Action of pure ethanol and some alcoholic beverages on the gastric mucosa in healthy humans: A descriptive endoscopic study

Background and Stony Aims: The action of ethanol and alcoholic beverages on the gastric mucosa in healthy humans is largely unknown. This study was designed to compare the effects of beer, white wine, whisky, and the comparable pure ethanol solutions on the gastric and duodenal mucosa in a controlled, randomized, double-blind endoscopic investigation. Materials and Methods: In 47 healthy human volunteers, 100 ml of beer, or white wine, or whisky, or a comparable pure ethanol solution (4%, 10 %, 40 % vol/vol), or isotonic saline as a control, were sprayed on the antral mucosa. The endoscopic appearance of the gastric and duodenal mucosa was assessed before, immediately after, and 30, 60, 240 minutes and 24 hours after instillation. The lesions were scored using an endoscopic grading system (0-5; 0=normal mucosa and 5=ten or more hemorrhagic lesions). Results: Pure ethanol damaged the gastric mucosa in a dose-dependent fashion. The lesions occurred within 30 minutes, and reached a maximum after 60 minutes (antral score for 4%=1.3; 10%=1.8; 40% 3.8; control=1.5). Beer, wine and whisky also induced gastric mucosal injury, but to a lesser extent than the comparable ethanol solutions. The 24-hour integrated endoscopic scores for beer and wine were significantly lower (P<0.05) than the corresponding ethanol content. In the case of pure ethanol>10% and whisky, the lesions were still present 24 hours later (antral score for 10 % = 1.5; 40 % = 2.0; whisky = 2.3; control = 0). No lesions were observed in the duodenum. None of the volunteers reported any abdominal pain during the whole investigation. Conclusions: Intragastric application of 4%, 10%, and 40% vol/vol pure ethanol induces gastric, but not duodenal, mucosal lesions in a dose-dependent fashion. Beer, white wine, and whisky induce gastric mucosal lesions to a lesser degree than the corresponding ethanol content. Lesions induced by higher ethanol concentrations (>10%) and whisky take more than 24 hours to heal. The lesser damage caused by alcoholic beverages may be due to the protective action of unknown nonalcoholic ingredients.