Soluble Corn Fiber Supplementation for Asthma
Soluble Corn Fiber Supplementation for Asthma
Studies of the importance of the human microbiome have demonstrated that microbial
 metabolites of fermentation of our dietary products (e.g. dietary fiber) have a multitude of
 health benefits. The investigators aim to determine whether supplementation of asthmatic
 children with soluble corn fiber alongside standard of care reduces airway inflammation
 driven by the gut microbial metabolites acetate, propionate, or butyrate (short chain fatty
 acids).
Asthma is a complex inflammatory disease of the airways that is estimated to affect 300
 million people worldwide. Incidence of asthma is steadily increasing in Western populations;
 an additional 100 million asthma diagnoses are anticipated by the year 2025. Asthma is a
 multifactorial disease affected by genetic and environmental factors. One major and
 potentially modifiable environmental factor is the Western diet. The Western diet influences
 the microbiome, which in turn, may influence inflammatory airway diseases via a gut
 microbiome-airway connection. The investigators hypothesize that prebiotic dietary fiber
 supplementation leads to increased circulating short chain fatty acid production and
 improvement in asthma disease activity. The investigators will recruit 20 children, ages 6-17
 years old, with asthma from the Severe Asthma Clinic or General Pulmonary Clinic at Phoenix
 Children's Hospital. Participants will be randomly assigned (1:1) using a random number
 generator to ingest PROMOTIR soluble corn fiber (85% fiber, 12 g/day) in a fruit-flavored
 beverage or placebo (malodextrin in a similar fruit-flavored beverage) as previously
 described. Participants will be asked to consume the prebiotic soluble corn fiber (or
 placebo) for 4 weeks alongside their normal diet and normal asthma treatments. Blood will be
 collected pre- and post-fiber intervention to measure baseline and post-intervention
 circulating SCFAs. Stool samples and nasal wash will be collected for microbiome and immune
 analysis pre- and post- fiber consumption. Nasal washes will be collected pre- and post-fiber
 consumption to measure inflammatory patterns.
Inclusion Criteria:

 -  Clinical diagnosis of asthma

 -  Fractional excretion of exhaled nitric oxide (FeNO) > 50 ppb OR a history of
 environmental allergies

 -  No emergency department or hospital visits for asthma in the past 3 months

 -  No systemic corticosteroids in the past 1 month

 -  Ability to consume a liquid drink of SCF or placebo

 -  Ability to return for a 4-6 week follow-up visit

 -  No special or unique diet as determined by PI/CO-Is.

 Exclusion Criteria:

 -  Cystic fibrosis

 -  Bronchiectasis

 -  Change in asthma medicines other than short acting bronchodilators planned over the
 next 4-6 weeks.