Good News and Bad about Probiotics
According to a review article published in the Canadian Journal of Gastroenterology, appropriately used probiotic supplements have many potential health benefits with little risk of side effects.1
Probiotics are nutritional supplements containing live bacterial or yeast cultures. Among the many different types of probiotics available, the most common include a strain of bacteria known as Lactobacillus acidophilus and a strain of yeast known as Saccharomyces boulardii.
Some individuals may harbor abnormal and potentially disease-promoting intestinal bacteria, caused by digestive disturbances or certain dietary patterns, because their "good" bacteria have been killed by antibiotics, or for unknown reasons. Probiotics are recommended by some doctors in order to repopulate the intestinal tract with “friendly” organisms. However, the way in which probiotics work is actually more complicated than merely "setting up shop" in the intestines. In fact, the most commonly used strains of probiotics are not thought to be able to survive in the intestine. Just how these organisms do exert their beneficial effects therefore remains, in large part, a mystery to researchers.
Probiotics have several well-established clinical uses. Most notably they prevent gastrointestinal distress in patients taking antibiotics.2 In particular, supplements made from yeast have been shown to prevent life-threatening diarrhea in critically ill patients taking antibiotics.3 Some, but not all, evidence suggests that probiotics may be useful for the treatment of non-antibiotic associated infectious diarrhea, as well.4
In addition to their use in the prevention and treatment of acute diarrhea, probiotics may be useful for the treatment of certain chronic diseases. Various probiotic supplements have shown benefit in clinical trials as a treatment for inflammatory bowel disease (both ulcerative colitis and Crohn’s disease).5 6 In addition, animal and test-tube studies suggest that long-term use of probiotic supplements may help prevent colon cancer.7
The clinical trials showing the most beneficial results in most of these conditions used either Lactobacillus GG at a dose of 10,000,000,000 (10 billion) organisms per day or Saccharomyces boulardii at one gram per day.8
Probiotic supplements are generally considered safe for use by healthy people. In fact, in 143 studies that included a total of over 7,500 participants, no serious adverse effects of probiotics have been noted.9 However, people at risk of immune suppression should consult a physician before taking probiotics, as there is a potential risk of serious infection with their use.10
The downside of probiotics is that the consumer is often not getting what the supplement label promises. A 1999 study found that of over 50 probiotic supplements tested, most contained far fewer live organisms than the label claimed.11 More importantly, many contained bacterial contaminants that had potential health risks. There is currently no standardization of these types of products in the United States, and therefore no guidelines beyond clinical experience to differentiate a good from a bad product.
1. Madsen KL. The use of probiotics in gastrointestinal disease. Can J Gastroenterol 2001;15:817–22.
2. Loizeau E. Can antibiotic-associated diarrhea be prevented? Ann Gastroenterol Hepatol 1993;29:15–8 [in French].
3. Bleichner G, Blehaut H, Mentec H, Moyse D. Saccharomyces boulardii prevents diarrhea in critically ill tube-fed patients. A multicenter, randomized, double-blind placebo-controlled trial. Intensive Care Med 1997;23:517–23.
4. Madsen KL. The use of probiotics in gastrointestinal disease. Can J Gastroenterol 2001;15:817–22.
5. Kruis W, Schutz E, Fric P, et al. Double-blind comparison of an oral Escherichia coli preparation and mesalazine in maintaining remission of ulcerative colitis. Aliment Pharmacol Ther 1997;11:853–8.
6. Plein K, Hotz J. Therapeutic effects of Saccharomyces boulardii on mild residual symptoms in a stable phase of Crohn’s disease with special respect to chronic diarrhea—a pilot study. Z Gastroenterol 1993;31:129–34.
7. Burns AJ, Rowland IR. Anti-carcinogenicity of probiotics and prebiotics. Curr Issues Intest Microbiol 2000;1:13–24.
8. Madsen KL. The use of probiotics in gastrointestinal disease. Can J Gastroenterol 2001;15:817–22.
9.Madsen KL. The use of probiotics in gastrointestinal disease. Can J Gastroenterol 2001;15:817–22.
10. Bassetti S, Frei R, Zimmerli W. Fungemia with Saccharomyces cerevisiae after treatment with Saccharomyces boulardii. Am J Med 1998;105:71–2.
11. Hamilton-Miller JM, Shah S, Winkler JT. Public health issues arising from microbiological and labelling quality of foods and supplements containing probiotic microorganisms. Public Health Nutr 1999;2:223–9.
Matt Brignall, ND, is in practice at the Seattle Cancer Treatment and Wellness Center and at the Evergreen Integrative Medicine Clinic in Kirkland, WA. He specializes in integrative treatment of cancer. He is a contributor to Healthnotes and Healthnotes Newswire.
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