A research article published in this month’s Science Translational Medicine demonstrates that probiotic yogurt does have an effect on gut bacteria. McNulty and colleagues ran two parallel studies using identical human twins and Gnotobiotic mice, i.e. mice with only certain known strains of human gut bacteria in their guts.
They found that although the intake of probiotic bacteria did not change the composition of the human or mouse gut microbiota, it did alter expression of enzymes involved in various metabolic processes, especially involved in the catabolism of plant polysaccharides, an important source of sugars for some bacteria.