Probiotics are foods or products which contain enough living bacteria to change a person’s natural gut bacterial balance. They may change the immune system and remove pathogens from the gut. Many studies have been done which show that probiotics have a role in the prevention and treatment of a wide range of gastrointestinal diseases. There is evidence that bacterial imbalance in the intestines is responsible for gastrointestinal diseases with chronic and recurrent inflammation.

This meta-analysis was done to determine whether probiotics worked better or worse than standard treatments for 8 different gastrointestinal diseases using 11 different species or mixtures of probiotics. Also, the authors assessed whether the probiotic dose, length of treatment, and age of patients were important. A literature search was done of studies on probiotics in prevention and treatment of gastrointestinal diseases. A total of 84 studies were found and researched.

The probiotics used included Lactobacillus casei*, L. plantarum, L. acidophilus, L. delbrueckii subsp. Bulgaricus, Bifidobacterium longum, B. breve, B. infantis, Streptococcus salivarius subsp., S. boulardii, E. faecium, and C. butyricum. Some of these were used in combination. The eight different gastrointestinal diseases were: irritable bowel syndrome, Helicobacter pylori infection, necrotizing enterocolitis, pouchitis, antibiotic-associated diarrhea, Clostridium difficle disease, infectious diarrhea, and traveler’s diarrhea.

The result was that 37% of the studies revealed significant improvement if patients were treated with a probiotic. Across all GI diseases and all probiotics, the use of probiotics was effective. Those used in combination appeared to be effective. When used alone, L. acidophilus**, L. plantarum, and B. infantis weren’t significantly effective. VSL #3 is a combination of probiotics and was shown to be effective.

Probiotics seemed to work equally well across all age groups, including infants, children, and adults. The dose level did not seem to be important. Longer treatment periods (9-240 weeks) gave better results than shorter periods (3-4 weeks). No differences were seen between the benefits from single probiotics versus mixed probiotics.

Antibiotic-acquired diarrhea was shown to be preventable by use of probiotics while the patient is on antibiotics. Probiotics were shown to significantly improve inflammatory bowel syndrome. There has even been a suggestion that probiotics increase the eradication rates of H. pylori. Necrotizing enterocolitis was the only condition that did not seem to respond to probiotics.

CONCLUSION: Probiotics can work quite well for treatment and prevention of a number of gastrointestinal diseases. The number of organisms in the dose do not seem to be as important as the length of treatment. It is becoming apparent that the strain of the probiotic may be as important as the genus and species. Single probiotics worked as well as mixtures of several bacteria.

NOTES: *The Latin names include the capitalized genus and the non-capitalized species. There can be subspecies or strains.

**Lactobacillus acidophilus was not found to be effective unless it was defined as Lactobacillus acidophilus PB, which is effective for traveler’s diarrhea.

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PMID: 22529959.

Summary #751.