09/09/2025
If you’ve ruled out iron deficiency, thyroid issues, or neurological conditions but still feel mentally foggy, your gut may be the missing piece.
One overlooked cause of brain fog is the fermentation of sugars by yeast or bacteria in the gut, producing acetaldehyde and ethanol—both of which can impair brain function.
What Is Auto-Brewery Syndrome?
Auto-brewery syndrome (ABS), also known as gut fermentation syndrome, occurs when Candida or bacteria like Klebsiella ferment carbs into ethanol and acetaldehyde—without alcohol intake.
These byproducts:
- Cross the blood-brain barrier
- Interfere with neurotransmitters
- Slow mental processing, focus, and memory
Even healthy individuals may experience low-level fermentation, especially with a high-sugar, high-carb diet.
What Causes It?
ABS is more common in those with:
- Candida overgrowth (e.g., C. albicans, C. glabrata)
- Dysbiosis or SIBO
- High-carb diets or poor liver detox function
It’s also been linked to:
- Diabetes
- Liver disease
- Long-term antibiotic use
- Stress, poor sleep, and skipping meals
Symptoms May Include:
- Brain fog, fatigue, and disorientation
- Lightheadedness after meals
- Gas, bloating, or "hangover" feelings
- Behavioural changes or poor concentration
Dr. James Yoon provides care out of our Toronto clinic. Click the link below to learn more.
https://bit.ly/3VHjhse
REFERENCES
Painter K, Cordell BJ, Sticco KL. Auto-Brewery Syndrome. [Updated 2023 Jan 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. https://bit.ly/3HSxHCN
