IR horses

It might seem counterintuitive to add another component to an insulin-resistant (IR) horse’s diet. After all, the goal is to keep these horses’ insulin responses low, and lowered responses come from small meals and reduced sugar and starch intake from hays and hard feeds. But one German research team said one supplement is showing promise in getting those sugars out of horses’ systems faster—at least in healthy horses.

The supplement? A prebiotic known as Jerusalem artichoke meal.

“The results of our study on nonobese healthy mares showed a tendency toward better glucose clearance after feeding a low dosage of Jerusalem artichoke meal,” said Maren Glatter, PhD, of Martin Luther University Halle-Wittenberg’s Institute of Agricultural and Nutritional Sciences Animal Nutrition Group, in Halle/Saale.

While this might sound like exciting news, it’s too soon to start filling our IR horses with Jerusalem artichokes. The researchers said they’re still not sure whether these positive findings will transfer to horses with insulin issues.

“On the contrary, more investigations have to be carried out to determine which other factors influence the effect of prebiotics to horses, such as body weight, health status, physical condition, or even breed,” Glatter said.

Even so, the study does open the door for further research that might lead to an effective and safe way to help manage IR horses, she said.

In their study, Glatter and her fellow researchers fed six Warmblood mares two supplements—Jerusalem artichoke meal (a commercial product fed at 0.15 grams per kilogram of body weight) or a control meal (ground maize cob without grains)—over two three-week periods. All the mares received one supplement twice a day before meals for one three-week period and the other supplement twice a day before meals for the second three-week period.

They found no differences in the mares’ initial bodily responses to the glucose and insulin, Glatter said. However, the mares cleared out the glucose and insulin from their systems faster when they’d had the Jerusalem artichoke meal compared to the control meal. In fact, glucose and insulin levels declined more rapidly for the first four hours after feeding and stayed lower compared to when the mares had the control.

A prebiotic essentially feeds healthy microorganisms, such as yeast and good bacteria, in the digestive system. Jerusalem artichoke (Helianthus tuberosus, also known as sunroot, sunchoke, earth apple, and topinambour) isn’t an artichoke at all. Rather, it’s a kind of sunflower that grows in eastern North America that contains inulin-type fructans, which are used to manage insulin responses in humans. It might eventually prove to help IR horses, as well.

The researchers said a growing interest in nutritional supplements for horses has gotten ahead of research on their safety and efficacy, which could have negative effects on equine health. That’s why studies like this one are critical.

“On the market, there are several products for horses containing prebiotic active substances which suggest a health-promoting effect,” Glatter said. “However, only a few scientific studies have investigated the impact of this prebiotics on horse health. So, we recommend a careful feeding of these products because a contrary effect might not be excluded.”

Specifically, more is not necessarily better. “A remarkable percentage of these substances seems to be already fermented in the stomach, which might be detrimental for the stomach’s health (as she had already noted in a 2016 study) and also reduces its impact on the intestine,” she said.

The study, “Glycaemic and insulinaemic responses of adult healthy warm-blooded mares following feeding with Jerusalem artichoke meal,” was published in the Journal of Animal Physiology and Animal Nutrition.