Consumption of foods rich in carbohydrates such as pasta, bread or even potatoes amplifies the phenomenon.
Prosecuted for repeated drunk driving, a 40-year-old Belgian was acquitted in April 2024 after proving that he suffered from alcoholic self-fermentation syndrome. This phenomenon, also known as “intestinal fermentation syndrome” Or “auto-brewery” is extremely rare: a handful of people around the world are affected, and barely twenty in France since it was diagnosed. “In these patients, the body endogenously produces ethyl alcohol (ethanol) when they consume lots of carbohydrates (sugars) or high-carb foods like bread, pasta or potatoes explains Dr Joséphine Sérinet, general practitioner at the Alpha Alcoological Center in Royan (17). This phenomenon can lead to a state of intoxication (with a alcohol level can go up to 4 grams of alcohol per liter of blood) without any external alcohol consumption.
An imbalance of the intestinal microbiota involved
This syndrome can have several causes. “These causes are generally linked to factors that disrupt the balance of intestinal flora or promote the excessive growth of yeast (fungi) in the digestive system” continues the doctor. “The balance between different species of bacteria and yeast in the gut is crucial for healthy digestion.” Any factor that can disrupt this balance can promote excessive growth of alcohol-producing yeasts. “Certain types of yeast, particularly species in the Candida family (such as Candida albicans), are capable of fermenting sugars found in foods and producing alcohol.” An overgrowth of these yeasts is often the direct cause of self-fermentation syndrome.
Excess antibiotics promote self-fermentation
Among the factors that can disrupt the balance of the intestinal flora, we can cite antibiotics. “When consumed repeatedly and for a long time, antibiotics will destroy beneficial bacteria which control yeast growth, promoting yeast proliferation and self-fermentation” underlines Dr. Sérinet. We think, for example, of adolescents who follow antibiotic treatments for acne for several months. Some intestinal diseases are also involved: “This is the case of irritable bowel syndromeof the Crohn’s diseaseulcerative colitis, an intestinal or gastric tumor or even operations such as Bypass or the sleeve which can create a favorable environment for yeast growth and fermentation.” Finally, certain metabolic diseases, such as diabetes, can cause an increase in the concentration of glucose in the intestines, which provides additional substrate for yeast fermentation.
Symptoms of intoxication without drinking alcohol
Although the patient suffering from self-fermentation-alcoholic syndrome has not ingested a single drop of alcohol, his condition is nevertheless comparable to that of a person who has drunk it. “Depending on the level of alcohol produced by the body, the person may feel a feeling of inebriation, headache, nausea and fatigue. But depending on the amount of carbohydrates consumed, she may develop confusion, dizziness and slurred speech.” If the syndrome is not treated, we can eventually see an effect of tolerance to alcohol and therefore a risk of dependenceof cirrhosis, high blood pressure or neurological damage or hepatitis. Diagnosis may be late, because the disease remains very rare.
“In all cases, the breathalyzer will be positive”
“In all cases, the breathalyzer will be positive, assures our interlocutor. It can be supplemented by a glucose challenge test.” The patient will orally ingest a solution with 200 grams of glucose and his ethanol level will be measured by breathalyzer or blood test at 30 minutes, then 1 hour, 4 hours and 8 hours. “In certain cases, a fibroscopy and/or a biopsy may be performed to collect gastrointestinal secretions for bacterial and fungal cultures.”
Treatments aim to restore the balance of the microbiota
Treatments depend on the cause. “If the syndrome is linked to taking antibiotics, the patient must, under the supervision of their doctor, immediately stop the treatment” alerts Dr. Sérinet. In the event of gastrointestinal diseases or diabetes, specific treatment will be offered. “In addition, probiotic supplements containing beneficial bacteria can help restore the balance of intestinal flora and reduce excessive yeast growth. Frequently, antifungal medications may be prescribed to reduce the yeast population in the digestive system.” A low-carbohydrate diet is also implemented. “Finally, in certain cases, psychological support can be beneficial, particularly if the person needs to go through withdrawal or has chronic alcohol-related disorders.”