SUPPLEMENTS Understanding glucosamine
Q:In “Exercise and Arthritis” (Consultants, EQUUS 464) a letter from a reader solicited advice for managing her arthritic horse; the letter writer stated that the horse in question was also prone to laminitis. The horse was already receiving an MSM/glucosamine supplement, and Roland Thaler, VMD, the consulting veterinarian who answered the question, also referenced glucosamine-containing supplements, among others, to help horses with arthritis.
Because this reader’s question
pertained to an older, laminitis-prone horse, it’s likely that he could be insulin resistant. I was under the impression that supplementation with glucosamine should be avoided since it could exacerbate the laminitis. Glucosamine is a sugar and has been used in laboratory settings and animal studies to induce insulin resistance to study the condition. It is my understanding that donkeys should not be supplemented with glucosamine under any circumstance.
As we all know, a laminitis flare-up can be career-ending, life-altering or worse. I wouldn’t know myself if I hadn’t lived it. L. Diane Stowe Heath, Massachusetts
A:Let me sincerely commend you for your concern about the welfare of horses. Preventing laminitis is a desire we all share. But I would like to address several points.
First, glucosamine is not a pure sugar, like glucose, fructose and others. It is an amino sugar, which is a sugar combined with a nitrogen compound called an amine, and it is manufactured in all of our bodies to sustain the processes of life. While the metabolic pathways of glucose and glucosamine are somewhat closely related, they are distinct.
Most studies have shown that glucosamine supplements do not affect glucose metabolism at the sustained daily dosages typically used by people. So, in general terms, glucosamine is deemed safe for human supplementation, even for people with diabetes. Additional studies on the effects of glucosamine on the metabolism in other mammal species have yielded the same conclu-