A Texas man who was struggling with episodes of sudden and unexplained drunkenness was found to have alcohol-producing microbes in his gut, which were busily making beer.

According to NPR’s science blog The Salt, a 61-year-old man reported to a Texas hospital emergency room complaining of dizziness and disorientation. His blood alcohol level checked out at nearly five times the legal limit for motor vehicle operation. However, the man insisted that he hadn’t drunk any alcohol at all that day.

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“He would get drunk out of the blue — on a Sunday morning after being at church, or really, just anytime,” said Barabara Cordell, dean of nursing at Carthage, TX’s Panola College. “His wife was so dismayed about it that she even bought a Breathalyzer.”

Health care workers were baffled. Initially they assumed that the man was being dishonest and was drinking on the sly. Cordell and gastroenterologist Dr. Justin McCarthy, however, thought there might be another cause.

They checked the patient in to a hospital room for 24 hours and made absolutely sure that he had not smuggled in any alcohol. They fed him foods rich in carbohydrates and monitored his blood alcohol levels. Sure enough, his blood alcohol content began to spike on its own.

Cordell and McCarthy realized that the man, who was an avid home brewer, had an abundance of brewer’s yeast in his gut, making his intestines act as their own small brewery.

The yeast that colonized the patient’s alimentary tract is called Saccharomyces cerevisiae, and is popular with brewers because of its ability to digest sugars and carbohydrates and convert them into alcohol. The resulting disorder is called “auto-brewery syndrome.” Cordell and McCarthy published their findings in the International Journal of Clinical Medicine.

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Duke University microbiologist Dr. Joseph Heitman told NPR, “Researchers have shown unequivocally that Saccharomyces can grow in the intestinal tract. But it’s still unclear whether it’s associated with any disease.”

Other reports of similar incidents stretch back all the way into the 1970s. All of the patients affected by auto-brewery syndrome had taken antibiotics or were immune-suppressed, meaning that normal enteric organisms were killed off or in short supply, leaving a niche for yeast and other organisms like fungi to flourish.

Heitman told NPR that he’d never heard of auto-brewery syndrome before this case, but that “(i)t sounds interesting.”

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He said, “The problem with a case report is that it’s just one person. It’s not a controlled clinical study.”

[image of drunk man holding beer via Shutterstock.com]