Data from 425 people indicated that supplements containing Lactobacillus paracasei subsp. paracasei LP-33 for five weeks were associated with significant improvements in the so-called quality of life for hay fever sufferers who were also taking an antihistamine for their symptoms, compared to antihistamine alone.
While nasal symptoms were unchanged by probiotics, a significant improvement in ocular symptoms was recorded, according to findings published in the European Journal of Clinical Nutrition .
“To our knowledge, this study is the first to show that a probiotic is effective in allergic rhinitis as an add-on therapy to the recommended medicinal treatment,” wrote the researchers.
Hay fever is an allergic reaction to pollen or fungal spores, most commonly grass pollen. According to the American Academy of Allergy Asthma and Immunology, about 60 million people in the U.S. are affected by allergic rhinitis.
The immune system mistakes the spores for harmful invaders and white blood cells - T-helper type 2 (Th2) lymphocytes - produce protein-like cytokines, such as interleukin-4 (IL-4), IL-5 and IL-6, which in turn promote the synthesis of the immune chemicals immunoglobulins (Ig) to bind to the pollen and fight them off.
This is not the first report that probiotic supplements may benefit hay fever symptoms, with scientists from the UK's Institute of Food Research (IFR) reporting last year in PLoS One (doi: 10.1371/journal.pone.0078650) that daily consumption of a drink containing Lactobacillus casei (Yakult) may alter the way our immune cells react to pollen in people suffering from hay fever.
That double-blinded and placebo controlled study did not find, however, that consumption of the Lactobacillus casei Shirota (LcS) probiotic strain did not lead to significant changes in total hay fever symptoms - the primary clinical endpoint of the study.
According to the FAO/WHO, probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host".
Scientists from Montpellier I University (France), University Paris Diderot (France), Copenhagen University Hospital at Gentofte (Denmark), Ruhr-University Bochum (Germany), Biofortis (France), Chr. Hansen A/S (Denmark), and Merck Consumer Health (France), performed a double-blind, placebo-controlled, randomized trial with 425 people with hay fever, and being treated with the anti-histamine loratadine.
Participants were randomly assigned to receive either placebo or the LP-33 supplements for five weeks, and hay fever was assessed using the Rhinitis Quality of Life (RQLQ) global score.
Results showed that decreases in the RQLQ global score were significantly greater in the probiotic group, compared with placebo. While no benefits were observed for nasal symptoms, ocular symptoms were significantly improved in the probiotic group.
While the study confirms data from previous studies on the efficacy of LP-33 to improve quality of life for hay fever sufferers, the researchers stressed that, since probiotics have strain-specific effects, the results cannot be generalized to all probiotics.
“Probiotic foods or food supplements seem to be popular and widely used by subjects suffering from allergic rhinitis, however, a study under real-life conditions and in subjects receiving a medicinal treatment was needed,” they said.
“We believe that our data showing a significant improvement in the QOL of subjects with moderate/severe allergic rhinitis uncontrolled by oral H1-antihistamines is of high relevance, as the disease is recognized as a public health issue in view of its numerous negative effects on day-to-day activities and social life as well as the corresponding economical impact.”
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2014.13
“Efficacy and safety of the probiotic Lactobacillus paracasei LP-33 in allergic rhinitis: a double-blind, randomized, placebo-controlled trial (GA2LEN Study)”
Authors: D J Costa, P Marteau, M Amouyal, L K Poulsen, E Hamelmann, M Cazaubiel, B Housez, S Leuillet, M Stavnsbjerg, P Molimard, S Courau and J Bousquet