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

David N. Proctor, PhD

Status and phase: Active, not recruiting; Phase 2

Conditions: Peripheral Arterial Disease

Treatments: Drug: Beetroot juice placebo; Drug: Beetroot juice

Study type: Interventional

Funder types: Other

Identifiers

NCT02553733

00003242

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 12 estimated patients

Sex: All

Ages: 21 to 85 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

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

Exclusion criteria

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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12 participants in 2 patient groups, including a placebo group

Beetroot juice (Beet-It Organic Shot)

Active Comparator group

Description:

Subjects will consume 70 ml of beetroot juice (Beet-It Organic Shot) twice per day (morning, afternoon) for 5 to 7 days to assess the short term effects of this nitrate supplement on graded treadmill walking responses (day 4) and vasodilator/vasoconstrictor responses in the coronary and lower leg circulations (day 5 or 6 or 7). On both study visits, subjects will consume their morning dose 1 hour 45 min before experiments begin.

Treatment:

Drug: Beetroot juice

Beetroot juice placebo (Beet-It Organic Placebo)

Placebo Comparator group

Description:

Subjects will consume 70 ml of beetroot juice placebo (Beet-It Organic Placebo) twice per day (morning, afternoon) for 5 to 7 days to assess the short term effects of this nitrate supplement on graded treadmill walking responses (day 4) and vasodilator/vasoconstrictor responses in the coronary and lower leg circulations (day 5 or 6 or 7). On both study visits, subjects will consume their morning dose 1 hour 45 min before experiments begin.

Treatment:

Drug: Beetroot juice placebo