What Is Auto-Brewery Syndrome (ABS)?
Auto-brewery syndrome is a rare condition that occurs when food ferments in your stomach and produces ethanol, the same alcohol found in alcoholic drinks. The condition can cause you to act like you’re drunk though you haven’t had any alcohol to drink.
If you have auto-brewery syndrome, also known as gut fermentation syndrome, your body has an unbalanced gut microbiome – the bacteria, fungi, and viruses in your intestines. When you eat too many carbohydrates, your gut makes too much alcohol and your liver can’t digest or metabolize it all and change it to useful energy for your body. As a result, alcohol builds up in your blood. This can produce the same effects as drinking too much alcohol.
Auto-brewery syndrome isn’t a very common condition. Less than 100 cases were reported worldwide in a 2021 report.
The syndrome has been described in medical research for more than 50 years, but researchers are still learning more about it. Many say the condition is widely underdiagnosed, meaning that more people have it, yet do not know. It can be very serious, especially if you have symptoms and get behind the wheel of a vehicle. If you are intoxicated and drive, it could hurt others, or you may be falsely accused of drunk driving. Additionally, you may start to crave alcohol more.
Here’s what to know about this condition and what you should do if you suspect that you or someone else has it.
Auto-Brewery Syndrome Symptoms
Symptoms of auto-brewery syndrome can be neurological, gastrointestinal, respiratory, and psychological. They’re similar to alcohol intoxication. They include:
- Unexplained intoxication
- Dizziness
- Disorientation
- Being uncoordinated
- Chronic fatigue
- Bloating
- Irritable bowel syndrome
- Slurred speech
- Gastrointestinal distress
- Being confused
- Memory loss
- Seizures
- Going into a coma
- Nausea
- Vomiting
- Glassy eyes
- Falling down
Auto-Brewery Syndrome Causes
Auto-brewery syndrome occurs when microorganisms in your gut break down carbohydrates into ethanol. That can cause intoxication without drinking alcohol.
The yeast species Saccharomyces cerevisiae and Candida albicans are the most common microorganisms involved in cases of auto-brewery syndrome. Others involved include S. boulardii, C. glabrata, C. albicans, C. kefyr, C. parapsilosis, Klebsiella pneumonia, Enterococcus faecium, E. faecalis, and Citrobacter freundii. The idea that a single strain is the sole cause of auto-brewery syndrome is an oversimplification because the syndrome is more complex, some experts say.
Risk factors for auto-brewery syndrome include:
- Diabetes
- Eating a lot of carbohydrates
- Alcoholism
- Taking antibiotics or proton pump inhibitors
- Imbalances of good and bad bacteria
- Genetics
- Pathology in your gastrointestinal tract
- Having non-alcoholic fatty liver disease
- Undergoing gastrointestinal surgery
- Crohn’s disease
- Short bowel syndrome
- Other autoimmune conditions
Auto-brewery syndrome can occur in healthy people as well.
If you have an underlying health condition, that can contribute to developing auto-brewery syndrome. People with short bowel syndrome, pseudoobstruction, or small intestinal bacterial overgrowth (SIBO) may be more likely to develop the syndrome.
Previous research shows people with auto-brewery syndrome tend to have poorer overall health. Other research finds those with the syndrome are more likely to drink more water; drink less tea, coffee, and dairy; and eat less candy. They’re more likely to have poor bowel movement quality, own pets, have more non-food allergies, and more food sensitivities.
In one study, people with the syndrome reported bad breath, bowel changes, and diarrhea. People with auto-brewery syndrome also report using antibiotics longer and also had more diagnosed gastrointestinal disorders.
Auto-Brewery Syndrome Diagnosis
If you start to act like you’re drunk but you haven’t had alcohol to drink, you may suspect auto-brewery syndrome. Some people don’t know it’s possible for people to be intoxicated without alcohol, so they may falsely accuse you of drinking. If a friend or family member acts intoxicated but claims they haven’t had alcohol, you can tell them about auto-brewery syndrome and suggest they see a doctor.
Doctors typically perform a few baseline tests including blood tests to check your metabolism as well as blood alcohol levels. The doctor may recommend fecal testing to see if yeast is growing in your body. Doctors will try to rule out other medical ailments that have similar symptoms, including neurological and psychiatric disorders. They may use an upper and lower endoscopy to test secretions and identify the specific microbe implicated in the syndrome.
A carbohydrate challenge test (or glucose challenge test) should be performed when your breath and blood alcohol levels are back to zero. The clinician will give you glucose orally and test your breath and blood at different intervals after you take it. If you have high levels of blood or breath ethanol after the test, that will confirm the diagnosis.
People who already had type 2 diabetes or cirrhosis of the liver may have higher levels of ethanol in their bodies already compared to people without the disease. This may complicate your diagnosis.
If you are diagnosed with auto-brewery syndrome, that can put you on the path to treatment. You’ll also be able to understand what’s behind feeling intoxicated without drinking. You’ll also be able to educate others about this rare condition.
Auto-Brewery Syndrome Treatment
A multidisciplinary team is ideal to manage auto-brewery syndrome. This can include a primary care doctor, gastroenterologist, infectious disease specialist, a nurse, and a nutritionist. If you have diabetes, you can add an endocrinologist to the list, while those with liver complications should consult a hepatologist. Managing auto-brewery syndrome requires lifestyle modifications and may require treatments.
If you need immediate care for auto-brewery syndrome, you’ll be treated for alcohol poisoning and stabilized by emergency medical personnel.
Once you know you have auto-brewery syndrome, the doctor may prescribe antifungal drugs to target the yeast or bacteria. Common medications prescribed include fluconazole, micafungin, nystatin, trichomycin B, and voriconazole. You’ll only get antibiotics if the culprit is a bacteria.
Your diet is also important to treat this syndrome, so you probably want to see a nutritionist. Eating too many carbohydrates can cause you to relapse, so you’ll need to follow a low-carbohydrate (low-carb) diet. Carbohydrates are sugars that are transformed into alcohol when you have this syndrome, so managing your sugar is important as well. During treatment, you’ll need to avoid sugars and carbohydrates and eat a high-protein diet. Some people who modified their diets didn’t need medication.
You should also reduce carbohydrate and sugar consumption after treatment.
In order to balance bacteria in your gut, you may take other supplements such as probiotics. It’s a good idea to know what to do in case you have to take an antibiotic because that can throw off the balance of microbes in your gastrointestinal tract.
Sometimes, people have additional yeast in their bodies that can resist the initial drug treatment.
If you have chronic relapses, your doctor may suggest a fecal microbiota transplant. This involves transplanting healthy bacteria from the feces of a screened donor into your body.
Auto-Brewery Syndrome Complications
After treatment, you can resume a normal diet for the most part but should be mindful about carbohydrate intake. Long-term exposure to the alcohol your body makes may cause you to crave alcohol and begin drinking (or drinking more). This can result in alcohol use disorder.
Some of the gut bacteria that play a role in alcohol production can be attributed to nonalcoholic steatohepatitis (NASH). In fact, a 2023 study comparing fecal samples in those with NASH to those without found elevated fecal ethanol and glucose levels in the NASH group.
Left untreated, auto-brewery can lead to non-alcoholic fatty liver disease (NAFLD) as well as NASH (a more severe form of NAFLD), as alcohol made in the body’s metabolism system plays a role in the development of both. In fact, one small study on 43 people with NAFLD showed that more than 60% had alcohol-producing bacteria in their gut. When researchers put that bacteria into mice, the mice developed NAFLD, too.
Some evidence suggests the syndrome can affect vitamin B6, zinc, and magnesium levels.
Friends and family can have a tough time coping with auto-brewery syndrome, too. It can create social and legal issues, as many people who don’t understand that it’s a medical condition may avoid you if you have it or pursue legal recourse. For example, if your alcohol levels are high when you're driving and you have an accident, you could face legal consequences (and need to prove that you have auto-brewery syndrome and were not drinking carelessly).
Some people who drink a little can have it, which makes the effects of alcohol even more pronounced. It may be harder to get a diagnosis in those cases because the person can pinpoint having had an alcoholic drink, which may cause clinicians to rule it out.
This is why clinicians are warned to be compassionate toward anyone who comes in who seems intoxicated but says they haven’t been drinking alcohol.
Living With Auto-Brewery Syndrome
If you live with auto-brewery syndrome, it’s best to stick to a low-carbohydrate diet to avoid a relapse. You may want to consult a nutritionist or dietitian to talk about your diet, including any supplements to take. Some people take probiotics regularly to manage their gut health and prevent a relapse.
Your doctor can discuss drinking alcohol with you, in terms of whether or not you should have alcoholic beverages as your body is prone to producing alcohol if you have auto-brewery syndrome.
It’s important to talk to family and friends to alert them if you have auto-brewery syndrome. This way, if you have a meal high in carbohydrates and begin to experience symptoms of intoxication, they’ll understand why.
Takeaways
Though auto-brewery syndrome is rare, this medical condition can be serious. If you have auto-brewery syndrome, your body contains microbes that cause your body to produce too much alcohol when you eat carbohydrates or sugars. As a result, your body can’t metabolize the alcohol and it causes symptoms of intoxication. In other words, you’ll act or feel similarly to having had too much alcohol to drink without having any alcohol at all.
The condition can be worrisome because being intoxicated can put your health and safety at risk – as well as the health and safety of others. You may behave inappropriately or get behind the wheel of a car. Friends and family members may think you have a drinking problem when you don’t. Social and legal consequences can follow.
Auto-brewery syndrome can be harmful for your long-term health, too. Too much alcohol can cause damage to your body, and you can experience episodes over and over just from eating certain foods. The condition is linked to NAFLD or NASH, which can cause a slew of symptoms and liver failure.
Auto-Brewery Syndrome FAQs
What triggers auto-brewery syndrome?
If you have an underlying health condition such as diabetes, you may be more likely to experience auto-brewery syndrome. Ultimately, the syndrome occurs because the food you eat ferments in your stomach, combining with certain gut microbes to make too much alcohol for your liver to handle (even when you haven’t had any alcohol to drink). When your body makes too much alcohol, your blood alcohol levels rise, which can lead to symptoms of traditional intoxication.
How do you fix auto-brewery syndrome?
There are ways to treat the condition, but there’s no standardized treatment. Your doctor may treat you for alcohol poisoning or give you an antifungal medication or an antibiotic depending on which microbe they think is causing the symptoms.
How rare is auto-brewery syndrome?
Less than 100 cases were reported across the globe, according to a 2021 report.
How do you test for auto-brewery syndrome?
Your doctor will check your blood alcohol levels if you’re having acute symptoms. Otherwise, you’ll likely go through several tests including bloodwork and fecal sample tests, as well as a glucose challenge test (also known as a carbohydrate challenge test) to see how your body is metabolizing sugars.
What does auto-brewery syndrome feel like?
If you have the syndrome, you may feel like you're drunk without having had any alcoholic beverages to drink.
What foods to avoid with auto-brewery syndrome?
People with auto-brewery syndrome should avoid carbohydrates, which are sugar molecules that your body converts to alcohol. Consult with a nutritionist or dietitian to get a better idea of what foods to avoid and which foods contain carbohydrates that you may be unaware of.
Can a breathalyzer detect auto-brewery syndrome?
A breathalyzer test can detect if you have too much alcohol in your system. Many people who fail a breathalyzer test and know they haven’t had a drink go on to be diagnosed with the syndrome.
Can you drive with auto-brewery syndrome?
You may be fearful to drive if you have auto-brewery syndrome, which is why getting a diagnosis is so important. Once you know you have auto-brewery syndrome, you can avoid high-carbohydrate meals to avoid a relapse.
