What Exactly Is Auto-Brewery Syndrome?

What Is Auto-Brewery Syndrome?

Auto-brewery syndrome, or gut fermentation syndrome, is a rare condition that results in the production of ethanol (i.e. alcohol) through endogenous fermentation in the gastrointestinal (GI) system.¹ This means that after a person consumes carbohydrate-rich foods, they can become intoxicated without actually drinking alcohol.¹

Gut fermentation syndrome was first described in Japan in 1952 and was only formally named as such in 1990.^1,2 Since its first documented case, it has been subsequently reported in only a small number of patients.¹ Over the years, this syndrome has been used a defense for DUI cases; though it is unlikely that auto-brewery syndrome would result in sufficient production of ethanol to reach illegal levels of blood alcohol in your system.¹

What Causes It?

Although there have been several reports of auto-brewery syndrome across the globe, there have been few documented details in terms of any demographic, diet, health history or lifestyle factors. What is known through bacterial culturing of affected individuals, though, is the pathogen—Saccharomyces cerevisiae, a type of yeast—which leads to the syndrome.^1,2

Saccharomyces cerevisiae is typically harmless but in situations where it is overgrown in the GI tract (e.g., Crohn’s disease, short bowel syndrome), it can become problematic.¹  Should people experiencing such overgrowth consume carbohydrate-rich foods and drinks, the abundant yeast component of the GI flora could begin to ferment these macronutrients into alcohol.³ As a result, their blood alcohol concentration (BAC) level could begin to moderately rise.

Gut Fermentation Syndrome History

Several early cases were reported in Japan in the 1950s to 1970s,³ with one of the first known cases occurring in 1948, when a 5-year-old boy died due to a ruptured stomach caused by swelling of the GI tract.² Post-mortem examination revealed the presence of gas and liquid in the stomach and abdominal cavity that smelled of alcohol.¹ At the time, the examiner hypothesized that this anomaly was the result of fermentation of sweet potatoes by gram negative intestinal flora;¹ blood ethanol concentration was not detected at that time.

Another early case involved a 24-year-old female in 1976 who, consistent with other reports, became intoxicated after consuming carbohydrates.³ She was given an antifungal agent while restricting her carbohydrate intake, leading to resolution of her symptoms.³ Despite continued investigation and case reporting, underlying mechanisms and causes of auto-brewery syndrome are far from being well understood.

What Side Effects Occur

Along with a state of intoxication, persons experiencing gut fermentation syndrome may also experience side effects such as dizziness, dry mouth, belching, chronic fatigue syndrome, hangovers, disorientation and irritable bowel syndrome.¹

Can It Be Treated?

The diagnoses of the syndrome is based on a host of factors such as an elevated BAC, symptoms of inebriation, GI cultures showing an elevated yeast burden, and an altered GI anatomy.² To treat it, decreased carbohydrate intake and high protein diets have been known to limit or diminish its symptoms.^1,2

Antifungal agents may also be prescribed should the symptoms not disappear with diet alone.^1,2 However, because symptoms have been known to resolve on their own, antifungal agents should be prescribed with caution due to their potentially adverse side effects.² Theoretically, other treatments might include surgical/medical management of any GI obstruction or hypomotility that would allow for auto-fermentation to happen.¹