Dietary Interventions in Asthma Treatment: Sprouts Study

Not Applicable

Terminated

Brief Summary: Sulforaphane (SFN) is a naturally occurring isothiocyanate that is a potent inducer of Phase II enzymes which play a critical role in preventing oxidative stress (via activation of Nrf2). Broccoli sprouts (BS) contain the richest source of SFN.

The main objectives of this study are to test the effect of broccoli sprouts (BS) on biomarkers of oxidative stress (OS), inflammation, basophil activation, and clinical outcomes in mouse allergen-induced asthma by (1) determining if BS improves lung function and airways symptom responses in mouse-sensitized adults with asthma undergoing environmental mouse allergen challenge (EMAC), (2) examining the effect of BS on OS, inflammation, and basophil activation, and (3) examining the effect of BS on changes in OS, inflammation, and basophil activation after EMAC.

Detailed Description: After eligibility is confirmed, participants will be randomized to (a) placebo then BS or (b) BS then placebo. At randomization, baseline exhaled nitric oxide (eNO), forced expiratory volume at one second (FEV1), nasal epithelial gene expression, urinary OS biomarkers, serum inflammatory and OS biomarkers, and basophil activation will be assessed. These will be assessed again after 7 days on the assigned intervention at two time points: pre- and post-EMAC. The 1 week time period was chosen because previous studies have shown that daily ingestion of a broccoli sprout homogenate for three days resulted in upregulation of phase II enzyme gene expression in nasal epithelial cells. Following a 2-week washout period, this protocol will be repeated for the second intervention, phase II. The 2 week washout period will be sufficient as the half life of the extract of the active ingredient in broccoli sprouts, SFN, has been shown to be 1.8 hours.(16) Participants' diets will be assessed before and after each intervention with a Food Frequency Questionnaire and a questionnaire to capture intake of specific foods that are rich in SFN.

Recruitment & Eligibility

Inclusion Criteria

Age 18-49 years
Physician-diagnosed asthma
No other major pulmonary disease such as cystic fibrosis or chronic obstructive pulmonary disease (COPD)
Mouse sensitization, defined by a positive skin prick test to mouse epithelial extract or positive mouse-specific immunoglobulin E (IgE)
Non-smoker

Exclusion Criteria

Severe or unstable asthma defined as requiring hospitalization in the previous year or intubation in the previous 2 years, or on high-dose inhaled corticosteroids or chronic oral corticosteroids
Baseline FEV1 and FEV1/forced vital capacity (FVC) < 70% predicted
Positive skin prick test (SPT) to a pet currently living in the participant's home
Other significant medical issues such as heart disease or poorly controlled hypertension, or hypothyroidism
Pregnancy or nursing/breastfeeding mothers
On beta-blocker therapy
Taking anti-oxidant supplements
Unable to stop antihistamines prior to skin testing
Unable to stop medications that may interfere with allergen challenge responses prior to challenges.
The participant has food allergy to BS or AS.
Omalizumab use within the last 12 months.
Oral corticosteroid use within the last 2 weeks.

Arm && Interventions

Group	Intervention	Description
Broccoli Sprouts, then Alfalfa Sprouts	Alfalfa Sprouts	Broccoli Sprout sandwich/wrap will be eaten daily for 7 consecutive days followed by alfalfa sprouts after washout.
Alfalfa Sprouts, then Broccoli Sprouts	Broccoli Sprouts	Alfalfa Sprout sandwich/wrap will be eaten daily for 7 consecutive days followed by broccoli sprouts after washout.
Broccoli Sprouts, then Alfalfa Sprouts	Broccoli Sprouts	Broccoli Sprout sandwich/wrap will be eaten daily for 7 consecutive days followed by alfalfa sprouts after washout.
Alfalfa Sprouts, then Broccoli Sprouts	Alfalfa Sprouts	Alfalfa Sprout sandwich/wrap will be eaten daily for 7 consecutive days followed by broccoli sprouts after washout.

Primary Outcome Measures

Name	Time	Method
Change in Forced Expiratory Volume at One Second (FEV1)	30 days	The percentage change in FEV1 from the pre-challenge FEV1 value over the 1 hour mouse chamber exposure.

Secondary Outcome Measures