Inorganic Nitrate and OSA

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

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.

Study Overview

• Status: Completed
• Conditions: Obstructive Sleep Apnea
• Intervention / Treatment: Dietary supplement: Pre-beetroot juice supplementation; Dietary supplement: Post-beetroot juice supplementation

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 Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • Medical Education Building

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Beetroot Juice Low; 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; Before administering beetroot juice to subjects.; Dietary supplement: Post-beetroot juice supplementation; After administering beetroot juice to subjects.
Experimental: Beetroot Juice High; 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; Before administering beetroot juice to subjects.; Dietary supplement: Post-beetroot juice supplementation; After administering beetroot juice to subjects.
Active Comparator: Beetroot Juice Placebo; 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; Before administering beetroot juice to subjects.; Dietary supplement: Post-beetroot juice supplementation; After administering beetroot juice to subjects.

What is the study measuring?

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)

Collaborators and Investigators

• Sponsor: University of Iowa
• Investigators: Principal Investigator: Darren P Casey, PhD, University of Iowa

Study record dates

Study Major Dates

• Study Start (Actual): June 12, 2019
• Primary Completion (Actual): March 6, 2020
• Study Completion (Actual): March 6, 2020

Study Registration Dates

• First Submitted: April 19, 2019
• First Submitted That Met QC Criteria: April 24, 2019
• First Posted (Actual): April 29, 2019

Study Record Updates

• Last Update Posted (Actual): April 27, 2021
• Last Update Submitted That Met QC Criteria: April 26, 2021
• Last Verified: April 1, 2021

More Information

Terms related to this study

• Keywords: blood flow; inorganic nitrate; Peripheral chemoreflex; Common carotid artery
• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Apnea; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
• Other Study ID Numbers: 201812786

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No