Auto-Brewery Syndrome: What You Need To Know

Friends, foes, and frenemies live out their microbial lives in our gut. 

They have progeny, scavenge for nutrients, communicate, and sometimes spar with other tenets and immune cells. Occasionally, they pick up craft brewing as a hobby and stir up trouble.

Auto-brewery syndrome (ABS), also known as gut fermentation syndrome, is a rare, likely often missed, and definitely understudied condition where the microbiome makes alcohol using dietary carbohydrates. 

According to a review published in the United European Gastroenterology Journal, the microbial culprits in most available case studies were various Candida species, Saccharomyces cerevisiae, and Klebsiella pneumoniae. However, there is a lot left to learn. Authors of a 2021 article from Practical Gastroenterology found less than 100 published case reports to study for their review and proposed diagnostic process and treatment.  

A 2021 Review in the Journal of Clinical Medicine notes gastrointestinal surgeries likely to cause short bowel syndrome such as resections for inflammatory bowel disease or necrotizing enterocolitis, antibiotic use, immunosuppression, diabetes, gastroparesis, and liver disease such as NAFLD or NASH are often comorbidities. The researchers anticipate that interventions or conditions that decrease stomach acid or promote rapid digestion of lots of carbohydrates and/or stagnation or backflow of gastrointestinal contents make a more favorable environment for the problematic microbes to flourish and practice their pesky craft. 

ABS causes gastrointestinal, neurological, and psychological symptoms, and symptoms of excessive alcohol intake according to a 2021 review and National Library of Medicine summary.

These symptoms include:

• GI: nausea, vomiting, diarrhea, irritable bowel syndrome, abdominal pain or discomfort, bad breath or “fruity” breath, belching, xerostomia, liver damage
• Neurological: slurred speech, seizures, falls and decreased coordination, blurry vision, fainting, memory problems, ataxia or walking difficulties
• Psychological: disorientation, bizarre behavior, somnolence, depression, confusion, chronic fatigue, feeling intoxicated, decreased social inhibition, decreased productivity, brain fog
• Other: hangovers, sinusitis, cough

ABS is dangerous for both the sufferer and their community.

The effects of chronic alcohol exposure have similar consequences, whether or not an individual is knowingly partaking. Over time, experts note ABS can damage the gut and liver, increasing the risk for cirrhosis, fatty liver disease, and pancreatitis. And it can lead to social and legal problems due to working or driving while intoxicated.

Experts proposed diagnosing ABS after ruling out other conditions in someone with a positive breath alcohol test in a 2021 article in Practical Gastroenterology. They emphasized:

1. Excluding alcohol consumption
2. Sampling gut microbiome contents to identify the culprit microbe and its sensitivity to treatment options
3. Confirming ABS with a carbohydrate challenge test 

They considered other blood tests helpful as well to evaluate vitamin status, such as folate and thiamine, as well as metabolic and liver function.

An individual with a high blood alcohol level due to ABS should be treated first for the alcohol poisoning according to a StatPearl summary available from the National Library of Medicine, and then is usually treated with an antifungal or antibiotic suited to the identified causal microbe, as well as a carbohydrate-restricted diet. Strategic probiotics are also used during and after treatment by experts. Relapses are possible, especially after antibiotics, so it is best to work with the healthcare team to make a plan to monitor for and hopefully prevent relapse. For those with chronic relapses, fecal microbiota transplants are a possible treatment, however, they are not without risks. 

Work with an RD if your doctor recommends a carbohydrate-restricted diet for ABS. Limiting the total amount and specific carbohydrates can be an important adjunctive treatment for ABS. But your RD and healthcare team will determine the appropriate duration, exact recommended limits, and reintroduction or retesting schedule for your unique case.

According to a 2021 article in Practical Gastroenterology, nutrition treatment for ABS will likely include:

• Avoiding alcohol.

• Avoid concentrated sugar sources such as sugar-sweetened beverages (tea, lemonade, sodas, sweetened coffee drinks, etc.), juices, sugary desserts, and added sugar or syrups. 

• Avoiding or limiting refined carbohydrates such as refined grains and pastries.

• Plenty of protein from sources such as fish, poultry, seafood, eggs, nuts, seeds, and lean meat.

• Plenty of fat from sources such as fatty fish, olive oil, avocado oil, nuts, seeds, and olives. 

• Enough Calories, vitamins, minerals, fiber, and phytonutrients to correct deficiencies and support the healing process, especially liver function, metabolism, and immune health.

• The right restricted amount of strategic complex carbohydrates for your unique case and treatment timeline. Be sure to work with your RDN and healthcare team to determine what is right for you at each step of your treatment.

1. _{Bayoumy, A. B., Mulder, C., Mol, J. J., & Tushuizen, M. E. (2021). Gut fermentation syndrome: A systematic review of case reports. United European gastroenterology journal, 9(3), 332–342.}
2. _{Malik, F., Wiskremesinghe, P., & Saleem, A. (2021). Auto-Brewery Syndrome: A Schematic for Diagnosis and Appropriate Treatment. Practical Gastroenterology: Nutrition Issues in Gastroenterology. 212, 10-20.} 
3. _{Painter, K., Cordell, B.J.,& Sticco, K.L. Auto-brewery Syndrome. (2022). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.}
4. _{Dinis-Oliveira R. J. (2021). The Auto-Brewery Syndrome: A Perfect Metabolic "Storm" with Clinical and Forensic Implications. Journal of clinical medicine, 10(20), 4637.}