Obesity and female gender increase breath ethanol concentration: Potential implications for the pathogenesis of nonalcoholic steatohepatitis

OBJECTIVES: Similarities between histological features of alcoholic hepatitis and obesity-related liver disease suggest a common pathogenic mechanism. Because intestinal bacteria can produce ethanol, it is conceivable that intestinally derived alcohol may contribute to fatty liver disease. An indirect way of measuring endogenous ethanol is to measure the breath ethanol concentration. In a previous study in ob/ob mice, breath ethanol decreased with a course of non-absorbable antibiotics, suggesting that the ethanol is derived from intestinal bacterial flora. The aims of this study were 1) to determine whether alcohol can be detected in the breath of human subjects, and 2) to assess whether there is any correlation between ethanol and obesity in patients with nonalcoholic steatohepatits (NASH) and control subjects without known liver disease. METHODS: Breath ethanol concentration was determined in 21 patients with biopsy-proven NASH and in 10 control subjects by gas chromatography. An abnormal breath ethanol level was defined as two standard deviations above the mean value of the breath ethanol of lean controls. RESULTS: Minute quantities of ethanol were detected in the breath of human subjects who had not consumed alcohol in the recent past. Patients who were obese were more likely to have higher breath ethanol concentrations. Women also had higher breath alcohol than men. However, there was no difference between patients with NASH and controls. Severity of liver disease, as evidenced by cirrhosis, did not influence the breath ethanol concentration. CONCLUSIONS: Higher breath ethanol concentrations are observed in obese subjects than in leaner ones. It is possible that intestinally derived ethanol may contribute to the pathogenesis of NASH.