Possibility of Gluten Sensitivity in Horses Examined

While the exact cause of inflammatory small bowel disease (ISBD) in horses remains unknown, a group of Dutch researchers suspect that gluten intolerance could be a contributing factor of the disease. They recently tested their hypothesis and found that gluten sensitivity in horses is a possibility.

Gluten is a protein composite found in foods processed from wheat and related grains. Inflammatory small bowel disease is a condition that results in malabsorption and maldigestion of feed. Common clinical signs include poor body condition, weight loss or failure to gain weight; decreased appetite, increased gastrointestinal motility, a history of mild recurrent colic, and occasionally, diarrhea.

"Concentrates designated for use in sport horses ... are containing an increased amount of (gluten-rich) wheat ... as we learned from representatives of the feed industry," noted Han Van der Kolk, PhD, DVM, a faculty member in the Department of Equine Sciences at Utrecht University's Faculty of Veterinary Medicine, located in The Netherlands.

In their study, the researchers compared blood work from three groups of horses:

  • Twelve dressage horses referred to the University's Equine Clinic, all of which showed clinical signs of ISBD;
  • Twenty-two university-owned control horses fed a gluten-rich diet; and
  • Twenty-five Shetland ponies living on a nature reserve in Zeeland, The Netherlands, that ate a low gluten (or gluten-free) diet of natural forages.

All horses were tested for the presence of immunoglobin A (IgA), one of the most prevalent antibodies produced by the body, to rule out an antibody deficiency. Blood analyses also tested for antibodies against transglutaminase 2 (TG2), gliadin, and endomysium (EMA). The team noted that all the antibodies they evaluated are "known to be important in the diagnosis of human coeliac disease," which is caused by a reaction to a specific gluten protein and necessitates a gluten-free diet.

Key findings from the study include:

  • None of the horses showed IgA deficiency;
  • ISBD horses had significantly increased IgA antibodies against TG2 compared to gluten-poor ponies, but not to gluten-rich controls;
  • Antibodies against EMA tended to be higher in ISBD horses than in gluten-rich controls; and
  • Researchers placed one ISBD horse with high gluten intolerance-associated antibodies on a gluten-free diet. After six months his antibody levels had decreased and his small bowel appearance and performance had normalized, the team relayed.

"Our findings suggest the presence of gluten-sensitive enteropathy (GSE) in at least some horses suffering from ISBD," the team concluded. The researchers added that further research into equine GSE is warranted.

The study, "Gluten-dependent antibodies in horses with inflammatory small bowel disease (ISBD)," was published in Veterinary Quarterly in April 2012. The abstract is available online.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.