Probiotics are live bacteria or yeast that is targeted to both healthy individuals and those with chronic medical conditions. Many products make claims that this therapy improves overall health. Unfortunately, proof for many of these claims are lacking. For gastrointestinal disorders, there are indications that probiotics may be helpful in the treatment of a number of acute and
The concept of probiotics (“for life”) was first proposed in the early 1900s. Interest in this form of therapy intensified in the mid-1990s with research into the gut microbiome.
Why should bacteria matter?
The human microbiome (bacteria within the gastrointestinal tract) contains over 500 species of bacteria with a population of nearly 100 trillion bacteria (bacteria outnumber our own human cells 10:1!). These bacteria live in cooperation and competition with each other in the bowel. There is significant evidence that indicates a beneficial effect of these bacteria on gut health. These bacteria also help with the production of nutritional factors, such as B vitamins. Disruption of the host/gut microbial interaction may lead to a number of disease states. This produced the theory that alteration of this gut ecology could lead to improvement in these diseases. The bacteria in probiotics may work through suppressing “bad” bacteria, improving the intestinal barrier, modulating the immune system, and modulating pain perception.
Where do probiotics come from?
Probiotics are derived from food sources. Many of the current products are purified or modified versions of bacteria found in common foods, especially fermented products (dairy).
Current products are available in live, freeze dried, and native form
(most commonly yogurts). Bacteria used in probiotics need to be able to reach the small intestine and colon in sufficient quantities to exert the desired effect.
Other treatment effects seen in smaller trials include: reducing the symptoms of lactose intolerance, managing hepatic encephalopathy (a complication of advanced liver disease), and treatment of pouchitis.
Specific bacteria shown to be of benefit in clinical trials include species of: Lactobacillus, Streptococcus, Saccharomyces, Bifidobacterium, and non-toxigenic Escherichia.
The length of treatment is not known. Previous study has shown that the probiotic strains disappear from the gut within 4 weeks of stopping the probiotics. This suggests that continuous use may be needed.
How should I pick a probiotic?
Probiotic products can vary widely in quality and labeling. Products shown in controlled human studies to be effective (see the list of bacteria and conditions above) should be recommended for use. Probiotics are considered safe in most people, with the possible exception of the critically ill. All probiotic products marketed in the United States are either dietary supplements or foods, with a single product (VSL#3) sold as a medical food. They are typically not covered by insurance.
There is some benefit of probiotics in specific gastrointestinal disorders. These therapies are modest in their effect, and in most cases, are used in combination with other treatments. Probiotics used should be those that have been proven to be effective in achieving the results that they claim. Research and interest in the gut microbiome has intensified and future research will hopefully lead to better use of these natural therapies.