Psyllium for Glucose and Insulin Control

Veterinarians often recommend psyllium for use as a laxative, specifically for clearing sand out of horses' intestines to minimize the chances of sand colic. But new research indicates there might be another use for the phytogenic (plant-based) supplement: the control of blood glucose and insulin concentrations.

Research performed in humans indicated that oral psyllium supplementation reduced blood sugar and insulin response after eating, but psyllium's effects on horses' blood glucose and insulin levels had not previously been examined. Shannon John J. Moreaux, DVM, assistant professor of equine science at Montana State University, and a team of researchers set out to determine whether psyllium would have the same effect on horses.

Both insulin and glucose play a role in equine insulin resistance (IR), a hormonal disorder that most commonly occurs in horses with equine metabolic syndrome and in those with equine Cushing's disease (pituitary pars intermedia dysfunction, PPID). Insulin's main function is to control blood sugar (glucose) levels by signaling fat, muscle, and liver cells to take up glucose (a simple sugar resulting from the digestion of food) from the blood and store it as glycogen (stored complex carbohydrates--essentially, a main source of fuel for the horse). Insulin resistance is a reduction in a horse's sensitivity to insulin that makes it harder for the fat, muscle, and liver cells to transport the glucose out of the bloodstream and store it as glycogen.

The team employed 16 stock horses (eight mares and eight geldings) that were 7 to 16 years old. The horses were healthy with no known medical or soundness conditions. All of the horses were fed a diet of mixed grass hay and a commercial whole grain feed twice daily.

Moreaux and colleagues separated the horses into four groups, each containing two mares and two geldings. Each group received one of the following supplement courses:

  • 90 g of psyllium per day;
  • 180 g of psyllium per day;
  • 270 g of psyllium per day; or
  • An isocaloric control (an untreated control group).

The psyllium pellets were added to the horses' daily grain rations for 60 days.

On Day 60 the researchers fasted the horses overnight and drew a blood sample before feeding the next morning's rations. After they fed the animals their normal morning feed, team drew blood samples every 30 minutes for six hours to monitor the horses' glucose and insulin levels.

Upon reviewing their results, the team found that the horses that received psyllium for 60 days had lower average blood glucose levels after feeding and lower average peak glucose levels. Additionally, the psyllium-fed horses had lower average post-feeding insulin levels and lower average insulin concentrations than the nontreated control horses. Of the horses that received psyllium, the dosage made only a minimal difference on the levels of glucose and insulin present in their bodies.

"Psyllium could be especially beneficial to obese, insulin-resistant horses, or horses that are predisposed to developing laminitis because of metabolic syndrome," Moreaux said in the study. "It is commercially marketed and readily available to horse owners, and when fed daily, may help to maintain lower postprandial (post-feeding) blood glucose and insulin levels."

The researchers noted that additional trials that encompass "larger populations of horses, obese horses, and horses exposed to pasture forages" would be beneficial to further the understanding of the supplement's effects.

The study, "Psyllium Lowers Blood Glucose and Insulin Concentrations in Horses," was published in the March 2011 Journal of Equine Veterinary Science. The abstract is available online.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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