Why Short-Chain Fatty Acids Are Key To Gut & Overall Health, Plus How To Get More
As a gastroenterologist, I'm not supposed to tell you there's one seemingly simple, magical solution to our gut issues. I even flat-out say to my patients, "There's no silver bullet." But let me tell you a secret—I actually think there's something that comes close.
Curious about this real-life sprinkle of fairy dust? They're called short-chain fatty acids (SCFAs), and I'm sharing the details on how they can shift your health for good and how to get more of them.
Why should you care about short-chain fatty acids?
Let's start with the basics. SCFAs are produced when bacteria—the good kind—ferment fiber in the gut, thereby providing your body with energy, keeping your metabolism humming, and even thwarting a wide range of digestive disorders.*
There are three main types of SCFAs: butyrate, acetate, and propionate. If you haven't heard of them, that's in large part because we've been ignoring fiber like it's the nerdy kid from high school. But that's all starting to change.
You see, fiber isn't just "in one end and out the other" as we were once taught. Instead, prebiotic fiber—which supports the healthy bacteria that are already living in your gut—reaches the colon and sends our probiotic bacteria into an absolute feeding frenzy. Jonesin' for their favorite food, probiotics go to town, and what results is postbiotic short-chain fatty acids.
You've heard of prebiotics and probiotics, but did you realize that the entire point of these is to make postbiotics, or SCFAs? These underrated byproducts of fiber fermentation have been shown to support a healthy inflammatory response throughout the body and loads of other health benefits in the gut and beyond.
What are the health benefits of SCFAs?
Back to my original point: SCFAs could be the silver bullet we've been looking for. Let me break the benefits down:
Your good gut microbes thrive on SCFA-producing fiber.
Studies have shown that fiber consumption increases the growth of healthy bacteria species such as lactobacilli, bifidobacteria, and prevotella. A January 2019 study showed that fiber also increases the diversity of species within the gut. Not to mention, the SCFAs produced by the fermentation of fiber in the colon suppress the growth of bad bugs like E. coli1 and salmonella2. The end result: more good gut microbes, more diversity, and fewer bad dudes—all of which means better overall health.
SCFAs heal the colon wall and correct leaky gut.
Butyrate—remember, that's one of the three types of SCFAs—is the main source of energy for our colon cells, providing up to 70%3 of their energy. In fact, it actually helps manage leaky gut by increasing the expression of tight junction proteins, and, according to a 2012 study4, butyrate has been shown to decrease bacterial endotoxin release into the bloodstream. If you're a nerd like me, then you know that I just described the solution for the gut dysbiosis—a microbial imbalance within the gut that can drive a variety of health issues from IBS to rheumatoid arthritis to type 2 diabetes.
SCFAs help regulate the immune system.
Short-chain fatty acids have been shown to inhibit three of the most powerful inflammatory signals in the body, NF-κΒ, IFN-gamma, and TNF-α. They also play a role in regulatory T-cell production5 and function for the entire body, which is kind of a big deal in terms of keeping your immunity on track. So not only do SCFAs correct dysbiosis and heal leaky gut, they also create a powerful link between the microbiome and immune system that serves to make the immune system work properly. This explains why a loss of bacterial diversity and inadequate supply of the SCFA butyrate have been found6 at the heart of inflammatory bowel diseases like Crohn's and ulcerative colitis.
SCFAs are cancer crusaders.
SCFAs actually have a direct anti-tumor effect thanks to their ability to regulate gene expression through enzymes known as histone deacetylases, or HDACs. One of the necessary steps for cancer development is unchecked cell multiplication and growth. There are multiple studies7 showing that—through their activity on HDACs—SCFAs are able to inhibit cellular proliferation. When you have dangerous cells, it's not enough to just slow down their growth. You need to stop them in their tracks, and the way this is done is by causing apoptosis, or programmed cell death. SCFAs have the ability to destroy cancer directly by inducing apoptosis8. If that's not a magic spell, then I don't know what is.
So how do you get more SCFAs?
You may be thinking, "This sounds great—where's the supplement?" The problem is that most butyrate supplements would be absorbed almost immediately in the small intestine and never make it to the colon (which is where it needs to end up). Plus, these SCFAs need to be properly balanced, which is exactly what happens when you let their trillions of bacterial friends do their job in the colon.
Instead, the best way to get the health benefits of SCFAs is through the consumption of dietary fiber found in fruits, vegetables, whole grains, seeds, and nuts. You can even try throwing it all into a gut-friendly smoothie. And for bonus points, sneak in some exercise, which we've recently discovered9 can help your body generate more SCFAs as well.
Bottom line: SCFAs are health-promoting powerhouses.
I could keep bragging about how SCFAs may help reverse diabetes, lower cholesterol, and protect us from heart disease and stroke. Or that SCFAs cross the blood-brain barrier, improving learning and memory, and may even protect us from Parkinson's and Alzheimer's diseases. That's because this food molecule is not a flashy trend—SCFAs are a real game-changer with the potential to legitimately transform the health of those who pursue it. But there's no magic pill, so keep loading up on fiber-rich foods and moving your body to harness their power.
Dr. Will Bulsiewicz, M.D., MSCI is a gastroenterologist and internationally recognized gut health expert who wants to help you tap into the incredible healing power that lives inside you—your gut microbiota. His medical training involved 16 years at America's elite institutions. He completed a bachelor’s degree from Vanderbilt University, a medical degree from Georgetown University, and a master's in clinical investigation from Northwestern University. Bulsiewicz was also the chief medical resident at Northwestern and the chief gastroenterology fellow at UNC, and received the highest award given by both his residency and fellowship. He also completed an epidemiology fellowship at UNC's prestigious Gillings School of Global Public Health.