Auto-brewery syndrome is a rare condition, first discovered in the 1940s, in which a person experiences alcohol intoxication by creating alcohol in their own body. These individuals do not drink alcohol, yet their body produces alcohol through “abnormal gut fermentation,” which basically means that their body makes alcohol out of regular food and drinks containing carbohydrates by fermenting it in the intestine with yeast or bacteria that live in that part of the body.

The condition is also sometimes called “endogenous ethanol fermentation.”

Auto-Brewery Syndrome Symptoms

There are many symptoms resulting from the condition,﻿﻿ and perhaps surprisingly to those who drink alcohol recreationally, they are not pleasant. They include:

Problems with concentration, memory, and thought processes

Fatigue or feeling very tired

Aches and pains

Stomach pain

Bloating, gas

Changes in bowel movements

Discharge from the nose, a productive cough, and sinusitis

Sugar cravings

Causes

Fermentation in the gut is a normal part of the digestive process and happens through the breakdown of food by normal bacteria in the colon. However, in people with auto-brewery syndrome, fermentation happens in the small intestine, further up the digestive tract. Certain fungi have been found to be responsible for producing alcohol, such as Candida glabrata and Saccharomyces cerevisiae.﻿﻿

When someone with this condition consumes high-starch foods like pasta or bagels, the excessive yeast in the digestive tract then ferments the starch sugars into ethanol.

Normally, the liver can detoxify the tiny amounts of alcohol which are by-products of yeast fermentation, but in people with abnormal gut fermentation, too much alcohol is produced and causes the person to become intoxicated.

Research suggests that the condition may be linked to the use of antibiotics, which can wipe out normal gut-bacteria and allow yeast to thrive.﻿﻿

Risk Factors

Although the condition is very rare, cases have been reported in men, women, and children. There have been reports in several different countries, including Africa, Japan, the United States, Canada, and the United Kingdom.

While auto-brewery syndrome can occur in healthy individuals, it is most prevalent in people with the following comorbid conditions:﻿﻿

Diabetes

Obesity-related liver disease

Chrohn's disease

Short bowel syndrome

A weakened immune system or autoimmune condition

Antibiotic use, particularly if it is frequent or long-term, may interfere with the gut's natural microbiome and contribute to yeast overgrowth.

Diet may also play a role in the condition. Research suggests that people with auto-brewery syndrome are also more likely to report eating a diet high in sugar and carbohydrates.﻿﻿

If a patient has elevated blood alcohol levels or tests positive on a breathalyzer test without drinking alcohol, ABS should be considered. A person can also test themselves buy purchasing a breathalyzer; if they haven't consumed alcohol and the results are positive, it's likely ABS.

Associated Complications

There are several types of problems that can occur as a result of the condition. As well as the unpleasant symptoms of the disease, people may experience social and relationship problems as a result.

Friends, family, and co-workers may believe the person is a heavy drinker, and as denial is common among people who drink too much, denying that they have been drinking may not help.

A 13-year-old girl with the condition was thought to be showing adolescent behavior disorder, including both her symptoms of intoxication and her denial of drinking any alcohol, but, after being restricted from access to alcohol in a rehab center, showed the same signs and symptoms of drunkenness.﻿﻿

Some people have even got in trouble for drunk driving, as the alcohol may show up on a breathalyzer test. For example, on case study reported on a man in his early 40's who was pulled over for suspected drunk driving. While he insisted he had not been drinking, he had a blood-alcohol level of 0.2%, approximately 2.5 times the legal limit. It was only years after the man's arrest that he discovered that he had auto-brewery syndrome.﻿﻿

There are also physical problems that can develop, in particular, the small intestine may become more permeable, causing deficiencies in B vitamins, zinc and magnesium.﻿﻿ These vitamins and minerals are important in maintaining good health, and not having enough is a type of malnutrition.

Diagnosis

Because auto-brewery syndrome is so rare, it's diagnosis is frequently just as unusual. People often only become aware of the condition after failing a breathalyzer test. In other instances, people may seek help from a doctor for symptoms commonly associated intoxication, even though they have not been drinking.

The condition is usually diagnosed with a combination of lab tests and observation. This usually starts by taking a medical history of the individual's past and current symptoms and health status. The individual may be observed for a period of time to monitor their alcohol intake and their blood alcohol levels may be checked periodically. Stool samples may also be taken to look for abnormal fungi and bacteria levels.

Additional tests may be used to help rule out other underlying conditions or gastrointestinal disorders.

Treatment

Because the condition is so uncommon, there are no large-scale studies to look at effective treatments. However, case studies suggest that antifungals, dietary changes, and supplements may minimize or even eliminate the condition.

The main treatments for the condition are changes to diet to reduce intake of simple sugars, refined carbohydrates, yeast products, and moldy foods, and medications to reduce the fungi and bacteria thought to be responsible in the gut.﻿﻿

Vitamin and mineral supplements may also be needed to address the deficiencies in these nutrients.

In a 2019 study published in the journal BMJ Open Gastroenterology, researchers suggest that the condition is treatable with the use of antifungal therapies and dietary modifications.﻿﻿

They also suggest that probiotic supplements and treatments such as fecal microbiota transplantation may have promise, although further research is needed.

A Word From Verywell

Auto-brewery syndrome is an uncommon condition that has risen to prominence in recent years thanks to news reports and case studies. However, further research is needed to learn more about its causes and possible treatments. If you suspect you might have this condition, talk to your doctor.