Butyrate and the Bowel – Part 2
Butyrate is something that has existed for millennia, unknown and unrecognized. You may ask why bother learning about it now, if we’re doing fine while blissfully ignorant of it. Well, the truth is, that’s the problem. We aren’t doing fine. Some of the symptoms and poor health conditions we suffer from and complain about are potentially related to this very important substance that’s birthed in the recesses of our gut.
Not just anyone can produce butyrate. Certain bacteria that thrive in the lower intestinal tract make butyrate from fiber and resistant starches, and when we consume these, they travel through our digestive tract intact until bacteria get a hold of them. They ferment these indigestible carbohydrates, and the byproduct is butyrate, a short-chain fatty acid. One of the roles of butyrate is to then serve as the major energy source for colon cells—and it has been estimated that short-chain fatty acids contribute 60 to 70 percent of the energy requirements of the colon.
Butyrate is not the only byproduct, or metabolite, of the bacteria. There are other short-chain fatty acids that are produced and absorbed in both the small and large intestines. Butyrate though, has received particular attention for its beneficial effects, even though it is the least abundant one produced. A healthy gut is characterized by a healthy, diverse population of microbes with sufficient supplies of butyrate.
There are a number of factors that can cause a decline in butyrate production. Age, infection, low-fiber diets, high-fat diets, and antibiotic use all can cause low butyrate levels in the gut. That just makes sense doesn’t it? Insufficient fiber in the diet doesn’t provide the “food” for certain bacteria to thrive and produce butyrate. Antibiotic hits or infection can lead to changes in the community of bacteria in our guts, lowering the population of the bacteria that produce butyrate or in some way disturbing their normal function. Whatever the cause, if this small, seemingly insignificant player in our gut’s ecology is not around like it used to be, we’ve got problems—potentially lots of problems.
Researchers have observed that individuals with colon cancer have a distinctively different composition of microbes in their gut than individuals of a healthy control population. Characteristic of the microbiome of individuals with colon cancer is the increase of potential pathogens and decrease in butyrate producers.1
For those of you who faithfully read these articles, you will know what we are talking about when we mention the term “leaky gut.” Butyrate has been “described as an intestinal barrier-strengthening agent” therefore counteracting leaky gut.2 One study discovered an interesting path butyrate takes to benefit us in this way: We may think that butyrate somehow strengthens the intestinal wall simply by its presence. But apparently it is a lot more complicated than that. Short-chain fatty acids such as butyrate “readily cross the gut-blood and blood-brain barrier and acts centrally to influence neuronal signaling.”3
Researchers found that butyrate improved leaky gut through its presence and effect on the central nervous system. Think about this: The bacteria in your gut produce something from breaking down fiber. That substance is absorbed into your body and is transported to the central nervous system. There it influences the communication of the nervous system which ultimately improves and strengthens gut permeability! That is wild!
Butyrate in the nervous system? Yeah! And it doesn’t just seek to benefit its hometown. Just as it’s possible to have a leaky gut, it’s possible to have a leaky blood-brain barrier. And the two are more related to each other than you may think.
Mice who were born and raised germ-free (meaning they were sterile mice, no bacteria inside of them) had a leaky blood-brain barrier. But amazingly, the researchers observed restoration of the blood-brain barrier when they were inoculated with short-chain fatty acid-producing bacteria. Another study was done with mice with traumatic brain injuries. They experience the same results from traumatic brain injuries as humans: brain edema, damage to brain cells and blood-brain barrier permeability. When these mice were supplemented with sodium butyrate, all of these symptoms improved. The researchers stated, “The protective effect of SB may be correlated with restoring the BBB following its impairment.”4
Butyrate is one of those friend-of-a-friend dynamics that has a whole lot more to do with your life and well-being than you probably realized. I’m hoping that butyrate is becoming increasingly interesting, because there’s more to come!
1. https://pubmed.ncbi.nlm.nih.gov/23733170/
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7277647/