CONSUMPTION OF EXOGENOUS BIFIDOBACTERIA DOES NOT ALTER FECAL BIFIDOBACTERIA AND BREATH HYDROGEN EXCRETION IN HUMANS

The hypothesis that consumption of bifidobacteria by humans would incr ease colonic bifidobacteria and decrease breath hydrogen excretion was examined. A commercially available strain of bifidobacteria was track ed through the gastrointestinal tract. We determined that a 12-d feedi ng period of 10(10) cells of exogenous bifidobacteria daily was adequa te to achieve a stable number of exogenous bifidobacteria in the colon . A 12-d washout period was chosen because the exogenous bifidobacteri a could no longer be detected at that time, A double-blind crossover s tudy used both male and female subjects. The order of treatment with s kim milk alone or skim milk + bifidobacteria was randomized. Breath hy drogen excretion (mu mol/L) and fecal counts of total bifidobacteria [ log colony forming units (CFU)/g feces] were not significantly differe nt between males and females and were not affected by consumption of e xogenous bifidobacteria, Calculations based on the numbers of exogenou s bifidobacteria consumed and the fecal numbers of exogenous bifidobac teria excreted suggested that numbers of the exogenous strain increase d within the gastrointestinal tract, These data suggest that it is dif ficult to permanently alter total colonic bifidobacteria and affect ph ysiologic function (net hydrogen in the colon as reflected by breath h ydrogen) by feeding bifidobacteria, although the percentage of the tot al bifidobacteria represented by the exogenous strain can be affected.