Inorganic Nitrate and OSA

Study Overview
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Brief Summary
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The main purpose of this study is to determine if acute beetroot juice supplementation reduces peripheral chemoreflex sensitivity in patients with obstructive sleep apnea. All subjects will consume low-dose (BRL), higher-dose (BRH), and placebo (BRP) beetroot juice randomly on three independent study visits. Beetroot juice also improves blood flow thus, the investigators will also measure blood flow to the carotid chemoreceptors.

Detailed Description
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Four-weeks of daily beetroot juice supplementation reduces peripheral chemoreflex sensitivity in healthy older adults who have 'normal' responses to acute hypoxia. Patients with obstructive sleep apnea have exaggerated peripheral chemoreflex sensitivity. It remains unknown if beetroot juice supplementation reduces peripheral chemoreflex sensitivity in patients with obstructive sleep apnea. Additionally, increasing blood flow to the peripheral chemoreceptors reduces sensitivity. Given that beetroot juice improves blood flow, the investigators will also measure common carotid artery blood flow at rest and during hypoxia.

Official Title
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Acute Beetroot Juice Supplementation and Peripheral Chemoreflex Sensitivity in Patients With Obstructive Sleep Apnea

Conditions
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Obstructive Sleep Apnea

Intervention / Treatment
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* Dietary Supplement: Pre-beetroot juice supplementation
* Dietary Supplement: Post-beetroot juice supplementation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: OSA group: patients recently diagnosed with mild-to-moderate OSA Control group: healthy individuals Exclusion Criteria: Diagnosis of heart disease Diagnosis of diabetes Diagnosis of any autonomic disorders Diagnosis of kidney disease Diagnosis of central sleep apnea Regular physical activity exceeding 30 minutes 3 days/week A body mass index ≥40 kg/m2 Current or former use of a continuous positive airway pressure machine Current tobacco use Currently prescribed hormone replacement therapy

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Beetroot Juice Low<br>Subjects will consume beetroot juice containing 250mg inorganic nitrate and 20mg nitrite dissolved in 120ml bottled water. Peripheral chemoreflex sensitivity as well as common carotid artery blood flow will be assessed before and after supplementation. | Dietary Supplement: Pre-beetroot juice supplementation<br>* Before administering beetroot juice to subjects.<br>Dietary Supplement: Post-beetroot juice supplementation<br>* After administering beetroot juice to subjects.<br>|
| Experimental: Beetroot Juice High<br>Subjects will consume beetroot juice containing 500mg inorganic nitrate and 40mg nitrite dissolved in 120ml bottled water. Peripheral chemoreflex sensitivity as well as common carotid artery blood flow will be assessed before and after supplementation. | Dietary Supplement: Pre-beetroot juice supplementation<br>* Before administering beetroot juice to subjects.<br>Dietary Supplement: Post-beetroot juice supplementation<br>* After administering beetroot juice to subjects.<br>|
| Active Comparator: Beetroot Juice Placebo<br>Subjects will consume beetroot juice devoid of inorganic nitrate and nitrite dissolved in 120ml bottled water. Peripheral chemoreflex sensitivity as well as common carotid artery blood flow will be assessed before and after supplementation. | Dietary Supplement: Pre-beetroot juice supplementation<br>* Before administering beetroot juice to subjects.<br>Dietary Supplement: Post-beetroot juice supplementation<br>* After administering beetroot juice to subjects.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in peripheral chemoreflex sensitivity | The ventilatory response to acute hypoxia will be measured via pneumotachometer. | Before and after consuming all supplements (within three hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in common carotid artery blood flow | Blood flow through the common carotid artery before and during hypoxia measured via Doppler ultrasound | Before and after consuming all supplements (within three hours) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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inorganic nitrate, blood flow, Peripheral chemoreflex, Common carotid artery