Moderate alcohol consumption - just one drink per day for women or two for men - could lead to small intestinal bacterial overgrowth (SIBO) and subsequently cause gastrointestinal symptoms like bloating, gas, abdominal pain, constipation and diarrhea, a new study has suggested. The study looked at the charts of 198 patients who underwent lactulose hydrogen breath testing (LHBT) to determine the presence of SIBO, and found that any current alcohol consumption was significantly associated with the presence of SIBO. The increased risk of SIBO was neither associated with smoking nor use of heartburn drugs called PPIs. Small intestinal bacterial overgrowth is a condition where abnormally large numbers of bacteria grow in the small intestine. As a result, a person with small bowel bacterial overgrowth may not absorb enough nutrients and become malnourished. In addition, the breakdown of nutrients by the bacteria in the small intestines can produce gas as well as lead to a change in bowel habits. The study by Scott Gabbard, MD and colleagues at the Dartmouth-Hitchcock Medical Center and the Mayo Clinic, is one of the first to look at the relationship between moderate alcohol consumption and SIBO. The findings have been presented at the American College of Gastroenterology's (ACG) 76th Annual Scientific meeting in Washington, DC.