Clinical Research – Improving Seasonal Allergies with Probiotics
Reviewed by: Alan Gaby, M.D.
Author: Dennis-Wall JC, et al
Reference: Probiotics (Lactobacillus gasseri KS-13, Bifidobacterium bifidum G9-1, and Bifidobacterium longum MM-2) improve rhinoconjunctivitis-specific quality of life in individuals with seasonal allergies: a double-blind, placebo-controlled, randomized trial. Am J Clin Nutr 2017;105:758-767.
Design: Randomized, double-blind, placebo-controlled trial.
Participants: One hundred seventy-three otherwise healthy individuals (mean age, 27 years) with seasonal allergic rhinoconjunctivitis.
Study Medication and Dosage: Two capsules per day of a probiotic preparation (KyoDophilus; Wakanuga of America Co., Ltd.) or placebo during the spring allergy season for 8 weeks. Each capsule provided 1.2 billion colony-forming units (CFU) of Lactobacillus gasseri KS-13, 0.15 billion CFU of Bifidobacterium bifidum G9-1, and 0.15 billion CFU of B. longum MM-2.
Primary Outcome Measure: Symptom severity, as determined by the score on the Mini Rhinoconjunctivitis Quality of Life Questionnaire.
Key Finding: Compared with placebo, the probiotic significantly improved the mean score on the Mini Rhinoconjunctivitis Quality of Life Questionnaire (p < 0.05). The mean improvement attributable to the probiotic (i.e., the difference between probiotic and placebo) was 0.49 points on a 6-point scale (with 0 indicating not troubled and 6 indicating extremely troubled).
Practice Implications: In this study, a commercially available probiotic preparation produced a small but statistically significant improvement in symptoms of seasonal allergic rhinoconjunctivitis. The mechanism of action of the probiotic is not known. The study was funded by the company that manufactures and sells Kyodophilus; however, none of the study authors declared a conflict of interest.