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New Zealand gastroenterologists and surgeons are advising people who have had stomach stapling surgery to go easy on alcohol drinking.
In a new study, US researchers say people who have had the obesity surgery got drunk after just one glass of red wine.
"A lot of people think they can have one glass of wine and be OK," said Dr John Morton, assistant professor of surgery at Stanford University Medical Centre, who is the study's lead author.
"The concern here is they really can't."
Dr Morton has performed more than 1000 gastric bypass, or stomach stapling, surgeries.
He said he routinely warned his patients about drinking alcohol.
"I didn't find a whole lot in the literature, so that prompted the study," he said.
Dr John Wyeth, gastroenterologist at Wellington's Southern Cross Hospital, told NZPA today that doctors in New Zealand routinely advised patients who have had obesity surgery operations about post-operation ill-effects of alcohol intake.
"Whenever you talk about alcohol, it gets quite complex because a lot of the effects of alcohol are really due to psychological factors, rate of absorption, previous exposure to alcohol, and tolerance levels."
So a predicted response to alcohol was almost impossible, Dr Wyeth said.
"However, the absorption of alcohol does involve the stomach and intestine, then being absorbed into the blood and going to the liver. What we are doing is interfering with part of the pathway. We are reducing some of the gastric volume, thus speeding up the level of alcohol absorption."
Dr Wyeth said the alcohol was going to be put through the small intestine faster, depending on the type of gastric operation.
"So there was a lot of potential for the normal breakdown of absorption metabolism of alcohol to be abnormal."
Moderation was the rule, Dr Wyeth said.
"We always advise patients who have the operation to go easy on alcohol. Alcohol has calories in it and the reason they have had the operation is to try and reduce the calorie intake."
Patients are advised to be prudent because "the effects of alcohol after the operation was going be different", he said.
The US research team gave 36 men and women - 19 who had obesity surgery and 17 who did not - five ounces of red wine each to drink in 15 minutes.
Using a breathalyser, their alcohol levels were measured every five minutes until it returned to zero.
More than 70 percent of the surgery patients hit a blood-alcohol level of 0.08 percent, which qualifies as legally intoxicated in California, and two reached levels above .15, Morton said.
By contrast, most of the control group had levels below 0.05 percent, the study reported.
Researchers also found that obesity patients took longer to sober up.
After matching the control group with the patient group for age, gender and weight, they found the patients took 108 minutes on average to return to a zero blood-alcohol level versus 72 minutes for the control group.
Dr Morton said the obesity surgery patients did not produce as much of an enzyme that breaks down alcohol because their stomachs were smaller.
Also, the alcohol passed to their small intestine faster, speeding up absorption, he said.
The findings, which were presented recently at a meeting of bariatric surgeons, highlight an important warning for obesity patients: "Never have more than a couple of glasses in a single sitting, and don't drive afterward," Dr Morton said.
Meg Semrau, a nurse co-ordinator of Stanford's bariatric programme who had gastric bypass surgery herself more than three years ago, said she noticed her tolerance for alcohol was lower after surgery.
"I literally feel it within a couple of sips now," she said. "Flushing in the face, a kind of disequilibrium."
While some experts took issue with the study's size and methodology, they said it basically confirmed what they had suspected for some time: People who have gastric bypass surgery are more sensitive to alcohol.
Dr Madelyn Fernstrom, director of the weight management centre at the University of Pittsburgh Medical Centre, said Dr Morton's results support alcohol warnings normally given to gastric bypass patients.
However, she called drinking five ounces of wine in 15 minutes an "artificial" test. No one - let alone bariatric surgery patients - would be advised to drink that amount of alcohol so quickly, she said.
In fact, Dr Fernstrom said patients were discouraged from drinking alcohol because it is a "waste of calories".
"Alcohol is not part of a healthy diet for gastric bypass surgery patients," she said.
"If this is a pleasant part of life to certain people on special occasions, it must be monitored and discussed with their surgeon."
- NZPA
