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Mark DiOrio, Deseret News archives
Salt Lake County Sheriff Sgt. Paul Brenneman checks the first in a line of vehicles at a DUI checkpoint. Salt Lake County Sheriff officials and local police authorities set up a checkpoint at the mouth of Cottonwood Canyon in Cottonwood Heights, UT, May 26, 2006, to look for underage drivers in possession of alcohol and intoxicated drivers. A rare condition in which yeast and sugar in the gut combine to make a person drunk may be of special concern to Utahns after the state's new DUI law takes effect.

SALT LAKE CITY — A rare condition in which yeast and sugar combine in the gut to make a person drunk, without drinking, may be of special concern to Utahns after the state's new DUI law takes effect at the end of 2018.

Auto-brewery syndrome, also known as gut fermentation syndrome, can cause the same bodily responses as drinking alcohol, and at least one person has had drunken driving charges dropped after convincing a judge she has the condition.

With Utah preparing to enact the nation's lowest blood-alcohol content limit for motorists, one which even the founder of Mothers Against Drunk Driving decried, does this mean that Utahns will soon be pulled over for intoxication caused by something they ate?

The Utah County Sheriff's Department perform a DUI checkpoint on Highway 6 near Elberta on Friday April 6, 2012. A rare condition in which yeast and sugar in the gut combine to make a person drunk may be of special concern to Utahns after the state's new DUI law takes effect. | Utah County Sheriff's Office

It's possible, but not likely.

The condition is exceedingly rare, and few cases have been documented. Usually it occurs in combination with other gastric problems that required surgery. But if you or someone you know suffer from unexplained nausea, headaches, dizziness or brain fog, you might want to learn more about auto-brewery syndrome and its effects before Utah's new DUI law kicks in.

The brewery within

While sugar is increasingly seen as a nutritional villain, it's not as dangerous as vodka for people about to get behind a steering wheel — unless you have an overgrowth of yeast in your gut.

Yeast are microorganisms, fungi that are energized when fed sugar and starch, becoming a “bubbly, oozing mess of life,” according to Scientific American magazine. When yeast and sugars interact, they create ethyl alcohol and carbon dioxide.

When this happens in a brewery, you get beer. When this happens in your gut, you have auto-brewery syndrome.

It's not exactly the same process, and the type of yeast in your body is likely not the same kind that's in your pantry. There are about 1,500 species of yeast in the world. Brewer’s yeast, the kind you buy in stores in little packets, is from the Saccharomycetaceae family; yeast that colonizes a body is typically Candida albicans, a parasite, according to the truth-sniffing website The Straight Dope.

Officers set up a DUI checkpoint in Lehi in 2014. A rare condition in which yeast and sugar in the gut combine to make a person drunk may be of special concern to Utahns after the state's new DUI law takes effect. | Alex Cabrero, KSL

The effects, however, are similar.

“When candida metabolizes sugars it produces byproducts and chemical derivatives of alcohol. When those get into your circulatory system, it can give you the feeling of being hung over or drunk," Kiran Krishnan, a Florida microbiologist, said in Reader’s Digest magazine.

And for certain people, the result of these gut interactions is not just a feeling, but a measurable change in blood-alcohol content, Krishnan told Reader's Digest writer Alyssa Jung.

"It’s just like what happens when you drink, except it’s chronic. Drinking causes inflammation in the body and puts stress on the liver, and so does this. It’s basically like these microbes in your body are drinking and having a party and you’re paying the price for it," he said.

A British man named Matthew Hogg who has auto-brewery syndrome told Vice that in his teens he noticed that was experiencing what felt like an alcohol hangover after eating meals high in carbohydrates.

"I'd get pounding headaches, severe nausea, occasional vomiting, dehydration, dry mouth, cold sweats and shaky hands. It was as if I'd been out the previous night and drunk the bar dry, but I hadn't consumed any alcohol," Hogg said.

After his diagnosis, he began eating what he calls "a Stone Age diet," mostly meat, vegetables, nuts and seeds. He still occasionally suffers from fatigue and brain fog, but says that the dietary changes prevent the worst of the condition, "symptoms of an acute, severe hangover."

Another man, whose case was described in the International Journal of Clinical Medicine in 2013, was so afflicted by his internal brewery that his wife bought a Breathalyzer so she could monitor his condition. Doctors in Texas treated the 61-year-old man with antifungal medicine and a low-carb diet, and he improved.

"It would behoove health care providers to listen more carefully to the intoxicated patient who denies ingesting alcohol," the authors wrote.

Officers set up a DUI checkpoint in Lehi in 2014. A rare condition in which yeast and sugar in the gut combine to make a person drunk may be of special concern to Utahns after the state's new DUI law takes effect. | Alex Cabrero, KSL

Auto-brewery syndrome in the courtroom

There are skeptics, among them Barry K. Logan, former chief of the Washington State Toxicology Lab, who has co-authored studies that challenged the claims of inadvertent intoxication. In one published in 2000, the authors acknowledged "seemingly reliable" reports of auto-brewery syndrome in Japan, but noted that most people suffering symptoms had been diagnosed with chronic yeast infections and other gastric maladies, some of which had required abdominal surgery.

Fungal infections are increasing worldwide, especially in people who are critically ill and have suppressed immune systems, and some of these patients experience ethanol production in their guts, "although it is hardly likely that such individuals would be driving on the highway," the study said.

"In the extensive literature we reviewed, we could find no tangible evidence to support the contention that significant concentrations of ethanol are produced in the gut which compromise the use of blood- or breath-alcohol analysis for forensic purposes," the authors concluded.

But at least one judge has accepted evidence to the contrary.

The Utah County Sheriff's Department perform a DUI checkpoint on Highway 6 near Elberta on Friday April 6, 2012. A rare condition in which yeast and sugar in the gut combine to make a person drunk may be of special concern to Utahns after the state's new DUI law takes effect. | Utah County Sheriff's Office

In January 2015, a New York judge dismissed DUI charges against a woman who tested four times the legal limit for alcohol, according to CNN. The woman had actually been drinking the afternoon she was charged, but the spacing of the drinks should have not made her intoxicated, her lawyer said.

When the woman was taken to the hospital after passers-by noticed she was woozy while trying to change a tire on the side of the road, she registered 0.40 on a blood-alcohol test. The standard for drunken driving in New York is .08, like the rest of the country.

In Utah, however, the bar drops to .05 on Dec. 30, 2018.

In Utah and elsewhere, some of the people with auto-brewery syndrome could be charged with DUI if they were driving and police pulled them over, even now.

In the case of the Texas man detailed in the International Journal of Clinical Medicine, blood testing done at hospitals at separate times showed an alcohol concentration of 0.12 and 0.37 percent on days that he had not consumed any alcohol.

The Utah County Sheriff's Department perform a DUI checkpoint on Highway 6 near Elberta on Friday April 6, 2012. A rare condition in which yeast and sugar in the gut combine to make a person drunk may be of special concern to Utahns after the state's new DUI law takes effect.| Utah County Sheriff's Office

In that case, just before the man began exhibiting unexplained inebriation, he had completed a course of antibiotics, which is one theory about how the condition develops. Antibiotics kill both harmful and beneficial microbes, and in a gut deficient of microbia, it's easy for candida to take over and flourish.

So, if you've recently taken antibiotics and suddenly start feeling woozy after having a carbohydrate-rich meal — and you don't drink — you might want to ask your doctor for a blood-alcohol test. Just get someone else to drive you to the doctor's office.

But it's more likely you just have "grain brain," a mental and physical lethargy that neurologist and author Dr. David Perlmutter says is epidemic in people who eat too many carbs.

Regardless, don't drink and drive in Utah. The standard that takes effect at the end of 2018 has been widely criticized, but was recommended by the National Transportation Safety Board, which says the change will reduce fatal car accidents.

Critics say this means a 100-pound woman can only have one drink before becoming too impaired to drive.

The average American woman, however, weights 168.5 pounds, according to the Centers for Disease Control and Prevention, and the average American man weighs 195.7.

According to a blood-alcohol chart prepared by the Texas Alcohol Beverage Commission, that average woman would have a blood-alcohol level of .03 after one drink; the average man, .02; which means that both could legally drive in Utah even after the law takes effect.