Effect of Beet Juice Supplementation on Vascular and Inspiratory Muscle Function

Study Overview
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Brief Summary
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Older adults with coronary artery disease (CAD) have impaired vascular and inspiratory muscle function. The objective of this study is to examine the effect of beet juice supplementation on vascular and inspiratory muscle function in older adults with CAD.

Official Title
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Effect of Beet Juice Supplementation on Vascular and Inspiratory Muscle Function

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Dietary Supplement: Nitrate rich beetroot juice
* Dietary Supplement: Nitrate depleted beetroot juice


Participation Criteria
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Eligibility Criteria
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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 Men and women (women must be postmenopausal either natural or surgical) Able to give consent Exclusion Criteria: Ejection fraction <50%, unstable angina, recent myocardial infarction 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 on-going or recurrent illness Individuals that 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) Regular aerobic exercise training 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

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Nitrate rich beetroot juice<br> | Dietary Supplement: Nitrate rich beetroot juice<br>* 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.<br>|
| Placebo Comparator: Nitrate depleted beetroot juice<br> | Dietary Supplement: Nitrate depleted beetroot juice<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in endothelial function | 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. | Baseline up to following 2 weeks of experimental condition | 
| Change in inspiratory muscle function | Inspiratory muscle function including strength, power and endurance will be assessed using the POWERbreathe KH2 device | Baseline up to following 2 weeks of experimental condition | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in microvascular function | 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. | Baseline up to following 2 weeks of experimental condition | 
| Change in central arterial stiffness | The SphygmoCor XCEL device will be used to measure carotid to femoral pulse wave velocity. | Baseline up to following 2 weeks of experimental condition | 
| Change in central arterial hemodynamics | The SphygmoCor XCEL device will be used to obtain central pulse wave analysis. | Baseline up to following 2 weeks of experimental condition | 
| Change in functional capacity | Using the Duke Activity Status Index we will assess participants' ability to perform daily activities. | Baseline up to following 2 weeks of experimental condition |