Gastric Bypass Surgery Linked to Alcohol Dependence

Summary
Obesity is a major public health problem. In the United States, the percentage of obese people has increased from 15 percent of the population in 1980 to 33.3 percent of men and 35.3 percent of women in 2006. Gastric bypass surgery has been found to be useful for weight loss in extremely obese patients; but the change in metabolism after surgery is a cause for concern. This study found that alcohol metabolism is changed — peak alcohol levels become higher and the time it takes to become sober is prolonged — after gastric bypass surgery in patients. The symptoms of intoxication also change after surgery. Patients who have undergone gastric bypass surgery for obesity need to be careful about alcohol consumption.

Introduction
Surgical bypass of the stomach (bariatric surgery) is an effective therapy for severe obesity. This surgery is known to produce a 25 to 30 percent reduction in total weight, and also reduce mortality by 37 percent. However, patients who have undergone bariatric surgery are known to develop psychological problems like major depression and alcoholism. Alcohol abuse in bariatric surgery patients can lead to deaths from automobile accidents and alcohol poisoning. It can also cause vitamin B-1 deficiency and weight gain due to increased caloric intake. There is evidence that alcohol metabolism is altered in patients who have had bariatric surgery. This study compared alcohol metabolism in such patients before and after their surgery.

Methodology
* Included in this study were 19 morbidly obese patients who were undergoing gastric bypass surgery. Weight and body mass index (BMI) were measured before surgery and at intervals of two weeks, six weeks, three months and six months after the surgery.
* Before the surgery, and at three months and six months after the surgery, patients were given 5 oz. of red wine to drink in less than one minute. Blood alcohol content was measured by a breathalyzer.
* Patients were given a questionnaire about their drinking habits, alcohol preferences, and symptoms they experienced while intoxicated.

Results
*  The mean BMI was 49.1 before surgery. It decreased to 40.4 at three months and 36.6 at six months after the surgery.
* The peak blood alcohol content was 0.024 percent before surgery. It increased to 0.059 percent at three months and 0.088 percent at six months after surgery.
* The time it took to become sober was 49 minutes before surgery. It increased to 61 minutes at three months and 88 minutes at six months after the surgery.
* Before surgery 74 percent of patients reported drinking alcohol. After surgery, this percentage dropped to 44 percent. The amount of alcohol and the number of days in a week it was consumed was also reduced after surgery.

Next steps/Shortcomings
The study used indirectly inferred blood alcohol levels from the actual levels indicated by a breathalyzer analysis. The validation of the breath alcohol measuring device has not been performed in extremely obese patients previously. Furthermore, ketones are metabolic products formed during weight loss. The levels of ketones might have interfered with the breathalyzer readings.

Conclusion
This study shows that patients, after undergoing gastric bypass surgery for weight reduction, should be careful about alcohol consumption. After surgery, drinking even small amounts of alcohol can lead to breath-alcohol levels greater than the legal driving limit of 0.08 in the U.S. The symptoms of intoxication also differ after surgery. Gastric bypass patients may not recognize these symptoms and could overindulge. Many patients have psychological difficulty in adjusting to weight loss induced by surgery. Alcohol consumption in such patients can produce alcohol dependence, which could lead to weight regain. In conclusion, obese patients undergoing gastric bypass for weight management should, if possible, avoid or limit their intake of alcohol after the surgery.

For More Information:
Impaired Alcohol Metabolism after Gastric Bypass Surgery: A Case-Crossover Trial
Publication Journal: Journal of American College of Surgeons, 2010
By Gavitt A. Woodard; John Downey, MD; Stanford University School of Medicine, Stanford, California

*FYI Living Lab Reports Are Summaries of the Original Research.