Probiotic Effects on Cold and Influenza-Like Symptom Incidence and Duration in Children

Clinical Study Highlight

Probiotic Effects on Cold and Influenza-Like Symptom Incidence and Duration in Children

Pediatrics Vol. 124 No. 2 August 2009, pp. e172-e179 (doi:10.1542/peds.2008-2666)

Gregory J. Leyer, Shuguang Li, Mohamed E. Mubasher, Cheryl Reifer and Arthur C. Ouwehand

Probiotics may help manage intestinal conditions, but there is less recognition of their value for healthy people who have no intestinal complaint. The ability of probiotics to impact immune function is clearly established; what is less clear is how such effects ultimately impact people’s ability to stay healthy. Immune biomarker studies document a mechanism, but studies with clinical outcomes are necessary to show that the mechanism has relevance.

This double-blinded, randomized, parallel 3-arm study by Leyer et al. showed thatLactobacillus acidophilus NCFM alone or in combination with Bifidobacterium animalissubsp lactis Bi-07, reduced incidence of fever, coughing and rhinorrhea in healthy Chinese children 3–5 years of age.

The dried probiotic was administered to children by mixing into milk at a daily dose of 1010 for 6 months. When both strains were administered together, they each comprised half the total dose. No significant drop in product viability was found over the duration of the study. Products were stored refrigerated at the study site until used, although refrigeration is not stipulated on the commercial product preparations. This product is commercially available under the name “HOWARU Protect,” and is available at levels used in the study in the Evolve Kefir Probiotic Smoothie.

There are many things to praise about this study: adequate power, positive outcomes in a healthy population, characterized strains deposited in an international culture collection, tracking of product stability throughout the study, and providing support for the value of these probiotics during cold/flu season. However, it is of interest that although the study was conducted from November 2005 through May 2006, the study was not registered as a clinical trial until January 2008. Such post hoc registration does not provide assurances of unbiased reporting, regardless of study outcome. Probiotic efficacy research is sometimes criticized for the high number of studies planned, conducted and funded directly by industry. Since limited public funds are available for such research, industry should be lauded, not criticized, for their investments in such research. However, to assuage concerns about bias, it is incumbent upon industry to be as transparent as possible in the conduct of such trials. Important to this process is the registration of clinical trials ( Although trial registration compromises confidentiality, in balance, this practice will do much to elevate the regard for industry-funded studies. In addition, allowing an independent group access to the data to review before publication provides a measure of confidence in the objectivity of reporting.

In summary, this paper provides evidence that these probiotic preparations, administered twice daily, at levels of 1010/day, may help reduce the occurrence of symptoms of fever, coughing and rhinorrhea in young children. Whether or not it is practical to administer a dried probiotic to children of this age twice daily over the course of 6 months is another question that must be considered in application of this research, but clearly the effects were demonstrated.