Pet Health:
Diabetes in Dogs and Cats, updated 6/19/2002

Diabetes can affect both cats and dogs.  Insulin, which is the hormone responsible for moving sugar into the cells of the body, is produced by an organ in the body known as the pancreas.  Inflammation or infection of the pancreas (pancreatitis), can result in a decrease in production of insulin hormone.  Obesity can lead to an overproduction of insulin from the pancreas, with a subsequent "burn out" of the gland, resulting in a decrease in production of insulin hormone.

Decreased insulin production leads to a high level of sugar accumulating in the blood stream.  Without the carrier hormone insulin, the cells of the body tend to "starve", as sugar or glucose is no longer able to enter the cells.  The body responds to this "starvation process" by breaking down its own source of energy and sugar stores to make up for this apparent starvation.  However, without the necessary insulin hormone to carry the sugar into the cells, this breakdown of energy stores is fruitless. 

Excess sugar in the blood stream then is carried to the kidneys where it is excreted as waste material.  With the sugar is carried an excess of water from the kidneys.  Therefore, the patient water consumption increases due to this excessive loss of water from the body.

Thus, the symptoms the diabetic patient normally demonstrates include abundant water drinking and weight loss in the face of a normal or greater than normal appetite.  If the disease is allowed to progress, fat breakdown products will accumulate, and most patients will decrease or stop eating altogether.  Vomiting can occur, and dehydration because of water loss is common.  Death can occur if left untreated.

The treatment for a diabetic patient, is to replace the insulin they are deficient in back to the body.  If the patient's condition has progressed and dehydration, vomiting, and no appetite exist, fluid replacement and supportive care of these patients in hospital is usually necessary.  Replacement of insulin is done when these patients have stabilized.

Insulin must be administered to the patient by injection.  Two daily injections are typically spaced apart and given with meals.  Injection is done under the skin, using a very small needle.  Most insulin and syringes used today, are the same as used by human diabetic patients.

Once learned, the injections are fairly easy to do, and usually quite tolerated by the patient, whether they be cat or dog.  Periodic blood sugar testing, or at home urine testing for sugar, can be done to adjust the dose of insulin required for the patient.

Diet adjustment can be of extreme assistance especially if the patient is overweight.  Diets high in fiber are the best choice for the diabetic patient.  High fiber diets help to decrease the surge of blood sugar absorbing from the intestines, while reducing the patient's weight.  Obese patients therefore benefit greatly from higher fiber diets, and insulin dosage can be lowered by feeding a high fiber diet. 

Some cats can be completely taken off of insulin, and maintained only on a high fiber diet (or recently, high protein diets have been instrumental in the treatment of feline diabetes - see below).  Dogs appear to require insulin for life, unless their diabetes has been brought on by an inflammation in the pancreas, which corrects itself, and has not damaged the insulin producing cells.

Recent research into diet and diabetic control in the feline has resulted in a mild breakthrough in the treatment of type 2 diabetes in the cat. Type 2 diabetes typically occurs in cats fed a dry cat food diet in a free feed fashion. These cats are typically obese, and allowed to eat whenever they wish. An increase in thirst and appetite accompanied by weight loss, often are early symptoms that type 2 diabetes is present.

Up until now, we have treated cats as if they were small human beings, and have dealt with their diabetic condition in such manner. However, cats are carnivores by nature, and have different physiological mechanisms by which they handle nutrients such as fats and proteins and carbohydrates from that of their human counterparts.

A study which included a set of type 2 diabetic cats, were given a high protein, high fat diet low in carbohydrates. Another group of type 2 diabetic cats were fed a diet high in fiber. Both groups of cats were receiving daily doses of insulin for their diabetes. All cats had their body fat content critically analyzed as well.

Most cats in each group lost weight. Some cats actually gained weight on the high protein high fat , low carbohydrate diet. However, when compared to their prior fat analysis, the cats that had gained weight actually lost body fat and replaced it with muscle weight. 67% of the cats fed the high protein, high fat, low carbohydrate diet were actually able to discontinue the need for insulin, compared to 23% of the cats fed the high fiber diet.

This study seemed to highlight the importance of treating the cat true to its own physiology. As carnivores, cats do not naturally consume carbohydrate in their diets. However, dry foods to maintain their 'dry form' need carbohydrate in order to do so. Overfed cats on this high carbohydrate diet become obese, and therefore run the risk of developing type 2 diabetes.

Some cats with type 2 diabetes can be controlled with oral medication which lowers the blood sugar content, however, most cats require twice daily administration of insulin given by injection. This form of therapy is not accepted by all, and can be difficult for owners to go away leaving the cat in the care of others.

Until now, it was always thought that these cats on insulin would usually remain on this therapy throughout their lives. However, with the advent of this new research, more and more cats are now being free of their dependency upon insulin injections.

Preferred foods for the diabetic cat include canned science diet kitten formula (this is what was fed to the cats in the study), or any other canned kitten formula. Next preferred would be canned cat food of a named brand. Thirdly, if the cat is simply 'hooked' on eating dry food only, feed small amounts of the dry food 3-4 times/day, rather than allowing the cat to have free access to the food.

Treatment of the diabetic patient should be considered as the patient's life can return to normal activity and quality with minimal discomfort to them at minimal cost to the owner.  Another useful website for the feline diabetic is: http://www.felinediabetes.com/.