Original Article

European Journal of Clinical Nutrition (2014) 68, 602–607; doi:10.1038/ejcn.2014.13; published online 26 February 2014

Food and health

Efficacy and safety of the probiotic Lactobacillus paracasei LP-33 in allergic rhinitis: a double-blind, randomized, placebo-controlled trial (GA2LEN Study)

D J Costa1, P Marteau2, M Amouyal1, L K Poulsen3, E Hamelmann4, M Cazaubiel5, B Housez5, S Leuillet5, M Stavnsbjerg6, P Molimard7, S Courau7 and J Bousquet8,9

  1. 1Primary Care Department, University of Medicine, Montpellier I University, Montpellier, France
  2. 2University Paris Diderot, Sorbonne Paris Cité, APHP, Department of Hepato-gastro-enterology, Hôpital Lariboisière, Paris, France
  3. 3Allergy Clinic, Copenhagen University Hospital at Gentofte, Copenhagen, Denmark
  4. 4University Children’s Hospital, Ruhr-University Bochum, Department of Pediatrics, Bochum, Germany
  5. 5Biofortis, Mérieux NutriSciences Company, Saint-Herblain, France
  6. 6Global Regulatory and External Affairs, Chr. Hansen A/S, Hørsholm, Denmark
  7. 7Merck Consumer Health, Merck Médication Familiale, Dijon, France
  8. 8Department of Respiratory Diseases, University Hospital, Hôpital Arnaud de Villeneuve, Montpellier, France
  9. 9Inserm, CESP Centre for Research in Epidemiology and Population Health, Respiratory and Environmental Epidemiology team, Villejuif, France

Correspondence: Professor J Bousquet, Service Maladies Respiratoires, Hôpital Arnaud de Villeneuve, 34295 Montpellier Cedex 5, France. E-mail: jean.bousquet@inserm.fr

Received 2 May 2013; Revised 2 November 2013; Accepted 29 November 2013
Advance online publication 26 February 2014





An imbalance between Th1 and Th2 cells is involved in allergic rhinitis (AR) that may be improved by probiotics. To test the efficacy of the probiotic Lactobacillus paracasei subsp. paracasei LP-33, a double-blind, placebo-controlled, randomized trial was carried out in patients with AR to grass pollen treated with loratadine and presenting altered quality of life.



Subjects with persistent AR, symptomatic during the grass pollen season, and a positive skin test or specific immunoglobulin E to grass pollens were included by general practitioners (GPs). All received loratadine for 5 weeks. The primary end point was the improvement in Rhinitis Quality of Life (RQLQ) global score at the fifth week of LP-33 consumption compared with placebo (in addition to loratadine). Secondary end points included nasal and ocular symptoms (individual and total symptom scores), visual analogue scale and time of first exacerbation of the symptoms when loratadine was stopped.



A total of 425 subjects were included. Using intent-to-treat analysis, the RQLQ global score decreased significantly more in the LP-33 group than in the placebo group (P=0.0255, difference=−0.286 (95% confidence interval (CI): −0.536; −0.035)). No significant differences were noted for the change of the rhinitis total symptom score 5 global score between groups (P=0.1288, difference=−0.452 (95% CI: −1.036; 0.132)). Significant differences in ocular symptoms (RQLQ) were observed between groups (P=0.0029, difference=−0.4087 (95% CI: −0.6768; −0.1407)).



This study performed by GPs shows that LP-33 improves the quality of life of subjects with persistent AR who are currently being treated with an oral H1-antihistamine. Whereas nasal symptoms had not changed, ocular symptoms had consistently improved.

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