The human body contains roughly ten trillion cells — and roughly 100 trillion bacteria. These bacteria — life forms in their own right — constitute as much as 2% of our body mass. Most of the bacteria operate, effectively, independent of us, having little to no effect on our health or well-being. Some are actually symbiotic, likely aiding in the digestion of food and perhaps even making us smarter (although that study is controversial). Others are harmful — one type may make depression symptoms worse while others cause illnesses such as strep throat.
And others turn our stomachs into breweries. Well, once at least.
Sometime in the late summer or early fall of 2013, a 61 year-old Texas man walked into an emergency room drunk out of his mind. Nurses administered a Breathalyzer exam and determined that the patient’s blood-alcohol level was a 0.37 (which can lead to serious impairment). Normally he’d be given some time to sober up. But there was one weird variable in this case: the man hadn’t been drinking. And to make sure that he wasn’t sneaking a shot or two, doctors searched him for booze and, finding none, stuck him in a hospital room, alone, for 24 hours. He was given food like any other patient — a normal diet, no vodka or anything like that — as medical professionals kept monitoring his blood alcohol level. While most people would sober up, the man actually got more drunk. His blood alcohol level went up 12%.
The cause was a bacteria known as Saccharomyces cerevisiae, more commonly known as “baker’s yeast” or “brewer’s yeast.” As the Environmental Protection Agency notes, not only is the microorganism typically harmless, but it’s also particularly useful. It has been used for centuries as a leavening agent for bread and a fermenting agent for alcohol. Saccharomyces cerevisiae infections are unheard of, too, as the bacteria almost always pass through the human body without issue.
But in this case, something was amiss. As NPR reported, a significant amount of Saccharomyces cerevisiae had taken residence in the patient’s gut. The reasons why were unclear at best, but the result — termed “auto-brewery syndrome” — was striking. Whenever the man ate anything starchy — “a bagel, pasta, or even soda” are the examples NPR gave — the man was also feeding the Saccharomyces cerevisiae. The bacteria churned through the carbohydrates and released ethanol as a byproduct. The man was brewing beer in his own stomach — and getting drunk off it, too.
The two doctors who discovered this curiosity published a paper on the topic in the International Journal of Clinical Medicine, but as others have pointed out, the doctors weren’t performing a controlled study nor did they have more than one person — and therefore more than one data point — to work off of. Why the Saccharomyces cerevisiae took root in the man’s stomach remains unknown, but it’s treatable — an antifungal medicine called fluconazole will kill off the intrusive microbes. (But sorry, it won’t help you sober up after a night out.)