Currently, there is a lack of evidence-based prevention strategies for respiratory infection and management of these conditions can be costly to the public. Airway nitric oxide provides a first line of defense against pathogens, and beetroot juice, a source of dietary nitrate, has been shown to elevate nitric oxide. The main objective of this project is to demonstrate that one week of supplementation with beetroot juice elevates airway nitric oxide during stressful periods in young adults and thereby can protect against respiratory viral infections.
Study Title Beetroot Juice Supplement for Boosting Mucosal Immunity: The NO Cold Study Objectives Aim 1: Demonstrate that a 7-day trial of daily beetroot juice or nitrate depleted placebo beetroot juice is feasible with acceptable retention and adherence during a period of real-life stress, using adherence monitoring of beetroot juice intake by cell phone recorded video; acceptable burdensomeness for participants and success of team coordination and study logistics should also be demonstrated. Aim 2: Generate initial estimates of effect size for a) elevations in exhaled nitric oxide (FENO) and b) the correlation between changes in FENO and both infection reduction and cold symptom reduction (biological signature). Aim 3: a) Examine if 2 daily doses of beetroot juice are more potent than 1 daily dose in elevating FENO, and b) investigate whether each beetroot juice dosage (1 dose and 2 doses) increases FENO more than the placebo. Exploratory aims: Explore sex as a moderator of all the Aims. Also explore effects of competitors/inhibitors of NO (arginase, asymmetric dimethylarginine) in a) reducing FENO under stress, and b) whether beetroot juice buffers any of these potential adverse effects on FENO; c) investigate whether effects of stress cortisol, which negatively impact NO, cold symptoms, and respiratory infections, are also buffered by beetroot juice. Design and Outcomes This is a double-blind, placebo controlled clinical trial to test the efficacy of beetroot juice as elevating airway NO, which is associated with reduced cold symptoms and respiratory viral infection rates, in undergraduate students aged 18-30. Interventions and Duration Participants will be receiving 1 active daily dose of beetroot juice and 1 dose of nitrate-depleted placebo beetroot juice, 2 active daily doses of beetroot juice, or 2 daily doses of nitrate-depleted placebo beetroot. Cold symptoms will be explored by questionnaire at baseline (in a low stress period during the semester) and subsequently twice during the final exam period, once at an early stage of the finals (days 1-3 of the final exam period), and once at a later stage (days 4-6). A follow-up online questionnaire packet will be administered 3 days after the last final day. FENO, sampling for viral PCR, salivary cortisol, and exhaled breath condensate will be undertaken at baseline, early finals, and late finals (in-person assessments are not feasible at follow-up, because students leave campus after finals). Sample Size and Population The sample size is 150 students (n=66 at SMU site, n=84 at Baylor site). Female and male students 18-30 years old will be recruited from Baylor and SMU. The investigators will make an extra effort to guarantee equal representation of both genders. Participants can be from any ethnic or cultural background, as long as they can understand and read English adequately. The student population of both universities combined is diverse (28.5-38.5% minorities). The investigators will stratify by sex and by site, to randomize participants to receiving 1 active daily dose of beetroot juice and 1 dose of nitrate-depleted placebo beetroot juice, 2 active daily doses of beetroot juice, or 2 daily doses of nitrate-depleted placebo beetroot juice (n=50 per group).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
150
Participants will take on dose in the morning and one in the afternoon, for 7 days during their final academic examinations
Southern Methodist University
Dallas, Texas, United States
RECRUITINGBaylor University
Waco, Texas, United States
RECRUITINGExhaled Nitric Oxide
The Fraction of NO in Exhaled Breath (FENO, in ppb) will be measured with an electrochemical gas analyzer (NIOX vero).
Time frame: Baseline (non-stress mid point of semester), 1-3 days into active beetroot shots (during final examination period), 4-6 days into active beetroot shots (during final examination period)
Viral Polymerase Chain Reaction
Binary positive/negative test results for a panel of viral and bacterial respiratory pathogens.
Time frame: Baseline (non-stress mid point of semester), 4-6 days into active beetroot shots (during final examination period)
Wisconsin Upper Respiratory Symptom Survey (WURSS)
Assess symptoms of acute upper respiratory tract infections (common cold symptoms) by questionnaire
Time frame: Baseline (non-stress mid point of semester), 1-3 days into active beetroot shots (during final examination period), 4-6 days into active beetroot shots (during final examination period), 1-3 days after finishing beetroot shots (after final examinations)
Adherence monitoring (feasibility)
Participants will upload a cell phone video of their intake for that day to a secure cloud folder, time stamp in comparison to assigned intake windows provides measure of adherence
Time frame: Every day during active beetroot shots (Days 1-7)
Burdensomeness
Follow-up questionnaire will be administered with the online follow-up survey. It explores experience with the best mode of reminder receipt (email or text message), whether the participants guessed their condition, and how burdensome 8 aspects of the study (including daily intake, video recording, upload, questionnaires, physiological assessment) were.
Time frame: 1-3 days after finishing beetroot shots (after final examinations)
Acute stress
Ad-hoc acute stress rating
Time frame: Baseline (non-stress mid point of semester), 1-3 days into active beetroot shots (during final examination period), 4-6 days into active beetroot shots (during final examination period), 1-3 days after finishing beetroot shots (after final examinations)
Cortisol
Cortisol, from saliva sampled with passive drool test
Time frame: Baseline (non-stress mid point of semester), 1-3 days into active beetroot shots (during final examination period), 4-6 days into active beetroot shots (during final examination period)
Perceived stress
Perceived Stress Scale (PSS)
Time frame: Baseline (non-stress mid point of semester), 4-6 days into active beetroot shots (during final examination period)
Mood
Hospital Anxiety and Depression Scale (HADS)
Time frame: Baseline (non-stress mid point of semester), 4-6 days into active beetroot shots (during final examination period)
Blood pressure (systolic and diastolic blood pressure) and heart rate
Measured after at least 10 min of acclimatization to the laboratory
Time frame: Baseline (non-stress mid point of semester), 1-3 days into active beetroot shots (during final examination period), 4-6 days into active beetroot shots (during final examination period)
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