Dietary fibre as a modulator of airway inflammation in asthma

INTERVENTION: 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. CONDITION: Asthma PRIMARY OUTCOME: Plasma short chain fatty acids (SCFA) will be measured before and after each phase of the study. SECONDARY OUTCOME: Airway Inflammation (sputum cell counts, IL‐8, FeNO) Faecal SCFA Systemic Inflammation (Plasma CRP & TNFa) INCLUSION CRITERIA: Doctor diagnosed stable asthma Aged 18+ years Males and Females Never or ex‐smokers (6 months minimum cessation)