Scientists find treatment for rare ‘auto-brewery syndrome’ that turns digested carbs into alcohol

Eating a meal heavy in carbohydrates can easily make a person feel a bit off. Usually, it’s just feeling sleepy or full, maybe even some indigestion after eating multiple slices of pizza or a large sub sandwich. However, for some people, eating carbs can not only make them feel drunk, but actually make them drunk. Fortunately, scientists may have found a solution for them.

While rare, there are many people who are affected by “auto-brewery syndrome,” otherwise known as “gut fermentation syndrome.” Auto-brewery syndrome is when the gut bacteria within a person’s stomach ferments carbohydrates into ethanol during digestion, causing intoxication without any alcohol consumption. In other words, a person can become drunk after eating carbs like a plate of spaghetti or a breakfast bagel.

This condition can be very serious, as a person may become too intoxicated to drive or worse without even touching a cocktail. Many patients would visit doctors complaining about slurred speech, memory issues, and coordination issues after eating meals only to be accused of hiding alcohol consumption or outright alcoholism. For many patients, this misdiagnosis would cause strain professionally and personally until they were properly diagnosed with auto-brewery syndrome.

Prior to this study by the University of California San Diego and Massachusetts General Hospital, it was hypothesized that auto-brewery syndrome was caused by yeast in the digested food. However, they found that it was specific gut bacteria that was causing the fermentation. Upon that realization, the researchers were able to come up with an effective treatment.

The scientists observed 22 auto-brewery syndrome patients alongside 21 of their partners. While fungi couldn’t be ruled out entirely, the research found the primary culprits to be Proteobacteria phylum, including Escherichia coli and Klebsiella pneumoniae, which are common gut bacteria that can produce ethanol. The researchers found that the patients diagnosed with auto-brewery syndrome had higher Proteobacteria levels than their household partners.

The auto-brewery syndrome patients were also shown to have higher gene counts of three different metabolic pathways known to produce alcohol. The mixed fermentation pathway lets bacteria like E. coli convert to ethanol and succinate. The heterolactic fermentation pathway produces ethanol via acetyl phosphate as it metabolizes glucose. Lastly, the ethanolamine utilization pathway changes ethanolamine, a cell membrane compound, into ethanol. Evidence of these pathways were abundantly found in samples provided by auto-brewery syndrome patients.

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There is hope for these folks though. In order to offset the overgrowth of Proteobacteria and strengthen good bacterial strains in the digestive system, one case study saw researchers give an auto-brewery syndrome patient a fecal microbiota transplantation (FMT). FMT is a process in which stool from a healthy donor is transferred into a patient's gastrointestinal tract as a means to restore and promote the growth of healthy gut bacteria. This fecal transplant, along with antibiotics, can essentially gave the patient complete remission for three months. After a successful, more aggressive six month treatment with a monthly FMT schedule along with starch and probiotics, the patient was in full remission for over 16 months and was able to add carbs to their diet without any intoxication side effects.

Time and further experimentation will be needed to not only fully understand auto-brewery syndrome, but to find even better ways to help those who just want to enjoy meals like everyone else.