Quality of Probiotic Supplements Questioned
People who take supplements that are supposed to contain beneficial bacteria (probiotics) may not be getting their money’s worth, according to a study presented by researchers from Bastyr University (Kenmore, WA) at an American Public Health Association meeting. The finding that some of these products do not contain viable bacteria or are contaminated with other potentially harmful bacteria raises concerns about the safety and efficacy of these products.
The intestinal tract contains billions of beneficial bacteria that perform various necessary functions, such as aiding in the digestion and absorption of food and protecting the body against microorganisms that can cause infection. While there are dozens of different types of friendly bacteria, Lactobacillus acidophilus, L. bulgaricus, L. thermophilus, L. reuteri, and Bifidobacterium bifidum are some of the more common strains found in the gut. Studies suggest that taking supplements containing these bacteria can help boost immune function and prevent or relieve certain health conditions including irritable bowel syndrome, vaginal yeast infections, and traveler’s diarrhea. However, commercially available probiotic products that do not contain what they are purported to contain will not deliver these benefits.
According to this new report, laboratory testing of 12 refrigerated and 8 non-refrigerated, randomly selected probiotic supplements obtained from different health food stores revealed that only one product contained the same bacteria as those listed on the label. Many of the refrigerated products had some beneficial bacteria, but contained fewer species of organisms than the label claimed. More than 30% of all supplements were contaminated with other microorganisms and 50% of the non-refrigerated products were completely dead. Dead probiotics have no impact on improving intestinal function or restoring the balance of normal intestinal flora.
The deficiencies found in these probiotic supplements may be due to poor manufacturing processes, poor quality control, or other environmental factors that cause the bacteria to deteriorate. While some probiotics are stable at room temperature, most require refrigeration to maintain live cultures. The findings in the new study suggest that many probiotic supplements will provide no benefit due to lack of viable organisms and may cause infection if contaminated with organisms that cause disease. However, no reports have been published linking a probiotic supplement to an intestinal infection. It is unclear at this point whether there are any adverse effects from the bacterial contaminants found in probiotic supplements.
Despite the quality-control concerns with probiotic supplements, many of the available products appear to be safe and effective in clinical practice. The one product that contained exactly what was listed on the label was Lactobacillus GG, a specific strain of beneficial bacteria. Studies have shown that Lactobacillus GG is useful in treating acute and chronic intestinal infections, preventing eczema in children, and stimulating the immune system.
Choosing a probiotic supplement can be difficult since it is not possible to know whether the product contains live cultures at the time of purchase. Selecting a refrigerated product may be more beneficial, since they were found to be more likely to contain live bacteria. If taking a particular product does not appear to be effective, some physicians recommend trying another product before discontinuing the treatment altogether. Probiotics may also be found in some cultured dairy products, such as some yogurt products and some types of milk. However, people with a dairy allergy or lactose intolerance may prefer taking a supplement. Some physicians recommend taking a supplement that contains 3 to 5 billion live organisms per day in between meals.
Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of The Natural Pharmacist: Lowering Cholesterol (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice at New England Family Health Associates located in Southport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.
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