Several years ago, a woman in New York was charged with a DUI when police officers found her blood alcohol level to be four times the legal limit. Fast forward, and she was acquitted of the charge, due to the diagnosis of a rare condition called “auto-brewery syndrome.” The condition causes microbes in the intestines to produce unusually high levels of alcohol when they break down sugars and carbohydrates. While the condition is rare and this case was extreme, it led to questions about the possibility of intestinal microbes influencing health and behavioral traits.
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According to a new study published in Cell Metabolism, an intestinal microbe that produces high levels of alcohol may in fact lead to fatty liver disease. While most people associate fatty liver disease with alcoholism, there are a number of factors that can contribute to the condition, including obesity, insulin resistance and hepatitis C. The discovery that intestinal microbes may also cause the disease occurred when physicians identified a patient who was suffering from both conditions — auto-brewery syndrome and severe NAFLD. Stool samples from the patient revealed a bacteria known as Klebsiella pneumoniae. The bacteria in the patient was producing 4 to 6 times the alcohol that it produces in people who are healthy.
The discovery led study author Jing Yuan and her team to examine 43 other NAFLD patients. They found that in 61%, the bacteria were excreting excessive amounts of alcohol. The researchers noted that the bacteria were only slightly more abundant in the NAFLD patients’ intestines, but the quantity of alcohol produced by the microbes was the biggest difference.
To help pinpoint cause and effect, the researchers fed the bacteria to healthy mice. Within a month, the mice developed symptoms of fatty liver. Within two months, it had progressed to cirrhosis. When the researchers fed the mice pure alcohol, the progression timeline was the same. Researchers concluded — for the first time — that certain K. pneumonia bacteria make excessive alcohol, and it can lead to fatty liver.