Writing in the journal Vaccine, researchers from Taiwan report that supplements of the probiotic led to an 18 and 17 per cent reduction in the incidence of viral and respiratory infections, respectively, according to a study with about 1,000 children under the age of five.
“This randomized, double-blind study shows that bio-therapeutic agents may be useful in preventing viral and bacterial infectious disease,” wrote lead author Jun-Song Lin from Buddhist Tzu Chi General Hospital in Hualien.
According to the FAO, probiotics are defined as live microorganisms which when administered in adequate amount confer a health benefit on the host. This definition is important, and the Taiwanese researchers do use the term ‘probiotic’ incorrectly.
Working in collaboration with researchers from National Chiao Tung University, Tzu Chi University, and National Dong-Hwa University, Dr Lin recruited 986 children and randomly assigned them to one of four groups: the first received no supplements and acted as the control group, the second group received a daily supplement of L. casei rhamnosus (200 million colony forming units (cfu), Antibiophilus, Laboratoires Lyocentre, France). The third group received daily supplements of L. rhamnosus T cell-1 (10 billion cfu, T Cell-1 Probiotics, Chang Gung Biotechnology Corp, Taipei, Taiwan).
The fourth group received a supplement containing 12 bacterial strains (seven species of Lactobacillus, three types of bifidobacteria, one type of Streptococcus, and one type of Enterococcus).
Significant reductions in bacterial infections were observed in the single strain (1.8 times) and the T-cells 1 (1.92 times) groups, but no reductions were observed in the multiple strain group.
Reductions in gastrointestinal diseases were observed in the multiple strain group, with a 42 and 44 per cent decrease in the short- and long-term. A non-statistically significant reduction in GI disease was also observed in the group receiving L. casei rhamnosus.
Viral infections reduced by 18 per cent in the L. casei rhamnosus group, but no reduction was observed in the multiple probiotic T cell-1 groups.
“This large population study has successfully demonstrated that probiotics could induce differential effects upon infectious disease in preschoolers among the three orally administered commercial probiotics,” wrote the researchers.
When is a probiotic, not a probiotic?
“The efficacy of many commercial probiotics is suspect, due to insufficient growth of various strains in the human intestinal tract, and hardly any probiotic manufacturers have solid evidence to match their claims,” said the Taiwanese researchers.
Furthermore, poor adherence to FAO’s definition is also a problem. Commenting independently on the study, Professor Gregor Reid from the Canadian R&D Centre for Probiotics at the Lawson Health Research Institute, and The University of Western Ontario, told NutraIngredients.com that, although the study is interesting, errors exist in the manuscript
“Unless a strain is designated and shown to confer health benefits in humans, it should not be referred to as probiotic. In the case of the one strain termed L. rhamnosus T cell-1, this is a strange designation, and the journal should have questioned it,” said Prof Reid.
“The name implies that the strain somehow confers an anti-infectious benefit through T cell modulation, yet the study does not examine T cell activation.
“The authors state that "The investigation clearly showed that single strain probiotic supplementation significantly reduced the incidence of bacterial infections by an average of 1.8 times for L. casei rhamnosus and 1.92 times for L. rhamnosus T cell-1". Yet, Figure 3 shows a drop from 0.6 to 0.5 infections per month which is not a 2 fold drop!” added Prof Reid.
Source: Vaccine11 February 2009, Volume 27, Issue 7, Pages 1073-1079“Different effects of probiotic species/strains on infections in preschool children: A double-blind, randomized, controlled study”Authors: J.-S. Lin, Y.-H. Chiu, N.-T. Lin, C.-H. Chu, K.-C. Huang, K.-W. Liao, K.-C. Peng