Why Short-Chain Fatty Acids Are Key To Gut & Overall Health, Plus How To Get MorePosted: August 22, 2019 Filed under: Food and it's Impact on Our Health 1 Comment
August 15, 2019 — 9:18 AM
In fairy tales, Hansel and Gretel and Little Red Riding Hood have to outsmart some pretty creepy monsters. A journey into the forest means fending off werewolves and witches who are lurking around the corner. They enter at their own risk and learn to pack a silver bullet—a seemingly simple, magical solution to fending off the villains.
In the real world, we grapple with different—albeit equally terrifying—monsters: leaky gut, autoimmunity, heart disease, and cancer. And as a gastroenterologist, I’m not supposed to tell you there’s one seemingly simple, magical solution to our medical 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’d once been taught. Instead, prebiotic fiber—which boosts 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 have anti-inflammatory properties 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:
1. 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. coli and salmonella. The end result: more good gut microbes, more diversity, and fewer bad dudes—all of which means better overall health.
2. 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% of their energy. In fact, it actually repairs leaky gut by increasing the expression of tight junction proteins, and, according to a 2012 study, 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.
3. 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 production 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 found at the heart of inflammatory bowel diseases like Crohn’s and ulcerative colitis.
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 studies 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 apoptosis. 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 discovered 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.
I’m not against fiber. I eat some high-fiber vegetables, especially fermented, along with other cultured foods. But as I’m sure you know, SCFAs is a complex topic, as is the microbiome of which we know little. As aside note, acetate and butyrate are ketogenic, whereas propionate is glycogenic. SCFAs can come from other sources besides fiber. Butyrate, for example, is found in butter. The cow eats the fiber and makes the butyrate for us. So butyrate deficiency shouldn’t be a problem for anyone on a reasonably healthy diet, plant-based or animal-based.
I’m not as familiar with acetate, but apparently you can get it from apple cider vinegar, something I take on a daily basis. I assume that the microbes in the ACV produced the acetate and so bypasses the need of the microbes in your own gut to do the work. No fiber is required, at least not in the diet. Furthermore, one can get acetate from ketosis as well. Acetate/acetoacetate sometimes is what is measured for ketone levels. Some amino acids such as leucine and lysine can be converted into acetoacetate through fatty acid synthesis. Acetoacetate then is reduced to beta-hydroxybutyrate and the latter gets turned into acetone and acetate.
Propionate is a fascinating one. It is a food additive that the modern person is getting overdosed on and appears to be a causal factor behind such conditions as autism. Those on the autistic level tend to have high levels of the bacteria that produce propionate and tend to crave foods that are high in it. Rodents injected with propionate express autistic-like behaviors. And those on the autistic spectrum show decreased behavioral problems when propionate is removed from their diet or when an antibiotic kills off some of their microbiome.https://benjamindavidsteele.wordpress.com/2019/01/30/the-agricultural-mind/
No studies have been done on the microbiome of those on a carnivore diet or near-carnivore diet such as the Inuit. But it appears humans have multiple pathways to producing or obtaining SCFAs. The microbiome, in particular, is probably extremely adaptable to a wide variety of diets that were necessary during evolution. Paul Saladino has talked a lot about this kind of thing:https://hvmn.com/podcast/episode-124-dr-paul-saladino
“There are many bacteria which can metabolize fat, protein and animal-based collagen. That’s the thing I think that most people are missing. That our gut microbiome can shift. There’s a study where they put people on what I would consider to be a very poor version of a carnivorous diet and they compare it a plant-based diet. What they see is a divergence in the gut flora within a week. The animal-based eater, again, it’s not an ideal diet. The animal-based eaters had more bile acid tolerant organisms and more organisms to ferment fat and protein. They made isobutyrate and they made acetate and they made propionate as short chain fatty acids.
“The plant-based eaters made butyrate as a short chain fatty acid and had different colonic and small intestinal microflora. The investigators in that study jumped to the conclusion. Look, we know what’s going on with the gut because they have this organism. What’s worthy of biophilia or they don’t have this organism. They clearly have an unhealthy gut microbiome and I think that is an extrapolation. We do not know that. Clinically, nobody is assaying anything clinically in that study. They didn’t do inflammatory markers. They didn’t follow those people moving forward. It was almost like a setup. They were just trying to prove that these bile acid tolerant organisms would show up when they gave people a bunch of foods, which promote the formation of bile.”
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