Probiotics. Some evidence of their effectiveness

To define the term probiotics, to indicate how to identify products that have been proven beneficial, and to assess the quality of evidence regarding probiotics.

A few level I studies support the effectiveness of specific probiotics for certain diagnoses. For most so-called probiotics, however, weak or no evidence supports their effectiveness.

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Level I evidence supports use of VSL#3 for maintaining remission of inflammatory colitis. Probiotics for treating vaginal infections, Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14, have level I evidence of effectiveness, but are not available in Canada. Specific probiotics taken for certain indications improve health and have few side effects.

Limited but good evidence supports the role of certain probiotics in medical practice. Because consumer pressure will undoubtedly stimulate further interest in probiotics, family doctors need to be informed about them so they can advise their patients appropriately.