Healthy Eating Better Breathing: A Feeding Study in Patients With Asthma

Study Overview
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Brief Summary
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The study is a randomized, crossover meal-replacement pilot intervention to determine feasibility of a larger scale dietary trial in asthma and gather preliminary evidence for the impact of a healthy diet on asthma outcomes. Participants with doctor-diagnosed asthma were randomized to crossover trial of a 4-week dietary intervention or usual diet with a 4-week washout period. During the dietary intervention, all meals and snacks were provided by the study.

Detailed Description
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The objective of the study is to demonstrate feasibility of a randomized, controlled clinical trial of a dietary intervention in a population of adults with asthma and to determine sample size estimates for a larger, more definitive trial aimed at improving asthma clinical outcomes and improving markers of inflammation and oxidative stress. The study uses a feeding trial design comprised of a 4 week dietary intervention in which all meals are provided to study participants and a 4 week control diet comprised of usual dietary intake. Participants are randomized to the intervention or control diet and then cross over to the alternate assignment after a 4 week washout period.

Official Title
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Dietary Interventions in Asthma Treatment:Healthy Eating Better Breathing Asthma Diet Pilot Study

Conditions
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Asthma

Intervention / Treatment
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* Other: healthy diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ages 18-50, self-reported physician diagnosis and treatment for asthma within the 12 months prior to enrollment, stable asthma defined as no asthma exacerbation (emergency department visit, systemic steroid treatment, or urgent care visit) or respiratory infection in the 4 weeks prior to enrollment. Exclusion Criteria: active smokers,pregnant or breastfeeding, using systemic corticosteroids or warfarin, had another major pulmonary diagnosis or significant systemic illness, reported excessive alcohol consumption (over 14 drinks per week or six or more drinks on one or more occasions per week), reported food allergy, or weighed over 350 pounds or changed weight by over ten pounds in the two months prior to screening

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: healthy diet<br>Participants were provided all meals and snacks for four weeks. Menus were created to target a healthy diet high in unsaturated fats. | Other: healthy diet<br>* Participants were provided meals and snacks for one month that represented a healthy diet that is high in unsaturated fats, approximating a Mediterranean diet<br>|
| No Intervention: control diet<br>Participants were instructed to consume their usual diet. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Feasibility as assessed by the number of participant drop outs | Feasibility will be assessed by the number of drop outs. | Change from baseline and 4 weeks | 
| Adherence using 24 hour diet recall | Adherence to the dietary intervention will be assessed using self-report of dietary intake via 24 hour dietary recall. | Change from baseline to 4 weeks | 
| Adherence assessed by serum carotenoids | Serum carotenoids will be measured at baseline and at 4 weeks. An increase in serum carotenoids is expected with adherence to the dietary intervention. | Change from baseline to 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| FEV1 | Spirometry will be measured according to the American Thoracic Society standards. The forced expiratory volume in one second (FEV1) will be assessed and compared between baseline and 4 weeks after the dietary intervention | Difference between baseline and 4 weeks | 
| FEV1 | Spirometry will be measured according to the American Thoracic Society standards. The forced expiratory volume in one second (FEV1) will be assessed and compared between baseline and 2 weeks after the dietary intervention | Difference between baseline and 2 weeks | 
| FVC | Spirometry will be measured according to the American Thoracic Society standards. The forced vital capacity (FVC) will be assessed and compared between baseline and 4 weeks after the dietary intervention | Difference between baseline and 2 weeks | 
| FVC | Spirometry will be measured according to the American Thoracic Society standards. The forced vital capacity (FVC) will be assessed and compared between baseline and 4 weeks after the dietary intervention | Difference between baseline and 4 weeks | 
| FEV1/FVC ratio | Spirometry will be measured according to the American Thoracic Society standards. The forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio will be assessed and compared between baseline and 4 weeks after the dietary intervention | Difference between baseline and 4 weeks | 
| FEV1/FVC ratio | Spirometry will be measured according to the American Thoracic Society standards. The forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio will be assessed and compared between baseline and 2 weeks after the dietary intervention | Difference between baseline and 2 weeks | 
| Asthma status | Asthma Control Test (ACT, range 5-25, higher score denoting better asthma control). The change in score between baseline and week 4 will be assessed. | Difference between baseline and 4 weeks | 
| Asthma status | Asthma Control Test (ACT, range 5-25, higher score denoting better asthma control). The change in score between baseline and week 2 will be assessed. | Difference between baseline and 2 weeks | 
| Asthma Symptom Utility Index | Asthma Symptom Utility Index (ASUI, range 0-1, higher score denoting fewer symptoms) will be measured and the difference between week 4 and week 0 will be assessed. | Difference between baseline and 4 weeks | 
| Asthma Symptom Utility Index | Asthma Symptom Utility Index (ASUI, range 0-1, higher score denoting fewer symptoms) will be measured and the difference between week 2 and week 0 (baseline) will be assessed. | Difference between baseline and 2 weeks | 
| Asthma Quality of Life Questionnaire (AQLQ) | Asthma Quality of Life Questionnaire (AQLQ) is a 32 item questionnaire and each question uses a 7-point Likert scale (7 = not impaired at all; - 1 = severely impaired). Scores between week 0 (baseline) and week 4 will be assessed. | Difference between baseline and 4 weeks | 
| Asthma Quality of Life Questionnaire (AQLQ) | Asthma Quality of Life Questionnaire (AQLQ) is a 32 item questionnaire and each question uses a 7-point Likert scale (7 = not impaired at all - 1 = severely impaired). Scores between week 0 (baseline) and week 2 will be assessed. | Difference between baseline and 2 weeks | 
| Exhaled nitric oxide | Exhaled nitric oxide is an indicator of airway inflammation and will be measured according to American Thoracic Society standards at baseline and 4 weeks. | Difference between baseline and 4 weeks | 
| Exhaled nitric oxide | Exhaled nitric oxide is an indicator of airway inflammation and will be measured according to American Thoracic Society standards at baseline and 2 weeks. | Difference between baseline and 2 weeks | 
| Adherence assessed by serum carotenoids | Serum carotenoids will be measured at baseline and at 4 weeks. An increase in serum carotenoids is expected with adherence to the dietary intervention. | Difference between baseline and 2 weeks |