Stress, frequent diet changes and other factors can cause Leaky Gut Syndrome. The only way to address it is through nutrition. • Photo by Molly Montag.

Leaky Gut Syndrome: A Hidden Danger for the Horse

There are many things in this world we do not know about that will not necessarily hurt us.  I am not saying that ignorance is bliss, but it does cut down on our cumulative stress level. There are some things, though, that we live with every day truly having no knowledge of that can, and will hurt us, regardless of our ignorance.  To try and relate this to our horses I will use a prime example. One of the most important equine conditions that you have may have never heard of is called Leaky Gut Syndrome (LGS).  

It is aptly labeled a syndrome because it is a grouping of symptoms that occur together and characterize a particular abnormality or condition, whereas a disease typically manifests itself by distinguishing signs and symptoms. For example, kidney disease is identified by specific bloodwork abnormalities of particular enzymes and/or histologic changes seen on biopsy of the tissue. Leaky Gut Syndrome is a collection of nonspecific symptoms that can be attributed to an unrecognized underlying condition. A truly definitive diagnosis of LGS is more difficult as there is no novel test to pinpoint it as the lone offender. I like to tell people that in situations like this you have to back into the diagnosis.  In other words, we often use response to treatment as our confirmation of diagnosis. 

From a symptom standpoint, you can see a wide variety that present across a plethora of common equine disorders. Generalized weight loss, poor appetite, low grade or recurrent colic, and increased fecal water or a loose stool are commonplace.Those symptoms make sense, but when you add in other body systems you see things like allergic dermatitis, joint pain, and an overall weakened immune system leading to recurrent infections. Again, you can match up that horse with at least 5-7 other well-known and commonly treated illnesses. So, to better understand and sift the equine protozoal myelitis, gastric ulcer, and otherwise over-worked horses from the LGS cases we need to understand the pathology.

A quick review of the anatomy of the gut is in order.  If you think about it, the inside of the gut is really still the outside world. In essence, it is a hollow tube extending from one end of the horse to the other. Things come in and go out, and only a select few things are incorporated into our horses. This is the key to LGS. The natural barrier of the gut, which normally does the work of letting good things in and keeping bad things out, fails to some degree. Starting from the inside of the gut, horses have a mucus barrier as a first line of defense. This mucus barrier lays atop small, hair-like projections called intestinal villi which are attached to the actual intestinal epithelial cells. Next, you have the tight junctions between the epithelial cells that hold the individual cells into a tight line ultimately forming tissue, and thus the length of gut. When this tissue operates as intended the world is great. You have heard it said that up to 80 percent of your immune system is in your gut? If you do not believe that, wait until your gut defense fails and things from the outside make their way inside. This is the premise of LGS. 

The negative things that accumulate over time in our horses’ lives can break this very important barrier down. I mention stress first for a reason, because it is the main culprit in a generalized weakened immune system. Other things such as frequent diet changes rank high on the list. These may be unintentional and beyond our control, or well-planned out as seasonal availability of forages changes. Some beautiful hay can have mycotoxins. Your horse may desperately need antibiotics, or other intestinally-absorbed medications, but they can have direct negative effects on the population of good intestinal microflora. The list of detrimental ways we can impact the health of our horse’s gut is long, and we cannot take ourselves out of the equation with regard to how we handle them. 

So, stressful events, feed changes, medications, and naturally occurring infections chip away at the cellular integrity of the gut at the biochemical, microscopic level. Eventually, the barrier is breached. Most commonly in small, but multiple areas. When this happens, what was once a tightly regulated barrier with permeability only to the beneficial things has become much more porous to everything. Like a leaky sieve, it slows unintended toxins, microorganisms, and chemical mediators of inflammation to enter the body.  Quickly recognized as foreign invaders these pathogens signal the body to respond. As such, the cycle of increased gut permeability, inflammation and tissue failure is begun. Hence, the name Leaky Gut Syndrome.  Leaks will remain and increase until identified and appropriately treated.  

Fractures are repaired by bone plates and screws. Infections are killed off by antimicrobials drugs. Suspensory tears can heal through platelet-rich plasma, but LGS must be addressed through proper nutrition. The key to healing these leaks lies in providing the nutritional building blocks that repair and restore proper gut function. Simply put, we must do something to promote intestinal barrier strength, support gut immune function, and strengthen the natural intestinal barriers that have been weakened. The supplementation of specific amino acids improves intestinal barrier function. Free fatty acids, notably butyric acid or butyrate, are integral to proper immunologic operation of the intestinal mucosa and the tight cellular junction. All of these can be added to the diet with success, but without the aid of pre- and probiotics we will not see complete resolution of LGS.  In previous articles I have discussed the necessity of these beneficial microbial products across a wide range of equine applications. Here we see the true benefit of supporting the gut with good bacterial and yeast cultures that are proven to combat and offset the pathogenic byproducts of bad bacterial overgrowth that is a predictable outcome of the stress, diet and management induced gut bomb we all create within our horses.  

On an almost daily basis I see horse with these symptoms and talk to horse owners who feel helpless to aid their horses. For most of them they have tried various home remedies and concoctions they have heard from friends, so by the time it gets to me they want answers, not suggestions. My best advice is to reach for a product that is science based with published research to prove what they say will happen. Repeatedly. LGS may be a less than household name, but I promise you it is not an unsuspecting enemy of the horse. For years as we have gone about our lives there have been some very smart people researching and identifying the nutritional keys to healing horse’s guts. Follow the science every time. Your horse will thank you and work better to prove it.     

Presented by Kemin