Bifidobacteria are a form of "friendly" bacteria which operate in the lower part of the digestive system. They help to release energy and nutrients from food. It is thought that IBS (Irritable Bowel Syndrome) may be related to an imbalance of gut bacteria. Bifidobacteria provides the functions of converting carbohydrate into lactate inside the intestine. Lactate is an acidic substance, which provides an acidic medium to suppress the growth of harmful bacteria. Moreover, bifidobacteria generates two chemicals, organic acid and bifidin. They act as antibiotic to inhibit harmful bacterial activity. Bifidobacteria is also beneficial to human health by regulating digestive and physical states of intestine. This is why so important to maintain the bifidobacterial activity especially during the course of aging.
In the human large intestine bifidobacteria are a numerically important group of micro-organisms which are considered to exert a range of biological activities related to host health. One aspect is the inhibitory effect of these bacteria on other species, possibly excluding long term colonization by invasive pathogens. It has been suggested that the mechanism of inhibition carried out by bifidobacteria is related to the fermentative production of acids such as acetate and lactate.
Bifidobacteria are dominant in the gut of full-term infants, although colonisation by them is often delayed in preterm neonates. Bifidobacteria are recognised to have beneficial effects on digestive disorders and they might prevent neonatal necrotising enterocolitis (NEC), a gastrointestinal disease that predominantly affects premature infants. They have been shown to protect gnotobiotic quails against NEC-like lesions when the birds were inoculated with faecal flora from preterm infants, decreasing the clostridial population. The present study was designed to investigate whether oligofructose, which stimulates the activity of bifidobacteria, may enhance their protective role.