Auto-Brewery Syndrome: Fungi in Woman’s Gut Brew Their Own Alcohol, Make Her Drunk Despite Not Drinking

A type of fungi called brewer's yeast can overgrow in the human gut and ferment sugar, making alcohol in a person's body.

A Rare Cause of Drunkenness

A 50-year-old woman kept ending up in hospital due to similar symptoms that made her seem drunk, such as slurred speech, excessive sleepiness, and the scent of alcohol on her breath. Over the course of two years, she had been referred to emergency departments seven times.

Among the symptoms, her sleepiness was troubling as she would suddenly fall asleep while preparing meals or getting ready for work. This would suppress her appetite and keep her out of work for weeks.

During each visit to the emergency room, the woman is diagnosed with alcohol intoxication. However, the patient had stopped drinking altogether due to her religious beliefs. Her family also confirmed that she had not ingested a drop of liquor.

She was finally referred to a gastroenterology clinic, and the doctors eventually discovered that the woman's medical history held a clue as to what was causing her drunkenness. Her case was published on June 3 in the paper "Auto-brewery syndrome in a 50-year-old woman."

Before having the drunken episodes, the woman had a five-year history of recurrent urinary tract infections (UTIs), a condition that comes back repeatedly and is very difficult to avoid. She was given frequent courses of antibiotics to treat her infections.

The doctors suspected that the heavy doses of antibiotics cleared her UTIs, but they also wiped out the helpful bacteria in the woman's gut. This cleared the way for various fungi to take over in the gut, with some of them having the ability to ferment carbohydrates.

This means that microbes in her gut were brewing their own alcohol and making her drunk. Doctors eventually diagnosed the woman with a rare medical condition called auto-brewery syndrome.

The woman was placed on a low-carb diet in order to deprive the fungi of a source of sugar to ferment. The symptoms went away for several months, so she increased her carbohydrate intake, but the drunkenness symptoms returned. Antifungal drugs and a low-carb diet were recommended again to eliminate the symptoms.

The woman was also given probiotics to restore the helpful bacteria in her gut. Meanwhile, her primary care doctor gave her narrow-spectrum antibiotics for UTIs.

Broad-spectrum antibiotics likely kill many bacteria at once, affecting the gut microbiome. On the other hand, narrow-spectrum antibiotics are much more targeted and can be customized to the bacteria that likely cause the infection.

The patient finally went months with no relapses, so the doctors tested if the consumption of carbohydrates would increase the levels of alcohol in her blood. Finding that it did not, they advised the woman to slowly increase her carbohydrate intake while being monitored by the clinical team.

What Is Auto-Brewery Syndrome?

Auto-brewery syndrome is a condition that arises when fungi grow in high enough concentrations and access carbohydrates in a person's diet. These fungi may include Saccharomyces cerevisiae or brewer's yeast and Candida albicans.

Some strains of bacteria have also been linked to auto-brewery syndrome. People with high blood sugar and less ability to break down alcohol are believed to be more prone to the disorder.

Auto-brewery syndrome is very rare, and it can be difficult to get a diagnosis for this medical condition. Since its discovery in the late 1940s, fewer than 100 cases have been reported.

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