Sulfa Drugs? NSAIDS? Who needs ‘em?
I’ve got yoghurt for my IBD!
For those of you amused by the absurdity of such a notion, there may be more to this statement than you might think. With the rapidly growing threat of antibiotic-resistant bacteria, medical researchers have been directing their attention to probiotic therapy as a means of getting the upper hand on the antibiotic dilemma. Probiotic therapy is a relatively new frontier of investigation whereby you ingest living, non-pathogenic bacteria in order to prevent or relieve a variety of human ailments. There is a wide array of probiotic products being marketed as treatments for gastrointestinal diseases including “specially formulated” yoghurts. However, contrary to their claims, studies have demonstrated that many of these products do not have the capacity to exert a significant therapeutic benefit.
Probiotics are the microorganisms normally present in the human gut, or the “flora,” and are essential in maintaining normal gastrointestinal function. Disturbances in the flora itself or the body’s ability to properly interact with the flora have been linked to the pathogenesis of various chronic intestinal disorders. These results have prompted researchers to develop new ways of modifying the complex intestinal ecosystem as a means of therapy and prompted the medical community to step-up its efforts to reduce unnecessary use of antibiotics. Probiotics have particular appeal since the bacterial strains commonly used, Lactobacilli, Bifiobacteria, and Enterococci, are already present in the gut, thus attesting to their relative safety.
Safety is just one of the characteristics of probiotic selection. Other traits that an ideal probiotic would possess in order to better perform their therapeutic role include:
- the ability to survive the harsh travel conditions of the upper GI tract on the way to their site of action,
- the ability to adhere to the epithelial walls of the intestine and colonize,
- the ability to compete with pathogenic microorganisms for nutrients and colonization sites,
- the ability to secrete antibiotic-like substances called bacteriocins, and
- the ability to provide nutritional services via the synthesis of vitamins1.
Other probiotics currently being investigated have also demonstrated an advantageous ability to stimulate the immune system and some have even exhibited anti-cancer effects1. Naturally, it would be difficult to find a single bacterial strain that would exhibit all these qualities. It is for this reason that doctors often administer probiotics in mixtures.
Researchers have reported that one such probiotic mixture, named VSL#3, has demonstrated significant reductions in relapses of pouchitis – an inflammatory condition often occurring after surgical resection of the colon. Gionchetti et al.2 administered 3g of VSL#3 or a placebo twice daily for 9 months to 40 remissive patients diagnosed with chronic pouchitis. A mere 15% of the VSL#3 group relapsed within the trial period compared to 100% of the placebo group. These A similar study later confirmed these results.3
Probiotics have also been investigated for the treatment of ulcerative colitis. A paper by Kruis et al.4 compared the efficacy of the probiotic Escherichia coli strain, Nissle 1917 to the drug mesalazine. Of 222 patients observed for 1 year, 36.4% of the patients receiving the probiotic relapsed compared to 33% of the patients receiving mesalazine. The researchers thus concluded that E. coli Nissle 1917 was therapeutically equivalent to mesalazine in maintaining remission of acute attacks of ulcerative colitis.
Another preliminary study by Ishikawa et al.5 tested the effect of administering 100ml of fermented milk a day to ulcerative colitis sufferers. Eleven patients received milk supplemented with Bifidobacterium and Lactobacilli strains while 10 patients received non-supplemented milk. It was reported that 73% of the patients receiving the probiotics remained in remission compared to 10% of the patients administered the non-supplemented milk that were remissive.
Preliminary clinical data has also suggested that probiotics may be effective in treating Crohn’s disease symptoms. The yeast Saccharomyces boulardii, has been indicated as being effective in preventing or shortening the duration of antibiotic-associated diarrhea in Crohn’s patients6. As well, a study of 28 patients by Malchow et al.7 demonstrated that E.coli Nissle 1917 reduced the rate of relapse in Crohn’s patients by 40% as compared to a placebo.
In addition to these disease specific formulations, consumers now have access to a variety of non-prescription supplements and foods claiming to have probiotic benefits. However, as a study in the UK reported, these claims are often unsupported.8 European food products and supplements were tested for active probiotic cultures and it was found that bacterial numbers fell short of label claims. In a consumer report closer to home, the CBC Marketplace recently aired a story that compared two brands of probiotic supplement capsules. Initial tests showed that both capsules contained over a billion active probiotic cultures per gram (the story suggested that products should contain between one million and one billion cultures per gram to be effective, these numbers are consistent with the doses administered in the controlled scientific studies cited above). However, tests performed two weeks later revealed that the number of active cultures was significantly reduced to concentrations far below the label claims. The Marketplace report also tested 4 brands of yoghurt available in Canada that claim to have added probiotic cultures. Again, most of the products contained over a million active cultures in initial tests but tests performed two weeks later showed dramatic reductions in the number of viable bacteria.
Although some of the yoghurts tested contain over a million living, active, probiotic cultures upon ingestion, these numbers do not guarantee that therapeutic effects or improvements will occur. A study by Wendakoon et al.10 out of the University of Alberta showed that a probiotic yoghurt preparation was ineffective at reducing the number of Helicobacter pylori (the organism commonly associated with duodenal and gastric ulcers) present in the GI tract, despite results indicating that the probiotic cultures were effective at inhibiting H. pylori cultures in vitro (in the laboratory).
While these results may be discouraging for those who are firm believers of probiotic therapy, the true potential of probiotics in GI health has yet to be determined as research in this innovative field is still in its infant stage. As our understanding of the intricate milieu of microorganisms within the human gut deepens, we will be able to further tailor probiotic therapies to be significant and effective alternatives to conventional IBD treatments. As well, probiotic use will benefit from the recent initiatives taken by the UN’s Food and Agriculture Organization and the World Health Organization11 that aim to regulate probiotic use in over the counter supplements and food items. By improving quality assurance procedures and holding manufacturers accountable for the health claims they advertise, pending legislation will provide consumers with a greater confidence in the probiotics they use to improve their overall health.