Just like your car needs gas to run, your colon needs short-chain fatty acids to operate. Short-chain fatty acids (SCFAs) are energy sources for our colonic tissues produced through the bacterial fermentation of dietary fibers. These dietary fibers include pectin from apples and resistant starches found in legumes such as beans, lentils, oat bran, and wheat bran, to name a few. Bacteria in the gut essentially break apart the fibrous portions of these foods to create short chains of fatty acid.
There are three major short-chain fatty acids produced by bacteria in the gut; acetate, propionate, and butyrate. Each performs its own action in the gut and overall system with far-reaching effects. While many bacteria in the gut have the capacity to produce SCFAs, a lack of proper substrates, such as dietary fibers, can lead to lower SCFA levels and open the door to potential health issues. Studies reveal lower levels of SCFAs in patients suffering from inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease.
Effects of SCFAs in the gut
Short-chain fatty acids are essential not only for intestinal energy sourcing but they have also demonstrated immune-modulating and anti-inflammatory actions in the gut. When produced, these SCFAs are almost entirely absorbed by the gut tissue, indicating their importance in gut health. They have been demonstrated to also play a role in intestinal permeability, promoting a healthy barrier in the gut.
Literature demonstrates the role of SCFAs in metabolic and gut health. Positive associations exist with the short-chain fatty acid acetate and appetite regulation. Other studies indicate the preventive role of butyrate in colon cancer. These small molecules have also demonstrated immune-modulating properties by affecting specific immune cells such as neutrophils, macrophages, and more.
Butyrate in our gut
Butyrate is a short-chain fatty acid in the spotlight right now. Of the three SCFAs, butyrate is present in the lowest concentration; however, its role in intestinal health cannot be overstated. Butyrate is a prime energy source for colon cells, and it promotes a healthy intestinal barrier by enhancing cellular junctions and the mucus layer of the gut. The anti-inflammatory nature of butyrate is shown in cell studies through its ability to block a potent pro-inflammatory factor known as nuclear factor kappa B. A small observational study also found that butyrate reduced intestinal inflammation in patients with the inflammatory bowel disease ulcerative colitis. And in some studies, the SCFA has been shown to block a key enzyme responsible for the growth of colorectal cancer.
While SCFAs seem to confer a host of benefits in the intestinal tract, some reports find negative associations with excessive amounts of SCFAs. This negative association is believed to be caused by an issue with absorbing the SCFAs produced in the gut. High amounts of these fatty acids can cause intestinal permeability, metabolic imbalance, and intestinal imbalance, also called dysbiosis.
Overall, SCFAs are prime movers in optimizing our intestinal health with far-reaching effects beyond the gut. Increasing fiber-rich foods through the consumption of whole foods, fruits, and vegetables, is a simple and powerful way to increase the production of these amazing molecules. As always, discuss with your doctor before increasing fiber content in your diet.
About the Author
Asia Muhammad, ND is a Doctor of Naturopathic Medicine and an expert in functional medicine and personalized health. She specializes in gastroenterology, mind-body medicine, and stress management and has received additional training in mind-body therapies. Learn more at asiamuhammad.com or follow Dr. Asia on Instagram.