What Is The Cause Of EOTRH In Horses?

After the 2017 meeting of the American Association of Equine Practitioners (AAEP) featuring Dr Paddy Dixon, the world’s leading expert on dentistry in horses, the cause of EOTRH in horses is still unknown. But I have an idea that merits this blog.

Equine Odontoclastic Tooth Resorption and Hypercementosis has always been know as ugly teeth of old horses. There are several clues that I have put together with the final clue given by Dr Dixon at the meeting.

The upper canine has split from decay from EOTRH. Note the receding gum and enlarged bone underlying the incisors.

The first clue here is “old.” This disease is not seen in young horses.

The second clue is that it mostly affects the incisor teeth followed by the canines and rarely seen in the cheek teeth. In other words the disease appears mostly in the front of the mouth.

The third clue is that it is rarely seen in ponies and mini horses.

The forth clue is that there is no written discussion of this disease until recently. Maybe the last 30 years and before this there is no mention of it.

The fifth clue was given by Dr Early at this meeting when he said the word “hypercementosis” may not be accurate. The words cemental hypertrophy may be more accurate because the teeth are reacting to the disease in the bone in an effort to save the teeth. In other words the teeth are not the primary disease but a result of the underlying bone disease.

The smooth pink area at the end of this tooth is the reactive cementum as the tooth tries to save itself from the bone inflammation.

The final clue came from Dr Dixon when he said that he believed that EOTRH is an autoimmune disease. In other words the horse is turning its immune system against itself attacking the cells of the front of the mouth and killing them.

From the last 2 clues obtained from attending the AAEP meeting I now have all the pieces to put forward my hypothesis of the cause of EOTRH in horses. It is built upon my recent discovery of the world of plant lectins and the damage they cause to the lining of the gut wall in all animals. Most of the research has been done in humans on lectin effects while the horse world of research is just discovering the gut microbiota, microbiome, and the effects of anti-inflammatory drugs and antibiotics on these diverse bacteria. But in humans, the studies have gone to the root of the problem by determining the cause of the microbiome (gut bacteria) dysfunction.

Steven Gundry, MD is the leading expert on the effects of plant lectins on humans. In summary, these plant proteins are part of the plant’s defense mechanisms designed to discourage predators from eating them. Please pick up a copy of his book, “The Plant Paradox” to learn more about this.

An example of a lectin is gluten but there are thousands more such as the more devastating Wheat Germ Agglutinin (WGA). WGA is a lectin found in the covering of wheat (wheat bran, whole wheat, wheat middlings) which damages human bodies in 11 different ways. The primary effect of WGA is the mimicry of insulin which leads to insulin resistance (IR), obesity and type 2 diabetes. In 2012 a Nobel Prize was given to the discovery of cell hormone receptors being covered by lectins mimicking the hormones and disrupting their ability to do their jobs.

Should We Be Happy Feeding Byproducts To Our Horses?

Almost every commercial horse feed and horse treat has as its main ingredient “wheat middlings” which is the stripped away byproduct of wheat when the bran is removed for the production of white flour. Thousands of years ago humans found that the whole wheat grain made us ill and soon learned that removing the outer layer of wheat was healthier. Asians also found that removing the outer brown layer of rice was healthier. Italians were introduced to tomatoes only 500 years ago became ill from them until they removed the skin and seeds. Lectins are concentrated in the skin of all plants and their seeds to make predators ill and thus make animals stop eating them.

The gut of all animals starts at our lips where our skin meets our mucosa. Lectins that are swallowed escape the effects of stomach acids and then, in the small and large intestines, physically penetrate the space between the tight junctions between the cells that line our gut (enterocytes). It is only 1 cell layer thick so this breech between the enterocyte cells creates an inflammatory response just like a splinter of wood penetrating our skin. The result of this penetration of lectins can be seen under the microscope and is commonly called “leaking gut syndrome.”

In humans, Dr Gundry has determined that lectins are behind all autoimmune diseases including lupus, rheumatoid arthritis, psoriasis and Hashimoto’s Thyroiditis among others. He has treated over 10,000 patients with dozens of diseases recording blood inflammatory markers and has resolved these diseases by removing the causative agents. In other words, his approach to disease is not to treat it but to remove the cause followed by, what Hippocrates noticed 2000 years ago, the body’s ability to heal itself once the cause is removed.

What does this have to do with EOTRH in horses?

What if a lectin such as WGA found in the grains we feed horses, especially wheat middlings, is damaging the endothelium of the mouth and creating an autoimmune response in the underlying bone? Before we jump to a conclusion, let’s look at our own defense mechanisms against lectins.

Sugar molecules attach to lectins and make them unavailable to cause gut damage. These sugars are called mucopolysaccharides and are found in the saliva and the mucous lining of the entire gastrointestinal tract. Therefore saliva is our first line of defense against plant lectins. The second line of defense is stomach acid and the third line are the specific bacteria that digest lectins such as gluten.

If saliva is the first line of defense, what if the saliva is either diminished or restricted to the back of the mouth? If this happens could it be possible that in some horses that bite into grain that the lectin damage to the gum endothelium becomes damaged? A retrospective study needs to be done that determines if horses with EOTRH have also been fed grain. Could this be the reason that ponies and mini horses who are not fed grain don’t get this disease? What about the horses fed grain that don’t get EOTRH? Maybe these horses have better saliva distribution or better immune systems. Maybe having fresh water during grain feeding is washing away the protective saliva (In Tom Brady’s new book he advocates NOT drinking water with meals for this reason).

Proving the theory that lectins from grain causes EOTRH is needing data from good research. However there needs to be a treatment for those with the disease now. There is anecdotal evidence that applying a mushroom extract to the gums may alleviate or lessen the effects of EOTRH in horses. This may be possible because it has been shown in humans that mushrooms have an anti-lectin effect. In addition, my colleague in Sao Paulo, Brazil told me that he has seen improvement in horses whose incisors are brushed with honey. While honey is bacteriostatic, it may also be the sugars that are binding to the lectins preventing further damage.


There is mounting evidence from my clients taking the no grain challenge that horses who no longer eat any grains see improvement in behavior, weight management (thin horses become fat and fat horses become thin), sweating, conditioning and some skin and hoof problems. It has been my belief that grains cause inflammation in the horse’s gut and upset the natural microbiome (gut bacteria) which in turn cause illness and chronic protein deficiency. I now further believe that there may be other diseases in horses with an autoimmune component that may be directly caused by lectin damage and hormone mimicry by circulating lectins.

In the world of Parkinson research it is becoming clear that lectins are disrupting the gut microbiome and that elimination of lectins and the reestablishment of the normal gut microbiome quiets and even reverses the disease. Research in dementia, Alzheimer’s and other cognitive disorders in humans are now finding that lectins are actually traveling up the vagus nerve from the gut into the brain creating inflammation. The brain’s response to this starts with “foggy brain” and leads to more serious brain disease. Is it also possible that lectins may also be causing damage to the neurotransmitter dopamine or it’s receptors which is the root cause of Cushing’s disease in horses? What about insulin resistance caused by WGA or metabolic syndrome? All of these diseases are relatively new and could be associated with the modern husbandry practice of feeding grain.

One more interesting note. At the AAEP meeting there was a lot of discussion around the discovery of dental carries (cavities) causing decay which leads to the fracturing of cheek teeth. No one knows the cause of this but again, it is a relatively recent phenomenon in horses as there is little mention of cheek tooth fractures in older text books. In 1932 a study was done in children who were developing a high number of cavities. Researchers documented their observations and then removed oatmeal from their diet (a standard back then) and added vitamin D and Cod liver oil. The tooth decay went into remission and actually was eliminated within 6 months. Could tooth decay also be associated with lectins?

There is evidence that all grains (wheat, corn, oats, barley, rye, quinoa, and others) is literally killing us. Grains are only less than 10,000 years old in our diets, 4000 years old in civilizations (Egypt and the middle east), 2000 years old in modern civilization and maybe 50 years old in our horse’s diets. Our gut microbes are overwhelmed and the diseases and obesity that plague us and our horses are not rising because of better detection, but are simply rising because of the survival changes we have made as a culture in beings that are well over 100,000 years old and many over 1 million years old. It’s worth thinking about, isn’t it?

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