Eight weeks of supplementation were associated with a decrease in levels of allergic and pro-inflammatory markers, compared with placebo, according to findings published in the European Journal of Clinical Nutrition .
In addition, the probiotic supplement was found to affect the symptoms of hay fever (allergic rhinitis) with a significant reduction in nasal symptoms in the second month of the study, compared to placebo.
“These findings give two important pieces of information with respect to probiotics and their use for allergic rhinitis,” wrote the researchers. “First that for the beneficial effect of probiotics to manifest on the immune system and allergic symptoms, a continuous 8-week period of oral administration could be required to reach a possible beneficial outcome.
“It is also important to mention here that the study was done during the actual grass pollen season, which makes the effect of the probiotic in our study even more impressive.”
According to the FAO/WHO, probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host".
Led by Anurag Singh, the Lausanne-based scientists recruited 20 people with seasonal allergic rhinitis to participate in their double-blinded, parallel, randomized placebo-controlled trial. Participants were randomly assigned to receive B. lactis NCC2818 or placebo for eight weeks.
Results showed that markers of allergic responses in the blood were lower in the probiotic group, including Th-2 cytokines, compared with the placebo group.
In addition, the researchers also looked at the activation levels of white blood cells that play a role in inflammatory reactions called basophils. Measuring the activation of basophils is a common tool to diagnose allergy. The new study revealed that activation of CD63 basophils was lower in the probiotic group after one month of supplementation, but there no differences between probiotic and placebo after eight weeks.
“The reduction in CD63 expression […] after 4 weeks of administration is reflective of the early impact the probiotic strain B. lactis NCC2818 has on the host immune system,” wrote Singh and co-workers.
“We wanted to conduct the trial during peak seasonal exposure to grass pollen (between May and August) as reflective to the real life situation and investigate if the probiotic strain B. lactis NCC2818 could impact the immune system and have an effect on AR symptoms,” they wrote.
“The fact that in this challenging clinical trial setting, probiotic administration could impact on immunological parameters, mainly Th-2 cytokine levels and basophil activation, and alleviate allergic symptoms compared with placebo treatment suggests that the strain B. lactis NCC2818 should be investigated further in large-scale trials.
“The probiotic field has generally struggled in translating promising in vitro and in vivo findings obtained in preclinical models into health benefits in human intervention clinical trials.
“We feel that the best way forward is to examine the candidate probiotic strains in proof of concept human clinical trials where the focus can be more on investigation of the different immune mechanisms via which a probiotic strain can impact on clinical symptoms, and then based on the findings engage in a subsequent large-scale trial with fewer outcomes and greater statistical power.”
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2012.197
“Immune-modulatory effect of probiotic Bifidobacterium lactis NCC2818 in individuals suffering from seasonal allergic rhinitis to grass pollen: an exploratory, randomized, placebo-controlled clinical trial”
Authors: A Singh, F Hacini-Rachinel, M L Gosoniu, T Bourdeau, S Holvoet, R Doucet-Ladeveze, M Beaumont, A Mercenier, S Nutten
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