INFLUENCE OF DIETARY NEOSUGAR ON SELECTED BACTERIAL GROUPS OF THE HUMAN FECAL MICROBIOTA

Despite an increasing awareness of the relationships between the intes tinal microbiota and health, there are few definitive guidelines about dietary interventions to adventitiously influence species composition of the microbiota. Therefore, standard microbiological methods were u sed to determine changes in the abundance of selected bacteria in anae robic faecal samples from ten adult human volunteers who consumed 4g o f neosugar, a mixture of short-chain fructooligosaccharides, daily for 2 wks. The diet was not otherwise controlled. Total anaerobic counts increased or remained relatively stable in nine subjects. The percenta ge of total bacteria counts represented by aerobes increased over ten- fold, but enterics declined by over 90 per cent (from 2.3 per cent to <0.2 per cent). Although bifidobacteria increased from 1.3 per cent to 6.8 per cent of the total bacteria, there was wide individual variati on in responses; bifidobacteria were not detected in two subjects at e ither date (<10(4) colony forming units/g faeces). Lactobacilli increa sed in six of the subjects, but were not a significant component of th e microbiota at either date (<0.0001 per cent). Individual variation i n responses to supplemental neosugar are probably caused by difference s in diet, initial microbiota, and environmental conditions. The resul ts demonstrate that supplementing the diet with neosugar influences th e relative abundances of selected bacteria with some of the changes co nsistent with those considered advantageous.