It was a beautiful October day when she got arrested.
In 2014, a New York schoolteacher was detained near Buffalo for erratic driving. A Breathalyzer test revealed a blood-alcohol level more than four times the legal limit. She failed other sobriety tests, too.
A few months later, the court dropped her drunk driving charges. Her defense? Auto-brewery syndrome. She wasn’t drunk because she drank alcohol, it was because she made the alcohol. Her own gut was fermenting ethanol and intoxicating her.
It almost sounds too convenient, like a get-out-of-jail-free card, but it’s not fiction — it’s science. And, while this is a rare condition, it might happen more often than we think.
Brewing your own alcohol — it’s real and this is why we need to know about it:
The inner brewery: How auto-brewery syndrome works
When you think of a brewery, large tanks, barrels, and the rich aroma of hops come to mind. But, the fermentation process can actually happen anywhere, including your own body.
Auto-brewery syndrome (ABS) is a condition where the human gut becomes an unwilling host to this internal fermentation process. It’s a microscopic brewery operating in your digestive system. Here’s how it happens:
At its core, fermentation is a process where microorganisms break down substances to produce energy.
Yeast can ferment sugar molecules into ethanol (grain alcohol — the same thing in your favorite beer, wine, or spirit) and carbon dioxide. We have used this process to make liquor for as long as humanity has enjoyed fun beverages.
In auto-brewery syndrome, this happens in your gut. A disruption (or a series of disruptions) makes microbes go rogue and convert sugars into ethanol. You’re affected by that ethanol the same way a glass of wine would affect you. You get drunk without ever drinking.
The microbial culprits
In his review on the condition, toxicologist Ricardo Dinis-Oliveira, PharmaD, PhD, a researcher at the University of Porto in Portugal, calls it “a perfect metabolic storm.” In most cases, this isn’t the work of a single mischief-maker. A variety of yeast and bacteria can be responsible for the uninvited fermentation fest.
Yeasts like Candida and Saccharomyces are often considered the prime suspect. Where did they come from? For most people with ABS, they had taken an antibiotic before the condition came about. This killed off some bacterial strains and allowed the yeasts to overgrow, causing auto-brewery syndrome.
Let’s look at one fairly typical real case of ABS (keep in mind this is still a rare condition). We have a middle-aged man who:
- Hurt his thumb in 2011 and got treated with an antibiotic.
- Experienced mental health issues and was started on an antidepressant in 2014.
- Later in 2014, he was driving while intoxicated but said he didn’t have any alcohol.
- He started monitoring himself with a breathalyzer — even when he wasn’t drinking, his blood alcohol level would go up.
- Brewer’s yeast was detected in his stool. Later on, doctors found two additional yeast strains.
Eventually, physicians got him on anti-fungal medication and a low-carb diet (carbs are what feed the yeast and turn it into alcohol) and that resolved his symptoms. Yes, it even helped the mental health problems he was experiencing.
But not everyone with ABS has brewer’s yeast in their intestines. Bacteria like Klebsiella pneumoniae have also been implicated, especially in people with liver problems. In fact, this alcohol-producing bacteria can cause the liver issue to begin with — people were getting liver damage without drinking, simply because of their microbial disbalance.
Who gets auto-brewery syndrome?
ABS can happen in a healthy person. One of the earliest reported cases was a 24-year-old nurse who didn’t overeat and didn’t have any underlying conditions. But, for the most part, people with auto-brewery syndrome have another health issue like:
- Type 2 diabetes
- Liver conditions
- Crohn’s disease
- Obesity
One case-control study identified additional problems. ABS patients described themselves as less healthy, had more food sensitivities, complained of bad breath and bowel movement issues more often.
Like the guy from the case above, many were treated with an antibiotic. Because antibiotics can’t tell good from bad bacteria, they significantly disrupt the microorganisms in your gut. When the good guys are scarce, fungi like Candida and Saccharomyces can run rampant.
Finally, carbohydrates play a major role. Alcohol-producing microorganisms feed on carbs and turn them into ethanol. A high-carb diet gives them more material and makes the condition worse.
For the nurse from the report, she was eating a 78% carb-based diet (current guidelines say 45–65% of your diet should be carbs). The man in the first report was recovering until he had a pizza and soda during treatment. All of his symptoms relapsed and he had to go through another round of antifungals.
ABS patients often need months of nutritional support until they can safely reintroduce carbs in their diet.
What does this mean for the rest of us?
Auto-brewery syndrome is an interesting condition and it’s probably underdiagnosed because symptoms vary, most of us do drink alcohol (making it hard to say if intoxication was from ABS), and most doctors don’t know about it/don’t test for it first.
Even if we are missing some cases, though, it’s rare for your body to start brewing its own alcohol. But, it’s not rare for people to eat a high-carb diet or to get prescribed antibiotics. We’re also in the middle of an obesity epidemic and type 2 diabetes is on the rise.
ABS is a rare condition that illustrates common gut health errors we commit. To keep your microbiome healthy (and avoid the bad guys from taking over):
- Get to a healthy weight.
- Avoid taking antibiotics without need.
- If you’re prescribed an antibiotic, complete the course and follow up with a probiotic.
- Reduce carbs in your diet, especially fast carbs like sugar and white flour.
- Stay on top of any chronic conditions you might be dealing with. If you have diabetes, work to manage your blood sugar, if you’re struggling with liver disease — follow your doctor’s prescription and lifestyle suggestions, etc.
Microbiome-related conditions like ABS can teach us a lot about keeping our gut bacteria healthy. Let’s not wait for things to get out of whack — your microbiome will appreciate the help now.
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