Inorganic Nitrate and OSA

Not Applicable

Completed

• Conditions: Obstructive Sleep Apnea
• Interventions: Dietary Supplement: Pre-beetroot juice supplementation; Dietary Supplement: Post-beetroot juice supplementation

• Registration Number: NCT03930563
• Lead Sponsor: University of Iowa

Brief Summary

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

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.

Study Timeline

• Study First Submitted: 2019-04-19
• Study First Submitted QC: 2019-04-24
• Study First Posted: 2019-04-29
• Study Start: 2019-06-12
• Primary Completion: 2020-03-06
• Study Completion: 2020-03-06
• Status Verified: 2021-04
• Last Update Submitted: 2021-04-26
• Last Update Posted: 2021-04-27

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 21

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Beetroot Juice Placebo	Post-beetroot juice supplementation	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.
Beetroot Juice Low	Pre-beetroot juice supplementation	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.
Beetroot Juice High	Post-beetroot juice supplementation	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.
Beetroot Juice Low	Post-beetroot juice supplementation	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.
Beetroot Juice Placebo	Pre-beetroot juice supplementation	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.
Beetroot Juice High	Pre-beetroot juice supplementation	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.

Primary Outcome Measures

Name	Time	Method
Changes in peripheral chemoreflex sensitivity	Before and after consuming all supplements (within three hours)	The ventilatory response to acute hypoxia will be measured via pneumotachometer.

Secondary Outcome Measures

Name	Time	Method
Changes in common carotid artery blood flow	Before and after consuming all supplements (within three hours)	Blood flow through the common carotid artery before and during hypoxia measured via Doppler ultrasound

Trial Locations

Locations (1)

Medical Education Building; 🇺🇸 Iowa City, Iowa, United States