Diabetes in dogs is typically a multifactorial medical condition characterized by high blood sugar levels (hyperglycemia) resulting from inadequate or absent secretion of insulin. Insulin is a hormone produced by the beta cells of the pancreas, responsible for controlling blood glucose levels and for the uptake and use of sugar by body cells.
Hyperglycemia in dogs occurs when blood sugar (glucose) levels exceed 130 mg/dl, although symptoms and signs appear only when levels reach a critical range of 180-220 mg/dl. Common symptoms include glycosuria (glucose in the urine, which is typically glucose-free), polyuria (excessive urination), polydipsia (excessive thirst), and polyphagia (excessive appetite). These symptoms are accompanied by serious metabolic changes caused by the inability of body cells to utilize blood glucose, the body’s primary fuel under normal conditions. Among these complications, diabetic ketoacidosis is the most serious and life-threatening. This condition involves a dangerous drop in blood pH due to the excessive production of ketone bodies—by-products of fat metabolism. In diabetic dogs, fat degradation increases to generate molecules that can replace glucose as the primary energy source for body cells.
The most common form of diabetes in dogs is insulin-dependent diabetes, meaning affected dogs require exogenous insulin for life to control blood glucose levels. This occurs after the irreversible destruction and functional loss of pancreas beta cells. The exact causes of diabetes in dogs are not fully understood, but several factors are believed to contribute. These include breed and sex predispositions, infections, drugs and diseases that oppose insulin action, autoimmune diseases affecting the intestines, and pancreatitis. At diagnosis, most affected dogs are between 4-14 years old, with the highest prevalence occurring between 7-9 years. Female dogs are affected about twice as often as males. Certain breeds, such as Pulik, Cairn Terriers, and Miniature Pinschers, are at higher risk. Poodles, Basset Hounds, Miniature Schnauzers, and Beagles are also commonly affected, while breeds like the Cocker Spaniel, German Shepherd, Collie, Pekinese, Rottweiler, and Boxer seem to have a relatively low risk.
Diagnosing Diabetes in Dogs
The diagnosis of diabetes in dogs should always be made by a veterinarian. Owners may suspect diabetes if their pet shows increased urination, increased thirst, excessive appetite, and sometimes weight loss despite eating more. However, these symptoms are not exclusive to diabetes, as they are also seen in other diseases. A definitive diagnosis is made by confirming persistent fasting hyperglycemia in conjunction with glycosuria.
The primary goal in managing diabetes is to alleviate the symptoms associated with hyperglycemia and glycosuria. The persistence of clinical signs, such as excessive urination, thirst, and appetite, as well as chronic complications like ketoacidosis, fatty liver, pancreatitis, cataracts, and bacterial infections, are directly linked to the severity and duration of hyperglycemia. Therefore, effective treatment of diabetes in dogs revolves around maintaining tight control of blood sugar levels. This can be achieved through insulin therapy, a proper diet, adequate exercise, and treatment of any concurrent conditions (inflammatory, infectious, or hormonal disorders). The treatment regimen will depend on the number of functional beta cells in the pancreas and how the dog responds to the therapy.
Diabetic dogs require proper dietetic therapy to manage their condition. For dogs with obesity, this means correcting their weight, maintaining consistent meal frequency, and ensuring meals have a consistent caloric content that helps minimize blood glucose fluctuations after eating. A high-fiber diet can fulfill these needs. Many high-fiber diets for dogs contain primarily insoluble fiber (e.g., lignin, cellulose), with fiber content ranging from 3% to 25% of dry matter. In general, products with higher fiber content are more likely to help reduce body weight and improve blood glucose control. However, high-fiber diets are not without challenges. Common issues include increased defecation or constipation, as well as reluctance to eat these foods. If constipation occurs, adding soluble fiber, such as psyllium powder, can help. To encourage dogs to eat these diets, it may be advisable to introduce the new food gradually and alternate between different high-fiber options.
Dogs that are underweight should not be fed high-fiber diets due to their low caloric content. In these cases, insulin therapy is typically used to restore normal blood glucose levels, while feeding a maintenance diet with higher caloric density and lower fiber content. Once the dog reaches a healthy weight, the diet can gradually transition to one with higher fiber content.
