Quick answer: Short-chain fatty acids (SCFAs) are compounds your gut bacteria make when they ferment fiber. The main ones are butyrate, acetate and propionate. Butyrate fuels the cells lining your colon and helps keep the gut barrier tight, while acetate and propionate help regulate blood sugar, appetite and inflammation. Low SCFA production may be one factor in some people with brain fog, low mood, fatigue and ongoing gut symptoms.
Key takeaways
Short-chain fatty acids are made when gut bacteria ferment fiber, and the main ones are butyrate, acetate and propionate.
Butyrate fuels the cells lining the colon, while acetate and propionate play roles in appetite, blood sugar and inflammation signals.
Low production may connect with gut-brain symptoms, and more fiber and resistant starch are common ways to feed the bacteria that make them.
There are microbes in your gut constantly producing compounds that influence your mood, focus, energy, and even inflammation in the brain. One of the most important groups is the short-chain fatty acids.
What each short-chain fatty acid does
Butyrate
Butyrate is the primary fuel for the cells lining your colon. It helps strengthen the gut barrier (the tight junctions between cells), calms inflammation and supports healthy immune function. Emerging research suggests butyrate may also influence brain health, including signaling through the vagus nerve, the main communication highway between gut and brain.
Acetate and propionate
Acetate and propionate help regulate blood sugar, appetite and body-wide inflammation. When SCFAs are in balance, they contribute to better metabolic health and a calmer nervous system.
Signs SCFA production may be low
Signs that SCFA production may be low include brain fog, anxiety or mood swings, and low energy or chronic fatigue. Poor stress resilience and ongoing gut symptoms, even mild ones, can also be clues.
Low SCFAs often point to low levels of beneficial bacteria (such as Faecalibacterium, Roseburia or Akkermansia), not enough fiber, or other microbiome imbalances. Read more about how microbiome diversity is measured and the gut-brain connection.
SCFAs and healthy aging
Two processes that drive aging are chronic low-grade inflammation and dysbiosis, an imbalanced gut microbiome. Butyrate sits right where they meet: it helps keep the gut lining sealed so fewer bacterial fragments reach the bloodstream, and it helps calm the immune system. It also acts as a signaling molecule between gut cells and the rest of the body. A gut that keeps making SCFAs is one of the quiet foundations of aging well. Related: what is leaky gut?.
How SCFAs are measured
Some functional stool tests measure acetate, butyrate, propionate and total SCFAs, along with the bacteria that produce them. That data can move us from guessing to knowing in more complex cases. Functional labs are optional. They can be helpful in more complex cases.
How to support SCFA production
Fiber variety matters, from vegetables, legumes, oats, flax and green bananas to cooked-and-cooled potatoes or rice (resistant starch). Polyphenols from berries, green tea, olive oil and cocoa feed beneficial bacteria, and fermented foods such as yogurt, kefir, sauerkraut and kimchi can help if tolerated.
Targeted support with specific prebiotic fibers, probiotics or postbiotics (such as butyrate) can be added when appropriate. Lifestyle counts too, because sleep, stress management and movement all shape the microbiome.
Please discuss supplements with your provider first.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have brain fog, low mood or fatigue together with gut symptoms, or if fiber or probiotics make you feel worse instead of better. The same is true if you have tried diet changes with only partial relief, or if you want a personalized plan for your microbiome.
See a medical provider promptly for blood in the stool, unintended weight loss, persistent vomiting, severe abdominal pain or fever.
What the research shows
One of the few human trials to raise a short-chain fatty acid in the colon was a 2015 study by Chambers and colleagues. Researchers attached propionate to inulin fiber so it would be released in the colon. In a 24-week randomized trial, 60 overweight adults took 10 grams a day of this inulin-propionate ester or plain inulin. The propionate group gained less weight, had less fat around the organs and in the liver, and kept their insulin sensitivity, which worsened in the control group. It was a single trial of an experimental ingredient, not a food you can buy.
For the brain, the evidence is mostly from animals. A 2019 review by Dalile and colleagues summarized how short-chain fatty acids may act on the gut lining, immune cells, hormones and the vagus nerve to influence the brain, and noted that most of this comes from animal and lab studies, with few human trials. Eating more fiber is the most practical way to support SCFA production, but direct effects on mood and memory in people are still uncertain.
Gut and brain symptoms at the same time? Let us talk about what may connect them.
A free 15-minute consultation with Dr. Kneessi. No cost, no obligation. In-office in Odenton, MD or by telehealth.
Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Would a stool test that measures short-chain fatty acids help explain my gut and mood symptoms?
What might short-chain fatty acid markers be telling us, given my health history and symptoms?
Which other labs would be worth pairing with short-chain fatty acid markers to get a clearer picture?
When would it make sense to recheck short-chain fatty acid markers, and what could I work on in the meantime?
Frequently asked questions
What are short-chain fatty acids?
They are compounds made when gut bacteria ferment dietary fiber. The main ones are butyrate, acetate and propionate.
How can I increase butyrate naturally?
Eat a variety of fiber-rich plants, resistant starch (such as cooked-and-cooled potatoes or rice), and polyphenol-rich foods. Some people use butyrate supplements with guidance.
Do SCFAs affect mood?
Research suggests SCFAs influence the gut-brain axis through the immune system, the vagus nerve and gut hormones. Studies in humans are still developing.
Do I need a stool test to improve my SCFAs?
No. Many people start with diet and lifestyle changes. Testing can add detail in more complex cases.
Sources
- Chambers ES, Viardot A, Psichas A, et al. Effects of targeted delivery of propionate to the human colon on appetite regulation, body weight maintenance and adiposity in overweight adults. Gut 2015. PMID: 25500202. https://pubmed.ncbi.nlm.nih.gov/25500202/
- Dalile B, Van Oudenhove L, Vervliet B, et al. The role of short-chain fatty acids in microbiota-gut-brain communication. Nat Rev Gastroenterol Hepatol 2019. PMID: 31123355. https://pubmed.ncbi.nlm.nih.gov/31123355/
- Koh A, et al. From Dietary Fiber to Host Physiology: Short-Chain Fatty Acids as Key Bacterial Metabolites. Cell 2016. PMID: 27259147. https://pubmed.ncbi.nlm.nih.gov/27259147/
- Donohoe DR, et al. The microbiome and butyrate regulate energy metabolism and autophagy in the mammalian colon. Cell Metab 2011. PMID: 21531334. https://pmc.ncbi.nlm.nih.gov/articles/PMC3099420/
- Peng L, et al. Butyrate enhances the intestinal barrier by facilitating tight junction assembly via activation of AMP-activated protein kinase in Caco-2 cell monolayers. J Nutr 2009. PMID: 19625695. https://pmc.ncbi.nlm.nih.gov/articles/PMC2728689/
- López-Otín C, et al. Hallmarks of aging: An expanding universe. Cell 2023. PMID: 36599349. https://pubmed.ncbi.nlm.nih.gov/36599349/
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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