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Scientific Opinion on the substantiation of a health claim related to Lactobacillus casei strain Shirota and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences pursuant to Article 13(5) of Regulation (EC) No 1924/2006

EFSA Journal 2010;8(10):1860 [15 pp.]. doi:10.2903/j.efsa.2010.1860
  EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) Panel Members Carlo Agostoni, Jean-Louis Bresson, Susan Fairweather-Tait, Albert Flynn, Ines Golly, Hannu Korhonen, Pagona Lagiou, Martinus Løvik, Rosangela Marchelli, Ambroise Martin, Bevan Moseley, Monika Neuhäuser-Berthold, Hildegard Przyrembel, Seppo Salminen, Yolanda Sanz, Sean (J.J.) Strain, Stephan Strobel, Inge Tetens, Daniel Tomé, Hendrik van Loveren and Hans Verhagen. One member of the Panel did not participate in the discussion on the subject referred to above because of potential conflicts of interest identified in accordance with the EFSA policy on declarations of interests. Acknowledgment The Panel wishes to thank the members of the Working Group on Claims: Carlo Agostoni, Jean-Louis Bresson, Susan Fairweather-Tait, Albert Flynn, Ines Golly, Marina Heinonen, Hannu Korhonen, Martinus Løvik, Ambroise Martin, Hildegard Przyrembel, Seppo Salminen, Yolanda Sanz, Sean (J.J.) Strain, Inge Tetens, Hendrik van Loveren and Hans Verhagen for the preparatory work on this scientific opinion. Contact nda@efsa.europa.eu
Type: Opinion of the Scientific Committee/Scientific Panel On request from: the Competent Authority of The Netherlands following an application from Yakult Europe B.V. Question number: EFSA-Q-2010-00137 Adopted: 07 October 2010 Published: 18 October 2010 Last updated: 16 June 2011. This version replaces the previous one/s. Affiliation: European Food Safety Authority (EFSA), Parma, Italy
Abstract

Following an application from Yakult Europe B.V., submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of the Netherlands, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver an opinion on the scientific substantiation of a health claim based on newly developed scientific evidence and including a request for the protection of proprietary data related to Lactobacillus casei strain Shirota (LcS) and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences. The food constituent, LcS, which is the subject of the health claim, is sufficiently characterised. The Panel considers that maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences is a beneficial physiological effect. The applicant identified a total of 12 references as being pertinent to the health claim. These included nine human intervention trials and three animal studies. In weighing the evidence, the Panel took into account that there was no human study from which conclusions could be drawn for an effect of LcS consumption on upper respiratory tract infections, that one human study did not support an effect of LcS consumption on the immune response to influenza vaccination, and that there was a lack of evidence for an effect of LcS consumption on the immune system that could relate to the defence of the upper respiratory tract against pathogens. The Panel concludes that a cause and effect relationship has not been established between the consumption of LcS and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences.

© European Food Safety Authority, 2010

Summary

Following an application from Yakult Europe B.V., submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of the Netherlands, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver an opinion on the scientific substantiation of a health claim related to Lactobacillus casei strain Shirota and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences.

The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence and including a request for the protection of proprietary data.

The food constituent that is the subject of the health claim is Lactobacillus casei strain Shirota (LcS). The identification and characterisation of the strain has been performed by applying phenotypic and genotypic methods. The Panel considers that the food constituent, Lactobacillus casei strain Shirota, which is the subject of the health claim, is sufficiently characterised.

The claimed effect is “maintenance of immune defences, including upper respiratory tract defence”. The target population is the general population. The Panel considers that maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences is a beneficial physiological effect.

A total of 12 references, which included nine human intervention studies and three animal studies, were considered to be pertinent by the applicant for either the scientific substantiation of the claim (i.e. maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences) or as supporting evidence for an effect of LcS on the immune system that could relate to the defence of the upper respiratory tract against pathogens.

In a randomised, double-blind, placebo-controlled intervention, 84 endurance athletes were allocated to consume daily either two bottles of fermented milk containing at least 6.5 x 109 CFU of live LcS per bottle or a similar placebo drink without bacteria for 16 weeks during the winter training period. The primary outcome of the study was incidence of upper respiratory tract infections (URTI). Secondary outcomes included severity and duration of URTI episodes, symptoms of gastrointestinal discomfort, and changes in concentrations of several immune markers in biological samples. Subjects were asked to complete weekly a self-administered health questionnaire by rating a series of symptoms as light, moderate or severe. The Panel notes that the questionnaire used was constructed from previously validated questionnaires to assess the incidence of URTI but no information on validation of the specific questionnaire used in the present study was provided. The Panel considers that it has not been shown that this approach provides an appropriate measure of the presence of URTI. A total of 26 subjects (31 %) dropped out during the study. Data analysis was performed in the population of completers only. The Panel considers that the high dropout rate was not taken into account appropriately in the analysis of the data. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim

A randomised, double-blind, placebo-controlled pilot trial was designed to test the feasibility of a daily intervention with two bottles of fermented milk containing at least 6.5 x 109 CFU of live LcS per bottle in an elderly nursing home population. The study report indicates that the study size (n=38 per group) was not adequate to detect significant differences between LcS and placebo groups for incidence of URTI. The Panel agrees that this feasibility study was underpowered to assess the effects of LcS consumption on the incidence of URTI, and that no conclusions can be drawn from this study for the scientific substantiation of the claim.

Subsequent to this pilot study, a multicentre, randomised, double-blind, placebo-controlled trial was conducted in 737 healthy elderly nursing home residents. Subjects were randomly assigned to consume daily two bottles of fermented milk containing at least 6.5 x 109 CFU of live LcS per bottle or a similar placebo drink without bacteria for 176 days. On day 21, all subjects received an influenza vaccine. Primary outcomes of the study were cumulative incidence of upper respiratory tract influenza-like infections and specific IgG antibody levels in serum. Subjects and nursing home staff were asked to record symptoms of running nose, sore throat, fever and cough each day. URTI was defined as the presence of one or more of the symptoms above. The Panel notes that the symptoms used to define the occurrence of URTI (i.e. running nose, sore throat, fever and cough) are non-specific, and that the presence of one or more of these symptoms is not an appropriate measure of the occurrence of URTI in the study population. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claimed effect.

In the same study, the effect of consumption of the LcS drink on the response to influenza vaccination, protective antibody titres, seroconversion and seroprotection rates in the intervention group was compared to the placebo group at days 50 and 176. No significant differences in IgG titres, seroconversion and seroprotection rates between groups were observed. Data were also analysed according to the participants’ ages, taking 80 years as a cut off. The Panel notes that this comparison was not pre-planned in the study protocol and that no scientific justification was provided for it. The Panel considers that this study does not support an effect of LcS consumption on protective IgG titres, seroconversion and seroprotection rates after influenza vaccination in humans.

The remaining publications provided by the applicant reported on effects on the immune system that could relate to the defence of the URT against pathogens. These studies include six human intervention studies and three studies in animal models.

Three double-blind placebo-controlled intervention studies in healthy human subjects investigated the effect of LcS consumption on natural killer (NK) cell activity, among other immune parameters. In one study, no direct comparison between the intervention and placebo group on NK cell activity was provided. The Panel considers that no conclusions can be drawn from this study with regard to effects on the immune system that could relate to the defence of the URT against pathogens. In a second trial a significant increase in NK cell activity and a significantly increased interleukin (IL)-12 synthesis by peripheral blood mononuclear cells were observed ex vivo following the administration of LcS. However, in a third study LcS-fermented milk did not significantly influence several immune markers. The Panel notes that the results from these two studies do not show a consistent effect of LcS consumption on the immune system that could relate to the defence of the URT against pathogens.

One double-blind placebo-controlled study was conducted in subjects with seasonal allergic rhinitis to assess the effects of LcS consumption on antigen-induced IL-5, IL-6 and IFN-γ, specific IgE and specific IgG production. The Panel notes that the evidence provided does not establish that changes in these immune parameters in subjects with seasonal allergic rhinitis are related to the defence of the URT against pathogens in the general population.

The remaining human studies were one-arm, uncontrolled interventions in subjects with human T-cell lymphotropic virus type 1 (HTLV-1) infection and alcoholic liver cirrhosis, respectively. The Panel considers that no conclusions can be drawn from these studies to support an effect of LcS consumption on the immune system that could relate to the defence of the URT against pathogens.

Three studies examined the effects of LcS administration on immune function in animal models. The Panel considers that no conclusions can be drawn from these studies to support an effect of LcS consumption on the immune system that could relate to the defence of the URT against pathogens.

In weighing the evidence the Panel took into account that there was no human study from which conclusions could be drawn for an effect of LcS consumption on URTI, that one human study did not support an effect of LcS consumption on the immune response to influenza vaccination, and that there was a lack of evidence for an effect of LcS on the immune system that could relate to the defence of the URT against pathogens.

The Panel concludes that a cause and effect relationship has not been established between the consumption of Lactobacillus casei strain Shirota and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences.

Keywords

Lactobacillus casei, fermented milk product, upper respiratory tract infections, health claims