Patients who have had a gastric bypass operation take longer to process alcohol, potentially leading some of them to overindulge when drinking, according to the results of a new study in the February issue of the Journal of the American College of Surgeons.

Previous studies have shown that gastric bypass patients often find it difficult adjusting to physical and psychological changes after the procedure. An increased risk of depression, alcoholism, and other substance abuse issues for this patient population led researchers to take a more in-depth look at how these patients metabolize alcohol after the procedure.

The results of this unique demonstration of alcohol metabolism changes in gastric bypass patients showed that patients who underwent a Roux-en-Y gastric bypass (RYGB) operation had considerably higher breath alcohol content (BAC) and took significantly more time to return to a sober state after drinking, compared with BAC levels tested prior to having their procedure.

“Severe obesity continues to be a public health crisis in the U.S., and bariatric surgery offers a very effective treatment,” said senior author John M. Morton, MD, MPH, FACS, associate professor of surgery at Stanford (CA) University. “Despite its benefits, we want to raise the potential concern for RYGB patients who continue to drink after their operation because they may tend to overuse alcohol, which can, in turn, lead to weight regain, nutritional deficiencies, and/or alcohol dependence.”

During the study, alcohol metabolism tests were performed on 19 morbidly obese patients before their RYGB operation and then measured again at three and six months post-operation. Patients also reported symptoms experienced when drinking and answered a questionnaire about their drinking habits.

The results showed peak BAC percentage of patients after drinking five ounces of red wine was significantly higher post-operation. BAC was 0.024 percent at pre-operation and 0.059 percent (p = 0.0003) at three months. Tested again at six months post-operation, the patients’ BAC was 0.088 percent (p = 0.0008) which is more than the legal driving limit of .08 percent. Additionally, it took 49 minutes for patients to reach a zero BAC prior to their operation compared with 61 minutes at three months and 88 minutes at six months post-operation.

In other studies, researchers have found that a few gastric bypass patients undergo an addiction transfer where they trade one vice, such as overeating, for another, like over consumption of alcohol or drug use. Additionally, patients who display binge eating behavior prior to their operation have the highest likelihood of postoperative alcoholism.

“RYGB patients need to understand that their body will respond to alcohol differently after their operation and they need to exercise caution if they choose to drink alcohol,” said Dr. Morton. “Our recommendation to all of our RYGB patients is never drink and drive and to limit consumption of alcohol to one standard drink (one 12-oz beer, 5-oz wine, or 2-oz liquor) for every two hours. The key to safeguarding bariatric surgery benefits is to provide appropriate patient education.”