Moderate alcohol consumption is associated with small intestinal bacterial overgrowth, study finds

The retrospective review, "Moderate Alcohol Consumption is Associated with Small Intestinal Bacterial Overgrowth," 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 -- and neither smoking nor use of heartburn drugs called PPIs was associated with an increased risk of SIBO.

Small intestinal bacterial overgrowth is a condition where abnormally large numbers of bacteria grow in the small intestine. Normally the small intestine contains a relatively low number of bacteria in contrast to the large intestine, which should contain a larger number of bacteria. In patients with SIBO, the abnormally large numbers of bacteria in the small intestine use for their growth many of the nutrients that would otherwise be absorbed.

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.

While previous studies have focused on alcoholics, who were found to have high rates of SIBO, this 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. Moderate alcohol consumption means no more than 1 drink per day for women and 2 drinks per day for men, with twelve ounces of regular beer, 5 ounces of wine, or 1-1⁄2 ounces of 80-proof distilled spirits counting as one drink, according to the USDA dietary guidelines.

An overwhelming majority (95 percent) of the 198 patients in the study drank a moderate amount of alcohol, sometimes less than 1 drink per day, said Dr. Gabbard, who also indicated that only four of the patients drank more alcohol -- a finding he noted indicates that consumption of even the slightest amount of alcohol could have an impact on gut health.

"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," he said. "While typical treatment for SIBO has been antibiotics, probiotics or a combination of the two, the question now becomes what is the exact association between moderate alcohol consumption and SIBO and whether alcohol cessation can be used as a treatment for this potentially harmful condition."