Breakthrough research has recently shed light on the molecular mechanisms responsible for how probiotic ingredients work. A group of international researchers has discovered how helpful bacteria interact with the human gut where they confer their health giving properties. This new study has opened up a whole fresh field of research that clarifies the mode of action of live microorganisms contained in probiotic foods. Good news, perhaps, for the manufacturers of probiotics in the light of recent rejection of some of their claims by the EU.
The European Food Safety Authority’s (EFSA) dismissal of 171 of the 181 dossiers submitted to them by probiotic food manufacturers (who were looking to have product health claims endorsed) came as a big disappointment. The dossiers submitted by some of the world’s biggest suppliers of probiotic foods were rejected on the grounds that the probiotic strains in question had not been sufficiently characterised. According to EFSA, the microorganisms involved in the health giving (probiotic) benefits of a product should be sufficiently characterisated at the strain level by internationally accepted genetic methods. EFSA has also shown its preference for human studies to validate any health claims (rather than in vitro cell models). In particular, EFSA has stated that claims need to be “sufficiently defined” in order that the effect of the probiotic ingredient could be subjected to tests and measurements using generally accepted techniques.
The results of the international study may well provide some support to probiotic companies struggling to get their products validated. The research team led by scientists at the University of Helsinki and incorporating researchers from the Finnish dairy company Valio, started by sequencing the whole genome of the most frequently used and studied probiotic Lactobacillus rhamnosus GG (LGG), as well as other closely-related bacteria. The researchers then went on to isolate the genetic sequences (and hence the proteins) responsible for LGG binding to mucus in the human intestine. The proteins identified form the ‘pili’ of the bacteria; long ‘hairlike’ appendages 1-10 nm in diameter that stick out from the cell surface and are used in host-cell attachment. One of the proteins forming a subunit of the pili was shown to provide a clear interaction with the human gut. This binding mechanism is thought by the scientists to be responsible for the health promoting effects of LGG and other probiotic bacteria.
The results, which have been published in the respected PNAS research journal, not only illustrate how probiotics may be involved in gut/protein interactions but, it is hoped, go on to promote product development in the food industry. However, the first hurdle is to get the health claims of probiotics approved at the European level. Studies such as this, which provide a positive example of cooperation between the food industry and academia are a good start. By knowing the full genetic sequence of a probiotic bacteria, manufacturers will have more tools in their arsenal to provide the genetic markers that can be used to identify bacteria in a product. And having a better idea of how probiotics work at the molecular level can only help to bolster any new product dossier submitted to EFSA. In addition, this new knowledge will help companies refine their scientific arguments when they finally come to resubmit their dossiers to the food authority.
