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

Despite an increasing awareness of the relationships between the intestinal microbiota and health, there are few definitive guidelines about dietary interventions to adventitiously influence species composition of the microbiota. Therefore, standard microbiological methods were used to determine changes in the abundance of selected bacteria in anaerobic faecal samples from ten adult human volunteers who consumed 4g of 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 percentage 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 variation in responses; bifidobacteria were not detected in two subjects at either date (<10(4) colony forming units/g faeces). Lactobacilli increased in six of the subjects, but were not a significant component of the microbiota at either date (<0.0001 per cent). Individual variation in responses to supplemental neosugar are probably caused by differences in diet, initial microbiota, and environmental conditions. The results demonstrate that supplementing the diet with neosugar influences the relative abundances of selected bacteria with some of the changes consistent with those considered advantageous.