A Guide to Auto-Brewery Syndrome

Imagine waking up with symptoms of a hangover—dizziness, nausea, and a foggy mind—without having had a single drink. This is the perplexing reality for individuals with Auto-Brewery Syndrome (ABS), a rare and often misunderstood medical condition. Also known as gut fermentation syndrome, ABS occurs when certain types of yeast in the digestive system convert carbohydrates into alcohol, leading to elevated blood alcohol levels without the person consuming any alcohol.

The condition can be bewildering and frustrating, as it often goes undiagnosed or misdiagnosed, leaving sufferers to grapple with unexplained symptoms. Because ABS is so rare, many healthcare professionals are unfamiliar with it, which can delay diagnosis and treatment.

This guide aims to shed light on Auto-Brewery Syndrome, providing a comprehensive overview of what it is, what causes it, and how it can be managed. Whether you’re someone experiencing these mysterious symptoms, a healthcare provider, or simply curious, this guide will help you understand the intricacies of this unique condition.

What is Auto-Brewery Syndrome?

Auto-Brewery Syndrome (ABS), also known as gut fermentation syndrome or endogenous ethanol fermentation, is a rare medical condition in which the body produces alcohol internally, without the consumption of any alcoholic beverages. This occurs when certain types of yeast, most commonly Saccharomyces cerevisiae, ferment carbohydrates in the digestive system, producing ethanol as a byproduct. 

This ethanol is then absorbed into the bloodstream, leading to elevated blood alcohol levels and symptoms typically associated with alcohol intoxication. Individuals with ABS may experience a range of symptoms, including dizziness, confusion, fatigue, and a lack of coordination. 

A CNN news report wrote, “Her breath reeked of alcohol. She was dizzy, disoriented and weak, so much so that one day she passed out and hit her head on a kitchen counter while making lunch for her school-age children.” Dr Fahad Malik, a gastroenterologist at United Health Services in Binghamton, New York, currently treating 30 patients with Auto-Brewery Syndrome, notes that patients often face disbelief and ridicule. Many are initially dismissed as “closet drinkers” or assumed to have behavioural issues before receiving a proper diagnosis.

Causes and Risk Factors

Auto-brewery syndrome (ABS) is a rare condition with several underlying causes and contributing factors. 

Yeast Overgrowth

The primary cause of ABS is an overgrowth of yeast, particularly Saccharomyces cerevisiae, in the gut. This yeast is responsible for fermenting carbohydrates into ethanol, which is then absorbed into the bloodstream.

Gut Flora Imbalance

A healthy balance of gut bacteria is crucial for proper digestion. An imbalance in gut flora, often due to antibiotics or other medications, can allow yeast to proliferate and produce excessive alcohol.

Diet High in Carbohydrates and Sugars

Diets rich in carbohydrates and sugars provide the necessary fuel for yeast to produce alcohol. Individuals with ABS may notice symptoms worsening after consuming high-carb meals.

Alcohol Abstinence

Ironically, some individuals who abstain from alcohol may still experience symptoms due to the internal production of ethanol. This can be particularly confusing and distressing for those affected.

Diagnosis of Auto-Brewery Syndrome

Accurate diagnosis is essential for proper treatment and management. Here’s an overview of the diagnostic process:

• The first step in diagnosing ABS involves a thorough review of the patient’s symptoms and medical history.
• One of the most direct methods for diagnosing ABS is through blood alcohol testing.
• In a controlled setting, a carbohydrate challenge test may be performed. The patient consumes a meal or beverage high in carbohydrates, followed by periodic blood alcohol testing.
• Analysing the patient’s stool can help identify the presence and concentration of yeast, such as Saccharomyces cerevisiae.
• Portable breathalyser tests can be used by patients at home to monitor alcohol levels.

However, Auto-Brewery Syndrome (ABS) is not specifically listed as a separate condition in the ICD-11, which is the World Health Organization’s (WHO) latest version of the International Classification of Diseases. One person reports, “I asked a few doctors and specialists to check whether I had the syndrome, but ran into some walls; because it isn’t well known. I was able to ‘self diagnose’ (as a negative) by buying a home breathalyser device. It cost me about $10 or so. By measuring your blood alcohol content (when you haven’t been drinking), if the reading comes back as 0.00, you can be confident that you don’t have the condition.” The rarity and complexity of the condition contribute to its absence as a separate entry in the ICD-11 classification.

Living with Auto-Brewery Syndrome

Living with Auto-Brewery Syndrome (ABS) can be challenging due to the unpredictable nature of the condition and its impact on daily life. Research indicates that patients with Auto-Brewery Syndrome are often identified either by a vigilant family member noticing unusual symptoms or after being arrested for a suspected DUI despite not consuming alcohol.

Managing ABS involves a combination of dietary adjustments, medical treatments, and lifestyle changes to minimise symptoms and improve quality of life. 

Dietary Management

• Low-Carbohydrate Diet: Since carbohydrates fuel the fermentation process that leads to alcohol production, a diet low in carbohydrates and sugars is essential. 
• High-Protein Foods: Emphasizing protein-rich foods can help stabilise blood sugar levels and reduce the likelihood of fermentation.

Medical Treatment

• Antifungal Medications: Doctors may prescribe antifungal medications to reduce the yeast population in the gut. 
• Probiotics: Probiotics may be recommended alongside antifungal treatment to promote the growth of healthy bacteria and prevent yeast overgrowth.

Lifestyle Adjustments

• Stress Management: Stress can exacerbate ABS symptoms, so incorporating stress-reducing activities such as yoga, meditation, or regular exercise can be beneficial.
• Avoidance of Triggers: Identifying and avoiding specific triggers, such as certain foods, beverages, or situations that increase symptoms, is important for managing ABS.

 Social and Psychological Impact

• Coping with Misunderstanding: People with ABS may face scepticism or misunderstanding from others, particularly if symptoms are mistaken for alcohol consumption. 
• Mental Health Support: The challenges of living with ABS can lead to anxiety, depression, or social isolation.

Treatment Options

Auto-Brewery Syndrome (ABS) is a complex condition that can be managed effectively with the right treatment plan, but it is not always completely curable. Treatment success varies depending on the underlying causes, the severity of the condition, and the patient’s adherence to treatment protocols. Many patients can achieve significant symptom reduction and lead relatively normal lives, but some may require ongoing management to prevent recurrence.

Antifungal Medications

Antifungal drugs are often the first step in treating Auto-Brewery Syndrome (ABS) due to the overgrowth of yeast in the gut, which is a common cause of the condition. Medications like fluconazole or nystatin are prescribed to reduce the yeast population. 

Antibiotics

In cases where bacterial overgrowth contributes to ABS, antibiotics may be prescribed. However, careful management is needed to avoid disrupting the gut microbiome, which could lead to further yeast overgrowth.

Probiotics

Probiotics help restore a healthy gut balance, which is crucial in managing ABS. Supplements or fermented foods containing Lactobacillus and Bifidobacterium strains can suppress ethanol-producing yeasts and support overall gut health.

Dietary Changes

A low-carbohydrate diet is essential to reduce the fuel for fermentation which leads to ethanol production.

Case Study

This case study was published by Akhavan and Bobak in 2019. A 25-year-old man with no significant medical history presented with a complaint of feeling “drunk without drinking.” He reported that his usual one or two 12-ounce beers caused him to feel inebriated, and this sensation progressed to occurring even without alcohol consumption. His symptoms, which included slurred speech, fatigue, stumbling, dizziness, and nausea, occurred 1–2 times per week and typically resolved by morning. 

Despite an unremarkable physical examination and normal vital signs, his elevated lactic acid levels and blood alcohol concentrations during symptomatic episodes suggested an underlying issue. Extensive testing, including urine drug screens, metabolic panels, liver function tests, and thyroid studies, yielded no abnormalities, and a celiac disease workup and hypoglycemia tests were inconclusive.

In outpatient care, both a gastroenterologist and endocrinologist found no definitive cause. A breathalyser test conducted by his wife revealed that his blood alcohol concentration was elevated during symptoms but normal otherwise, supporting the diagnosis of the auto-brewery syndrome. An empiric trial of oral fluconazole 100 mg daily for three weeks effectively resolved his symptoms, with no further episodes reported in follow-up, confirming the diagnosis and successful treatment.

If you experience similar symptoms, it is crucial to seek medical advice for a thorough evaluation. Understanding such rare conditions is essential for accurate diagnosis and effective treatment.