Long-term ingestion of lactosucrose increases Bifidobacterium sp. in human fecal flora

We investigated the influence of lactosucrose on the intestinal flora of healthy volunteers. Eight healthy volunteers (male:female = 4:4, age 34 +/- 4 years) received 6 g of lactosucrose daily for 8 weeks. Fecal microflora, bacterial metabolites, pH, and moisture were analyzed before and after the administration of lactosucrose. The results showed that the number and percentage of Bifidobacterium sp. in relation to the total bacteria significantly increased during the period of lactosucrose administration. Although fecal putrefactive products, fatty acids, pH, moisture content, and stool volume did not show significant changes during the test period, the amount of fecal phenol showed a negative correlation with the number of Bifidobacterium sp. Fecal ammonia significantly decreased after 4 and 8 weeks of lactosucrose administration, and 1 week after the end of lactosucrose administration, compared with results after a 1-week administration of lactosucrose. When the administration was stopped, the percentage of Bifidobacterium sp. in relation to the total count gradually decreased to the same level as before the administration of lactosucrose. These results suggest that under physiological conditions, lactosucrose acts on the intestinal microflora as a growth factor of Bifidobacterium sp.