Provided is a microbial or probiotic composition which is tailored based on the spectrum of bifidobacteria found in the intestine of at least one individual with secretor blood group phenotype but not commonly found in individuals of non-secretor blood group phenotype. Further provided is a method of tailoring a microbial or probiotic composition based on the bifidobacteria found in the intestine of at least one individual with secretor blood group phenotype but not commonly found in individuals non-secretor blood group phenotype.
