Diabetes mellitus

Diabetes mellitus… otherwise known as just plain “Diabetes”, is every bit as sneaky and nasty a disease in dogs and cats as it is in people. Diabetes is created when cells in the pancreas (called Islets of Langerhans) no longer produce insulin. Insulin is required by the cells of your body as the transport mechanism for bringing glucose (energy) into the cells from the blood. Think of it as UPS or Purolator for energy. Without glucose (otherwise known as blood sugar) your cells have to burn alternative energy sources that create waste products (ketones) that make you sick and slowly cause your body to break down. Ever since Banting and Best (Canadian researchers!) discovered insulin and determined how it works, diabetes has ceased to be the more immediate threat that it was only a few decades ago. Regrettably it is still a difficult disease to completely control and as time passes the people and animals who suffer from this disease still experience serious and often life-threatening complications from diabetes.

Diabetes in dogs is virtually identical to insulin-dependent diabetes in humans. Dogs were actually the animal model that Banting and Best used in their development of insulin. The disease tends to strike in middle age and the most common symptoms are; a ravenous appetite, high water consumption (as well as frequent need to urinate of course) and rapid weight loss. A urinalysis and some bloodwork are all that are required to diagnose the condition.

Controlling diabetes in dogs is very much like controlling the insulin-dependent form in humans. We determine an appropriate dose of insulin for them, get them on a regular schedule (this is key!) and put them on complex carbohydrate diets much like they do with human diabetics. Like humans, the dogs will spend the rest of their lives requiring regular injections of insulin to remain healthy. Like most humans this dose of insulin doesn’t tend to vary much and we can monitor it fairly easily with regular rechecks or even at-home testing.

Cats, however, as usual, are an entirely different critter when it comes to diabetes. Initially diabetes in cats is often caused by an over-reaction of their immune system that leads to either partial destruction of their Islet cells or the creation of antibodies against their own insulin. This causes cats to have all of the symptoms of diabetes, but they have a tendency to relapse into a non-diabetic state periodically until the destruction of the Islet cells is complete and they become true diabetics. During this time they require insulin like dogs and people, but we have to monitor them very closely for the symptoms of insulin-overdose. These symptoms arise as they continue to get insulin and their own insulin production “comes back online” as their immune system stops destroying it. As you can imagine this makes diabetic cats a great deal more complicated to maintain than diabetic dogs.

To make things even worse, cats are carnivores, unlike humans and dogs. Up until as recently as about 15 years ago we still tried to put cats on complex carbohydrate diets to maintain them just as we did with people and dogs. However we often had a great deal of difficulty controlling our feline patients. Quite accidentally, through food research in an unrelated area, someone discovered that cats put on a high-protein diet who happened to be diabetic suddenly became much easier to control. Their blood glucose levels fell and the condition became manageable on much lower doses of insulin. At this point some bright person had a “eureka” moment… cats are not omnivores like dogs and people… they are carnivores. Omnivores create energy and blood sugar by breaking down carbohydrates from their food and feeding that energy into their cells. Carnivores on the other hand create energy by breaking down protein sources, with much less emphasis on the breakdown of carbohydrates. This discovery revolutionized the treatment of diabetes in cats. Now all cats are required to switch to high-protein, low-carbohydrate diets when we start to attempt to control their diabetes. This works particularly well when the diet is in the canned form as opposed to the dry form.

So, like in humans, diabetes is a disease condition that we can control, not cure. Like many humans, the disease strikes a bit later in life in dogs and cats and we need to use insulin to control it. The most important factor in the lives of these animals (after insulin of course) is “regularity”. They require their insulin doses at very regular intervals and they need to be fed at very regular intervals. This regularity allows their bodies to adapt to the use of injected insulin for the processing and transport of energy within their bodies. On appropriate doses and with regular monitoring diabetic dogs and cats can life very long healthy lives, much like their human counterparts.