Can high levels of fructans in the diet lead to laminitis concerns?

Hoof Nutrition Intelligence is a twice-a-month web segment that is designed to add to the education of footcare professionals when it comes to effectively feeding the hoof. The goal of this web-exclusive feature is to zero in on specific areas of hoof nutrition and avoid broad-based articles that simply look at the overall equine feeding situation.

Below you will find Part 1 of the latest question and answer installment that you can share with your footcare clients.

Q: Can high levels of fructans in the diet lead to laminitis concerns?

By Eleanor M. Kellon, VMD

A: While horses, ponies, donkeys and mules may develop laminitis on diets based on either hay or pasture, the cause isn’t fructan or hind gut acidosis. Instead, science shows laminitis is linked to high insulin levels in metabolic syndrome horses on a diet that is too high in sugar and starch.

The American Association of Equine Practitioners Laminitis Working Group did a 4-year study with the goal of identifying laminitis risks. Other than diet, equine metabolic syndrome (EMS) pattern obesity, pituitary pars intermedia dysfunction (PPID) and the use of corticosteroids within 30 days were identified as risks. All relate to EMS and elevated insulin levels.

A 2006 field study performed by a group from Virginia Polytechnic Institute, followed 106 mixed-breed ponies on pasture for a year. They found both prior laminitis and development of acute laminitis correlated well with indicators of insulin resistance. There was no increase of fructan in the pasture when laminitis cases appeared, no indication of diarrhea or hind gut upset.

In a 2016 study, Menzies-Gow, et al., followed 446 animals on pasture over 3 years. They found the most reliable indicator of risk of laminitis was basal insulin levels and that fructan does not increase insulin. There was no indication of the diarrhea or hind gut upset that accompany fructan overload.

A 2019 study by de Laat, et al., looked at 301 cases of naturally occurring laminitis and found EMS and/or PPID in 94% of these horses. Those that did not have elevated insulin at the time of testing may have been reflecting their current diet rather than their state at the time of acute laminitis. Again, no diarrhea or other indication of hind gut distress was reported.

There are many other studies and they all come back to insulin. Very large doses of pure fructan fed by stomach tube — a highly unnatural scenario — can experimentally cause laminitis by resulting in extreme hind gut acidity, damage to the intestinal lining and absorption of bacterial products in the same way gorging on grain can. This hind gut upset is accompanied by diarrhea, septicemia and fever. These horses are clearly sick, but none of that happens with naturally occurring laminitis.

Not only are there no documented cases of high fructan in pasture causing laminitis, the levels of fructan naturally found in a day’s worth of eating pasture grasses almost never come even close to the amount needed to cause laminitis.

Dr. Eleanor Kellon, a staff veterinary specialist for Uckele Health & Nutrition, has been an established authority in the field of equine nutrition for over 30 years. The owner of Equine Nutritional Solutions in Robesonia, Pa., she is a founding member and leader of the Equine Cushing’s and Insulin Resistance (ECIR) group, whose mission is to improve the welfare of horses with metabolic disorders via integration of research and real-life clinical experience. Prevention of laminitis is the group’s ultimate goal.

Click here to read part 2 of the Nov. 15, 2020 installment of Hoof Nutrition Intelligence: What are the concerns with over and under supplementation on hoof quality? Click here to read more installments of Hoof Nutrition Intelligence.