In my last post I discussed the differences between pre-, pro-, and post-biotics.  They all have their part to contribute, but the take home message is that diversity and population of the gut microbiome is essential for optimal health.  In this post I want to get a little deeper into the Short Chain Fatty Acids (SCFAs), a type of post-biotic, and how they can impact the whole body. I want to focus on just a few of the more common and important conditions here but just know that the list is much longer than what I can cover in this short article.  

Local Gut Health

I have described before that SCFAs start benefiting us by helping to feed their neighbors. Healthy gut bacteria produce SCFAs for us and for themselves.  The gut microbiome tends to work as a thriving commune if you allow it to do so. The positive health of one organism will directly benefit the health of a neighboring microorganism by providing SCFAs to each other for the greater good.  This is called “cross-feeding.” (Perhaps we should learn a few things from our microorganism friends! Promoting success for one usually promotes success for all. But that’s another article.) Aside from that, SCFAs also feed our gut cells directly.  As a Functional Medicine practitioner I see my fair share of “Leaky Gut” conditions and the associated food sensitivities. Believe me when I tell you that these things are becoming much more common. We just aren’t tolerating the same foods we once did as a population.  A decline in a healthy gut microbiome is largely to blame. So by providing higher levels of SCFAs we can stimulate the gut cells to thrive while at the same time promoting a healthier microbiome through cross-feeding. Studies have shown that SCFAs act as cellular messengers in the gut cells to promote the creation of the barrier proteins responsible for filtering out offensive compounds.  Once these barriers break down, a person will have a “Leaky Gut” and anything they eat most often can soon become a problem. We must work at rebuilding the gut barrier to avoid the thousands of diseases and medical complications that can arise from a loss of a gut barrier. The bottom line here is if things are getting through that shouldn’t be, inflammation is the result which can lead to disease.  

Immune Reactions

Our gut is a major interface between the outside world (things like our food and things that are riding on or in our food), and the inside of our bodies (our blood stream).  That is why a healthy gut barrier system is so important. But aside from the barrier itself, we have a large amount of immune system cells in our digestive system. These cells are largely responsible for triggering (or not) immune responses to anything we encounter.  So if these cells are constantly being triggered they are sending signals to the rest of the immune system that they should trigger, too. I often get asked why so many kids these days are allergic to everything. Well, this is one reason. They have unhealthy guts! Once SCFA levels are optimized, the immune cells in the gut have a chance to relax.  They then send signals to the immune system at large to relax as well. Think of the immune cells in the gut as a general in charge of an army. If the general is touchy, nervous, or even vengeful you can be sure that battles will be fought. The idea is to not let the generals get touchy in the first place! That is one thing SCFAs can do directly.  

Another thing that I tend to see a lot these days is a person who comes in asking for some food sensitivity testing because they feel terrible no matter what they eat.  We run a panel of say 90 foods and they are reactive to 75% of them! This is a loss of tolerance to food and is a shortcut to larger medical concerns. Every bite of food becomes inflammatory and a trigger for immune activity.  Working with the immune system of the digestive tract by providing SCFAs can go a long way to calming down the system and allowing for better tolerance of foods.

Autoimmune Disease

Similarly to the overzealous immune response that we see in food sensitivity or allergy, the immune system can also begin attacking parts of our own bodies!  This is autoimmunity and I have written about it a lot over the years. One of the hallmark reasons that an immune system begins attacking self-tissues is that there is a loss of immune regulation by a type of immune system cell called Regulatory T-Cells.  These cells help the immune system be much more careful about what they attack. SCFAs have been shown to shift the immune system production of T-Helper 1 & T-Helper-17 Cells (inflammatory and destructive activities) into Regulatory T-Cells (Balancing and moderating activities).  So in an autoimmune disease it is important to help the body regain control of the immune response so that it no longer tries to destroy its own body! SCFAs have shown to do just that. This becomes particularly important when dealing with autoimmune diseases like Multiple Sclerosis for example where a person is destroying their own nervous system.  

Obesity

Lastly, I want to address another major concern people have regarding their weight.  This topic can of course involve a great many factors which is why it can be so difficult to manage.  But there is a link between an unhealthy microbiome and obesity. SCFAs have the ability to help regulate thermogenesis (the production of body heat through the burning of calories), blood sugar control, appetite control and weight gain.  Things like appetite are complicated as well but there is a known link here between the status of the microbiome and appetite! This link directly involves SCFAs. So perhaps adding in some SCFA support in a weight loss effort might just benefit the end goal.  

Conclusion

I want to reiterate what I said in my previous post - for a person to have a healthy gut microbiome they must start with a robust and diverse plant-based diet.  Add some probiotics and some SCFA supplements and now you have something that can impact the physiology at large. Taking pills alone might help in the short term but if you really want benefits to stick you need to start with what you eat.  Food is our primary medicine so eat well!