Probiotics and gastrointestinal health.

Evidence for positive health benefits of Lactobacilli applies to only a few strains used for commercial applications. It is generally agreed that a probiotic must be capable of colonizing the intestinal tract to influence human health; this requirement disqualifies many of the strains currently used in fermented dairy products. Lactobacillus GG, a variant of L. casei sps rhamnosus, has been studied extensively in adults and children. When consumed as a dairy product or as a lyophilized powder, LGG colonizes the gastrointestinal tract for 1-3 days in most individuals and up to 7 days in about 30% of subjects. Traveler's diarrhea, antibiotic-associated diarrhea, and relapsing Clostridium difficile colitis are improved with LGG. In infantile diarrhea, the severity and duration of the attack is reduced. LGG-fermented milk lessens the intestinal permeability defects caused by exposure to cows milk or rotavirus infection. LGG has proven beneficial effects on intestinal immunity. It increases the numbers of IgA and other immunoglobulin-secreting cells in the intestinal mucosa. LGG stimulates local release of interferon. It facilitates antigen transport to underlying lymphoid cells, which serves to increase antigen uptake in Peyer's patches. LGG also acts as an immunoadjuvant for oral vaccines. In an animal model of colon cancer, LGG reduced the incidence of chemically induced tumors in the large bowel of rodents. Extensive safety testing has shown no pathogenic potential in humans or animals. Probiotic cultures of Lactobacilli have the potential to bring substantial health benefits to the consumer. The purported benefits for any probiotic must pass the highest standards of scientific scrutiny before the claims can be accepted.