Not all lactic acid bacteria are probiotics, ...but some are.

The WHO defines probiotics as: ‘live microorganisms, which when administered in adequate amounts confer a health benefit on the host’, a definition which implies that a beneficial health effect must be demonstrated in human subjects. In October 2009, the European Food Safety Agency (EFSA) issued scientific opinions concerning more than 500 health claim applications; all those concerning probiotics were unfavourable. The EFSA has clearly explained that in nearly all cases, the rejection of a probiotic claim was due to a lack of characterisation of the micro-organism. Unfortunately, the media’s interpretation of the EFSA’s negative response, and subsequently the consumers’ understanding, has been that all probiotics are the same and all are equally ineffective. We would like to correct this misinterpretation and reemphasise that micro-organisms are defined by their genus (for example, Lactobacillus), their species (for example, rhamnosus or johnsonii) and finally their strain name (for example, L. rhamnosus GG (LGG) or NCC533). Inclusion of all lactobacilli in one ‘probiotic group’ is misleading in the same way that the Homo sapiens species should not be confused with other Homo species that have lived on earth; the assertion that the complete Homo genus is responsible for prehistoric drawings and having walked on the moon is, at best, erroneous. The same works for lactobacilli: the fact that a bacterium belongs to a lactobacilli (or bifidobacteria) genus does not alone confer the status of ‘probiotic’. As well as taxonomic considerations, we believe the species and strain levels to be critical when studying the biological effects of probiotic bacteria, and probably the clinical effects that they may elicit. We list below the various arguments that support our position, illustrated by a selection of recent studies on this topic.