Diabetes mellitus, which is commonly referred to just as “diabetes” in both people and animals, is a condition where the animal’s blood sugar, or blood glucose, is high due to lack of production of insulin or a poor response to insulin. Insulin is a hormone that allows the pet to absorb glucose from the blood into their cells and utilize it. Insulin is produced in the pancreas.

A pet with newly diagnosed or poorly regulated diabetes mellitus will often show signs such as frequent urination, increased water intake, increased appetite, weight loss, and lethargy. Diagnosis is made with lab work and is usually based on the presence of high blood glucose concentration, consistent signs, and high levels of glucose in the urine. Sometimes, there will also be ketones in the urine, which are produced in the body when the pet is having significant trouble accessing glucose from the food.

Despite both species developing diabetes, the disease is quite different between dogs and cats. Dogs have “Type 1” diabetes mellitus, which is also called insulin dependent diabetes, while cats usually have “Type 2” diabetes mellitus, which is often called non-insulin dependent diabetes. Because the disease is different between dogs and cats, medical and nutritional management strategies differ between the two species.

Diabetes in Dogs

Dogs get insulin dependent diabetes mellitus, which is similar to Type 1 diabetes in people. It is usually caused by damage to the cells in the pancreas that produce insulin. It can be autoimmune, where the body attacks the cells that produce insulin, or associated with pancreatitis, which is inflammation of the pancreas.

All dogs with diabetes mellitus require insulin therapy as part of their treatment. Insulin is given twice daily by injection. The injections should be given 12 hours apart. Owners of diabetic dogs have to learn how to give their dogs injections, which can be difficult, and should learn proper insulin handling, like not shaking the insulin and keeping it refrigerated between doses. Insulin must be given with food, and pet owners should go to a veterinary emergency center if they give their pet insulin and then their pet does not eat more than half of their meal. Giving insulin without food can cause hypoglycemia. If you have a diabetic dog who is picky and doesn’t routinely eat well, a board certified veterinary nutritionist can help find a nutritional plan that works for your dog.

The most important nutritional consideration for dogs with diabetes is a feeding schedule. Owners of diabetic dogs should maintain a consistent schedule for feeding and insulin and should give them at the same time every day, 12 hours apart. Food should only be given with the insulin injections. This can be difficult for dog owners who are used to giving their dogs treats. Diabetic dogs should not receive food in between their insulin injections, because they do not produce insulin to help absorb the glucose in the treats. Often, ice cubes are recommended as treats for diabetic dogs. In addition to ice cubes, clean, fresh water should be available at all times.

There are diets formulated for diabetic dogs, but it is often recommended for the animal to remain on their original diet when initially diagnosed with diabetes mellitus. If a diabetic dog is not well-regulated on a strict feeding schedule and insulin, their insulin dose may be adjusted. If that is unsuccessful, and the dog does not have any other health problems that necessitate diet change, a diet for dogs with may be recommended as an additional management tool. These diets are usually high in specific types of fiber to help slow glucose absorption.

Diabetes in Cats

Cats usually get non-insulin dependent diabetes mellitus, which is similar to Type 2 diabetes in people. Cats with non-insulin dependent diabetes have cells that do not respond as well to insulin, and the cells do not absorb glucose well as a result. Many cats with diabetes mellitus produce more insulin to help the cells respond.

The “non-insulin dependent” terminology can be confusing, because cats with diabetes mellitus often require insulin injections. Insulin is needed in diabetic cats because the pancreas can eventually slow down insulin production after producing much more insulin than usual for a period of time. Cats receiving insulin injections may receive their insulin once or twice daily. This can depend on the type of insulin prescribed and the severity of disease.

Nutrition plays an important role in the management of diabetic cats. Because cats graze more commonly than dogs, it is difficult to keep them on a strict feeding schedule like dogs. If the cat will eat on a schedule, that can be very helpful. But because cats graze throughout the day, diabetic cats can benefit from consuming a low carbohydrate diet. This limits the amount of glucose that enters the bloodstream, keeping it lower throughout the day, even if the cat eats without receiving insulin.

Most low carbohydrate diets are high in both protein and fat, which means they should be fed in carefully measured amounts. Many diabetic cats are overweight or obese, and reducing their body weight can help them better respond to insulin. Therefore, it is especially important to measure the food that is given and for pet owners to feed the amount recommended by their veterinary team.

The combination of weight loss and insulin therapy can occasionally lead to what is called “diabetic remission” in cats. A cat in diabetic remission does not have physiologic or laboratory signs of having diabetes mellitus anymore. This can be temporary or permanent. It is important to continue to monitor the cat’s labs and signs, and also to keep them at an ideal body weight to prevent them from redeveloping signs of diabetes.