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).