Clinical Question: Is yogurt effective in the prevention of antibiotic-associated diarrhea?

Setting: Inpatient (any location) with outpatient follow-up

Study Design: Randomized controlled trial (nonblinded)

Synopsis: Probiotic agents are effective in preventing antibiotic-associated diarrhea. Controversy exists about whether commercially available yogurt products are similarly effective. A total of 202 hospitalized patients receiving oral or intravenous antibiotics were randomized (concealed allocation assignment) to receive vanilla-flavored yogurt (8 oz twice daily for eight days) or usual care without yogurt supplementation.

The authors do not specify the brand or type of yogurt, but note that manufacturer-supplied nutritional data indicated that the product contained active cultures of Lactobacillus acidophilus, Lactobacillus bulgaricus, and Streptococcus thermophilus. The mean age of the study participants was 70 years. All of the patients were followed for a total of eight days. Persons assessing outcomes were not blinded to treatment group assignment. Antibiotic-associated diarrhea was defined as the new onset of more than two less-than-formed bowel movements per day representing a change in previous bowel patterns.

Using intention-to-treat analysis, the authors found that patients receiving yogurt reported less frequent diarrhea (12 versus 24 percent in the usual care group; P = .04; number needed to treat = 12). In addition, patients ingesting yogurt daily reported significantly fewer days with diarrhea (23 versus 60 days). No side effects were reported other than boredom: yogurt-fed patients yearned for fruit-flavored yogurt to break the monotony.

Bottom Line: Vanilla-flavored yogurt containing active bacterial cultures effectively decreases the incidence and duration of antibiotic-associated diarrhea. Patients should be told to consume yogurt that contains active cultures. If they cannot find it, physicians should consider prescribing probiotic agents. (Level of Evidence: 2b)