The Hidden Link Between Your Gut and Your Brain: Short-Chain Fatty Acids (SCFAs)
By Dr. Ryan Kneessi
There are microbes in your gut that are constantly producing compounds that directly influence your mood, focus, energy, and even inflammation in the brain.
One of the most important groups of these compounds are short-chain fatty acids. These primarily include butyrate, acetate, and propionate.
Here’s What They Do
Butyrate
Butyrate serves as the primary fuel for the cells lining your colon. It strengthens the gut barrier (tight junctions), reduces inflammation, and supports healthy immune function. Emerging research also shows butyrate can influence brain health by promoting neurogenesis (the growth of new brain cells) and helping regulate the vagus nerve — the main communication highway between gut and brain.
Acetate and Propionate
Acetate and Propionate help regulate blood sugar, appetite, and systemic inflammation.
When these SCFAs are in balance, they contribute to better metabolic health and calmer nervous system tone.
Functional Testing for SCFAs
Functional labs can measure your levels of acetate, butyrate, propionate, and total SCFAs — along with the specific bacteria that produce them.
Low SCFA Production Is Common In Patients Dealing With:
- Brain fog
- Anxiety or mood swings
- Low energy / chronic fatigue
- Poor stress resilience
- Ongoing gut symptoms (even if mild)
When SCFA levels are suboptimal, it often points to low beneficial bacteria (such as certain Faecalibacterium, Roseburia, or Akkermansia species), inadequate prebiotic fiber intake, or other imbalances in the microbiome.
The Good News
Once we see the exact data, we can create a targeted plan — specific fibers, fermented foods, probiotics/postbiotics, and lifestyle adjustments — to help restore production naturally.
This is exactly why I love functional testing: it moves us from guessing to knowing.
If you’ve been struggling with any gut-brain related symptoms and want deeper insight,
Functional Medicine Practitioner
