Dietary fibre as a modulator of airway inflammation in asthma

A randomised crossover trial including clinically stable asthmatic adults to examine the effect of pre/probiotic supplements on short chain fatty acids (SCFA), airway inflammation and to study the mechanisms by which fibre exerts these effects.

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12615000368538

Acronym

FAIM

Enrollment

Registered

2015-04-22

Start date

2015-06-22

Completion date

2015-11-05

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

The purpose of this project is to investigate whether a soluble fibre supplement alone or in combination with a probiotic is able to reduce inflammation in adults with asthma. Once ingested orally, soluble fibre- a normal component of the diet- acts as a prebiotic and is digested by healthy gut bacteria to produce short chain fatty acids (SCFAs). These SCFAs may be beneficial in reducing airway inflammation in asthma. Supplementing with healthy bacteria using a probiotic may also increase the production of SCFAs. The project involves a nine week intervention where 20 subjects with stable asthma will be allocated to take the prebiotic alone, prebiotic with probiotic and placebo supplements for 7 days each, in random order, with a two week washout period between each supplement phase. Subjects will not know which supplement they are receiving throughout the study.

Interventions

There are two intervention arms and one placebo arm in this 3 way cross over study. Each subject will be randomly allocated to take each treatment/placebo arm in random order for 7 days each, with a 2 week wash out period in between each phase of the study. 1. Prebiotic (Frutafit (registered trademark) Inulin powder) (6 gram sachet twice daily) / Placebo capsule (once daily) 2. Prebiotic (Frutafit (registered trademark) Inulin powder) (6 gram sachet twice daily) / Probiotic capsule (Caruso's Alive Probiotic containing: Lactobacillus acidophilus 7.5 billion CFU, Lactobacillus rhamnosus 8.75 billion CFU, Bifidobacterium lactic 8.75 billion CFU) (once daily) Subjects will be provided with 6 grams of Inulin in an individual sachet for each dose, to be mixed with water before meals twice daily (morning/evening). The probiotic provided is in capsule form and is to be taken once daily before breakfast. The placebo capsule is also to be taken once daily before breakfast. Pill count back method and study diaries will be used to monitor adherence. For 2 weeks prior to the first visit and for the duration of the study, participants will consume a fibre-controlled background diet. This will be achieved by avoidance of fibre-rich foods, limiting fruit and vegetable intake to 2 serves/ day and consuming 1/2 cup of All-Bran /day.

Study design

Allocation

Randomised controlled trial

Intervention model

Crossover

Primary purpose

Treatment

Masking

Blinded (masking used) (Subject)

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

Doctor diagnosed stable asthma Aged 18+ years Males and Females Never or ex-smokers (6 months minimum cessation)

Exclusion criteria

Smoking, pregnant/breastfeeding, Asthma is not the primary respiratory diagnosis, Asthma exacerbation or respiratory tract infection (oral corticosteroids or antibiotics) in the past month, Any use of antibiotics in the past month, unable or unwilling to modify diet, diagnosed bowel disorders or intestinal disorders, dietary or nutritional supplement use within the previous 4 weeks, current use of any oral medication known to significantly influence inflammation (eg statins or NSAIDs). Subject has a clinically important medical illness (including serious psychological disorders) likely to interfere with management or participation in the study

Outcome results