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Yogurt Drink Prevents Antibiotic-Induced Diarrhea

Posted by medconsumers on July 8, 2007

A yogurt drink sold in many supermarkets has been shown to reduce the risk of severe diarrhea that can occur after taking antibiotics. The study, published last month in the British Medical Journal Online First, was conducted at several hospitals, a setting where people are most likely to be exposed to drug-resistant strains of bacteria.

Of particular concern in most industrialized countries is the emergence of Clostridium difficile, an increasingly common, sometimes fatal, complication of antibiotic treatment, which occurs in about 5-25% of all hospitalized patients, usually two or three weeks after finishing antibiotic treatment.

Eating yogurt is now a standard way for people to protect themselves while on antibiotics. And to serve this expanding market, more and more yogurt products now feature the word probiotics on the label, claiming that they contain live cultures. Probiotics are defined as “live micro-organisms which when administered in adequate amounts confer a health benefit on the host.” Most probiotic products contain bacteria that help to balance the hundreds of different species of bacteria found in the human body.

Probiotics are gaining some research attention because of the overuse of antibiotics and the resulting increase in drug resistance. Probiotic-containing foods and capsules are consumed to overcome the tendency of antibiotics to kill the normal as well as the harmful bacteria. The problem with products claiming to contain probiotics or “live active cultures” is that they are unregulated, so it’s impossible to know whether they actually contain adequate amounts of live bacteria and the right strains of live bacteria.

British Hospital Study

The probiotic drink used in the newly published British hospital study was Actimel, sold as DanActive in the U.S. This study was partly funded by Danone, a French company that makes both products, which contain Lactobacillus casei, L bulgaricus and Streptococcus thermophilus. All three strains had already been evaluated for the prevention or treatment of diarrhea associated with antibiotic use and found to be safe, according to the British researchers led by Mary Hickson, Imperial College, London, England.

The researchers recruited patients from three London hospitals. All were asked to participate within 48 hours of taking their first dose of antibiotics prescribed for a variety of infections unrelated to any gastrointestinal ailments. The 113 patients (mean age, 74 years) who decided to participate were randomly assigned to drink either four ounces of Actimel or a placebo drink (milkshake).

All agreed beforehand to take the assigned drink twice a day during the course of antibiotics and for one week after completing the regimen. Neither the patients nor the hospital staff knew who was in the probiotics group and who was in the placebo (milkshake) group. When participants developed diarrhea, stool samples were analyzed for the potentially fatal Clostridium difficile toxin.

The hospital patients in the probiotics group fared much better than those in the placebo group. Hickson and colleagues concluded, “Consumption of a probiotic drink containing L casei, L bulgaricus and S thermophilus can reduce the incidence of antibiotic-associated diarrhea and C difficile-associated diarrhea. This has the potential to decrease morbidity, heath care costs, and mortality if used routinely in patients over age 50.”

Here are the results of the study: 12% of the hospital patients in the probiotic group developed diarrhea associated with antibiotic use, compared with 34% of the patients in the placebo group. No one in the probiotics group developed C difficile, but 9% of the patients in the placebo group developed this serious complication.

Cost Effective, Too

Hickson and colleagues provided this estimate of the cost savings in U.S. dollars. The average cost of the probiotics regimen in this study was $20 per patient. The cost of preventing one case of C difficile-associated diarrhea with probiotics was estimated to be $120, excluding dispensing and nursing costs. This is due to that fact that six patients were treated with probiotics for each case of C difficile prevented.

The $120 was then compared with the $3,669 it would cost in the U.S. to provide the standard medical treatment for one person with C difficile. The high cost is mainly due to the increased length of hospital stay required for people with C difficile and the use of a costly intravenous antibiotic called vancomycin, according to Hickson and colleagues.

Vaginal Infections

Something important to women was not addressed in the British study. Many eat yogurt while on antibiotics in order to avert another nasty side effect—vaginal infections. Will the yogurt drink used in this study have any preventive benefit for this infection? The answer is no, according to a leading probiotics expert not associated with the British study: Gregor Reid, PhD, Canadian Research and Development Centre for Probiotics in London, Ontario. “The product [Actimel/DanActive] is designed for intestinal benefits and not for the type of bacteria strains needed to promotevaginal health.”

There is, however, another product proven to reduce the risk of vaginal infections, called Fem-Dophilus (, said Dr. Reid, who owns patents to the strains present in these capsules. As for the probiotic claims on numerous products sold in supermarkets and pharmacies: “It’s only a probiotic if the product formulation has been clinically tested. Many of them have not. At least, if they have the strains of probiotic in a suitable viable count as found in studies with other formulations, it is promising, but the real test is a human study with the formulation.”

Maryann Napoli, Center for Medical Consumers ©
July 2007

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