A Clinical Trial of Soluble Fiber for Asthma

A Phase II randomized, controlled, clinical trial analyzing the impact of increasing fiber intake and the gut microbiome for children with asthma. If eligible, (determined by inclusions/exclusion criteria as well as fiber intake assess by ASA 24) participants will be put into a fiber (Fruitafit Inulin) or placebo (Maltodextrin) group. Each participant will fil out an Asthma Control Questionnaire (ACQ), collect a nasal wash, and have their blood drawn. Their study medication will be available for them to pick up after their first visit, and they will receive counseling from the Pharmacist on how to implement it into their diet. They will also be sent home with three stool sample kits to be mailed to Northern Arizona University for microbiome and metabolomic analysis. The first kit will be sent within 7 days of their first visit. The second kit will be sent within 14 days (+/- 1 day) of their first visit. The second study visit will occur 25 days (+5 days) after the first visit. All the procedures will be repeated again including taking the ASA 24 questionnaire. The participant will send their final kit within 7 days of completing their last visit. Total study time is approx 30 days. This study is minimal risk which includes risk of fecal contamination, discomfort from collecting specimens, discomfort with answering some of the survey questions, and the risks associated with receiving a blood draw. Participants are compensated for their time and receive a portion of their dietary results. There may not be a direct benefit to the participant, but by participating in this research they may help people in the future with asthma.

• Inulin (Drug), also known as Fruitafit CLR: Soluble tapioca starch from Ingredion.

Primary outcomes

• Alpha diversity. [6 weeks]: A total of 84 participants is required to find significant difference of 54 units of Richness at 90% power with a small effect size. Alpha diversity is used to measure the abundance that individual microbes can be observed. Statistical analysis is used to generate the significance of stool sample diversity as well as how many participants are needed to see the marker.

Secondary outcomes

• Asthma control. [6 weeks]: Assessed via Asthma Control Questionnaire. Scores can range from 0 to 6. With a higher score indicating poor asthma control.
• Gut microbiome composition. [6 weeks]: Analysis of gut microbiome using quantitative polymerase chain reaction (qPCR) and analysis of variance (ANOVA).
• Nasal inflammatory response. [6 weeks]: Measured via quantitative polymerase chain reaction (qPCR).
• Quantification of circulating short chain fatty acids. [6 weeks]: Short chain fatty acids (SCFAs) will be collected and analyzed via microbiome and metabolomic analyses of stool samples and blood serum samples.

Sex: All, ages: 6 Years to 17 Years

Inclusion Criteria:

* Between ages 6-17
* Asthma diagnosis within the last 2 years
* Fractional excretion of exhaled nitric oxide (FeNO) > 50 ppb OR a clinical history of environmental allergies as defined by a positive skin prick or positive specific immunoglobulin E (IgE) tests to aeroallergens
* No emergency department visits in the past 1 month
* Ability to consume a liquid drink of fiber or placebo
* Ability to return for a 4-6 week follow-up visit
* No special or unique diet

Exclusion Criteria:

* Cystic fibrosis
* Bronchiectasis
* Change in asthma medicines other than short acting bronchodilators planned over the next 4-6 weeks
* Baseline estimated daily fiber intake less than or equal to 16 grams as determined by the ASA 24
* Sibling of a participant already enrolled in the study

• Study Protocol and Statistical Analysis Plan (PDF, 2024-01-17)

• Matthew Rank, Principal investigator, Phoenix Children's

NIH grants: U54MD012388