If you have had gastric bypass surgery, keep an eye out for any changes in how and when you drink.
The procedure can increase the risk of alcohol use disorder.
And that can happen even years after surgery, according to new published this spring in an online issue of the journal of the American Society for Metabolic and Bariatric Surgery (ASMBS).
One in 5 people who’ve had bypass surgery met the study definition for the disorder at some point within five years of their surgery, even though they hadn’t had a problem in the year before their procedure.
What researchers discovered
The research team was led by Wendy King, associate professor of epidemiology at the University of Pittsburgh.
They assessed nearly 1,500 people who’d had bypass surgery, one, two, three, four, five, and seven years after the procedure.
By the second year, King told Healthline, “We found an increase in drinking frequency and problems. There were people affected for the first time each year.”
The team used a standard 10-item test to ask people about their drinking and its consequences in the previous year.
If you got a high score or said that you had experienced any of the classic symptoms of the condition — like needing a drink in the morning to get going, or injuring someone while inebriated — you met the definition of alcohol use disorder.
Not only were people who’d had bypass surgery more likely to develop drinking problems, but their drinking became more frequent over the years.
Some 16 percent of people said they were drinking at least twice a week by the last year of the research assessment, compared with around 6 percent pre-surgery.
Drinking twice a week may not sound serious, but doctors advise weight loss patients to stay away from liquid calories. After weight loss surgery, patients take in dramatically fewer calories. The alcohol may affect weight and cause other problems, King said.
Given the results, people who’ve had bypass surgery might want to stay away from alcohol altogether, King suggested.
“Some had symptoms even if they drank less than twice a week. Maybe you don’t drink for a month, but when you do one night you can’t stop,” King said.
How much weight participants lost, or whether they were binge eaters before surgery didn’t affect the risk of developing the alcohol-related symptoms, the study found.
The research didn’t cover the “sleeve” procedure, which was new when the participants were first assembled, but now accounts for more than half of all weight loss surgeries, according to the latest ASMBS .
It’s still unclear how the sleeve affects alcohol absorption or consumption.
The study did follow patients who had a “banding” procedure. They turned out to have much fewer issues with alcohol use disorder than people who’d had bypass surgery.
Why alcohol problems develop
Nearly 200,000 people in the United States had surgery to fight obesity in 2015, according to the latest ASMBS figures.
Those numbers are growing as the nation gets heavier. More than 1 in 3 Americans are obese, and more than 1 in 20 fit the definition for “extreme obesity,” according to from the National Institutes of Health (NIH).
The oldest procedure, the gastric bypass, remains the “gold standard,” with the longest record of success, Dr. Manish Parikh, head of bariatric surgery at New York University Medical Center, Bellevue Hospital, told Healthline.
In a bypass, a surgeon first makes a patient’s stomach the size of walnut. The stomach is then attached to the middle of the small intestine, bypassing a section that would normally absorb calories.
Most patients say they become more sensitive to alcohol afterward.
In one , researchers recruited five women who’d had a bypass three or four years earlier and found no reported problems with alcohol.
Each volunteer drank a “screwdriver” — half vodka and half orange juice — on an empty stomach while hooked up to a catheter that collected their blood. They all reached a blood alcohol level above the legal drinking limit within minutes — much faster than the norm.
Alcohol may also take longer to leave the body after a bypass.
In addition, the surgery may change mechanisms in the brain driven by genes, as well as hormones that affect consumption.
Much of this evidence comes from studies with rats, as noted in an published this spring in the online issue of Obesity Reviews.
For example, after scientists performed bypass surgery on rats that don’t like alcohol, the rodents developed a taste for the intoxicant.
In the sleeve, now the most common procedure, the surgeon divides the stomach and staples it vertically, creating a tube or banana-shaped pouch able to hold much less food. This procedure has roughly similar outcomes to a bypass, according to a 2014 by the Cochrane Group. However, it’s newer, so there is less information available about the long-term effects.
One study found that alcohol blood levels rose faster and stayed higher longer after a banding procedure, but another study found no changes. An ASMBS on the topic, written by a team led by Parikh, concluded that more research is needed to settle the question.
There’s no evidence the banding procedure speeds up absorption, but patients tend to regain more weight after a banding than they do with the other options.
Ditch the idea of addiction transfer
If you’re considering the surgery, experts say to banish fears of “addiction transfer.”
A 2006 episode of the Oprah Winfrey show titled , featured patients who’d started drinking after bypass surgery, and declared, “If a patient drops a lot of weight without confronting why they were overweight, they risk becoming addicted to something else. Experts call this swap of one compulsive behavior for another ‘addiction transfer.’”
Actually, the evolving science contradicts that idea.
For instance, people who were depressed before bypass surgery were not more likely to develop alcohol issues. Neither were people who had eating habits that might be deemed addictive.
“We looked at whether loss-of-control eating or binge eating was related to alcohol problems and didn’t find a connection,” King told Healthline.
How much weight you had lost was also unrelated.
“It’s not correct to say obese people are addicted to food, or that they’ll transfer one addiction for another,” Parikh said.
Also, people who quit smoking after bypass surgery were not more likely to develop alcohol issues.
King’s research didn’t look at people who drank frequenty or heavily before a bypass operation. But other research came to the conclusion that they drank less, not more, often after the surgery.
The reason may be that when the physical impact of alcohol intensifies, they adjust their consumption downward.
Yet it’s not obviously a conscious choice. The same phenomenon has been observed in alcohol-loving rats that get a bypass.
“People have different genetic tendencies,” explained Stephanie Sogg, a clinical psychologist specializing in obesity at Massachusetts General Hospital, “and bypass seems to change it.”
At Bellevue, candidates who have a current drinking problem are asked to “get it under control first,” Parikh said, and be abstinent before the surgery.
“We tell patients to abstain from drinking during the first six weeks [after surgery], and then minimize it for one to two years,” he said. “We’d be OK with one or two glasses of wine a week.”
All in all, experts agree that the risks of alcohol abuse shouldn’t be a reason to shy away from bypass or sleeve surgery.
“The only scientifically based conclusion is to be more watchful,” Sogg told Healthline.