The WHO (World Health Organization) and the FAO (Food and Agriculture Organization of the United Nations) recommend the use of probiotics for preventing and treating disorders caused by an unbalanced microflora and advise the medical community to consider this application for preventive and therapeutic actions.
It is worth remembering what a probiotic is since, recently, it has been introduced in the food supplements market products that are sold as probiotics, which do not meet the definition given by WHO:
“A probiotic is a living microorganism which, when administered in adequate amounts, confers health benefits to the host”.
In order to classify bacteria as probiotic, it is necessary to provide enough documented scientific evidence on the beneficial health effects because not all bacteria have the same effectiveness, even belonging to the same genus and species. Hence, it is important a perfect characterization of bacterial strains, which allows a correct selection of probiotics.
Let’s take as an example a study on the degree of inhibition of Candida albicans by different individual strains of Bifidobacterium, Lactobacillus, Enterococcus and Lactococcus.
The figure shows that of the 3 strains Bifidobacterium studied (two of B. bifidum and one of B. lactis), only the two strains of B. bifidum presented an inhibition of more than 30% of Candida, but only the strain characterized as B. bifidum W28 inhibited Candida more than 80% when compared to B. bifidum W23 strain.
This study demonstrates also that of the three characterized strains of Lactobacillus acidophilus used (W22, W55 and W74), the strain L. acidophilus W55 did not inhibit the growth of Candida, unlike the characterized strains W22 and W74 did.
Therefore, the characterization allows to highlight the properties of a bacteria, showing that the properties of bacteria X are different from bacteria Y. In addition, the use of well-characterized strains makes that the combination of different bacteria with different properties increase their effectiveness.
It conclusion, multi-strain and multispecies mixtures are much more beneficial than the use of individual bacteria, as these mixtures will act on the three levels of the intestine.