Led by researchers from Valio, Finnish scientists report that, despite benefits for kids in day care, no such benefits were observed in the general population. The study was funded by Valio Ltd.
Twenty-eight weeks of supplementation were associated with only 4.7 days per month with respiratory illness, compared to 5.7 days per month in the placebo group, according to findings published in the European Journal of Clinical Nutrition.
According to UNICEF, a global average of 16% of children under five suffer from acute respiratory infections.
The efficacy of probiotics in the prevention of infections in children who attend day care centers has been investigated in several studies, and these have yielded contradictory results. A study from Croatia published in 2009 that found that LGG may decrease the risk of upper respiratory tract infections including rhinitis, pharyngitis, sinusitis, otitis, and the common cold in children attending day care (Clinical Nutrition, Vol. 29, pp. 312-316).
“Long-term consumption of L. rhamnosus GG reduced the occurrence of respiratory illness in children attending day care centers only in the completed cases subgroup analysis based on recovery of GG in fecal samples,” wrote the researchers.
Commenting on the contradictory results in the literature, the researchers said that future studies are needed to further evaluate the links, but that careful screening of the subjects is required before starting the study.
In addition, they recommended careful selection of study country. “Wide availability of GG in a range of products can make the avoidance of GG containing products very challenging for the subjects.
“Dose–response setting to identify the required dose of GG for respiratory symptom reduction in children is also warranted.”
The researchers recruited 523 children aged between 2 and 6 to participate in their 28 week study. The children received either normal milk or the same milk with LGG. According to their analysis, the LGG content of fresh milk was between 0.67 million and 1.9 million colony forming units per milliliter of milk (cfu/ml), while the content in the end-of-shelf life product was between 0.2 million and 1.2 million cfu/ml.
While data from the general population did not show any differences between the placebo and LGG groups for the number of days with respiratory symptoms, the researchers did record observe a reduction of 1 day of symptoms in the LGG group using data from children that showed the presence of LGG in feces.
“Future clinical trials are warranted to clarify the association between fecal recovery of a probiotic and the symptom prevalence.”
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi:10.1038/ejcn.2012.62
“Milk containing probiotic Lactobacillus rhamnosus GG and respiratory illness in children: a randomized, double-blind, placebo-controlled trial”
Authors: M. Kumpu, R.A. Kekkonen, H. Kautiainen, S. Jarvenpaa, A. Kristo, P. Huovinen, A. Pitkaranta, R. Korpela, K. Hatakka