Dr. Scott Gabbard and colleagues at the Dartmouth-Hitchcock Medical Center and the Mayo Clinic said just one drink per day for women -- two for men -- could lead to small intestinal bacterial overgrowth and subsequently cause gastrointestinal symptoms such as bloating, gas, abdominal pain, constipation and diarrhea.
The researchers examined the charts of 198 patients who underwent lactulose hydrogen breath testing to determine the presence of small intestinal bacterial overgrowth.
Gabbard and colleagues found any current alcohol consumption was significantly associated with the presence of small intestinal bacterial overgrowth -- and neither smoking nor use of heartburn drugs were associated with an increased risk of small intestinal bacterial overgrowth.
Moderate alcohol consumption means no more than one drink per day for women and two drinks per day for men, with 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled spirits counting as one drink, U.S. Department of Agriculture dietary guidelines.
"These findings are significant because we now know that any bit of alcohol consumption -- not just the amount consumed by alcoholics -- is a strong predictor of a positive lactulose hydrogen breath testing and small intestinal bacterial overgrowth," Gabbard said in a statement.
The findings were presented at the American College of Gastroenterology's 76th annual scientific meeting in Washington.