kg) every minute until volitional fatigue, or until maximum exercise duration of 14 min was reached.

  2. Resting Blood Pressure

    Time frame: 4 to 6 days after initiating daily ingestion of beetroot juice

    Resting mean arterial blood pressure (mmHg) obtained prior to the exercise treadmill test obtained using an automated arm blood pressure cuff.

Other outcomes

  1. Plasma Nitrate Concentration Prior to Plantar Flexion Test Visit.

    Time frame: 4 to 6 days after initiating ingestion of beetroot juice

    Venous blood samples were collected via venipuncture for storage and later determination of plasma nitrate concentration at Wake Forest University.

Sponsors and collaborators

Lead sponsor

David N. Proctor, PhD

Other

Collaborators

  • Milton S. Hershey Medical Center
  • Wake Forest University Health Sciences

Registry information

Official study title

Effects of Dietary Nitrate Supplementation on Coronary Blood Flow and Walking Performance in Peripheral Arterial Disease

Acronym: HeartBeet

Important dates

Study start
2015
Primary completion
2020
Study completion
2020
First posted
Sep 18, 2015
Registry last updated
Aug 13, 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.

Related clinical trials

Published trials that share one or more normalized conditions with this study.