About 1 in every 450 dogs will develop diabetes in their lifetime. Most cases are Type 1 (insulin-dependent) diabetes and usually appear in middle-aged to older dogs, typically between 7 and 10 years of age.
Diabetes in dogs happens when the body can’t properly use sugar for energy. Normally, insulin produced by the pancreas allows glucose (sugar) from food to move into cells, where it is used for energy. In diabetes, either the pancreas does not produce enough insulin (Type 1 Diabetes – most common in dogs) or the body cannot respond properly to it (Type 2 Diabetes – most common in cats). As a result, glucose builds up in the bloodstream while the body’s cells are starved of energy leading to widespread effects on organs and overall health.
Our bodies are made-up of 11 different systems that work together to keep us alive, each with its own important job. For diabetes mellitus, we need to visit the Endocrine System and more specifically, the part that controls the fuel supply to our body.
Our bodies run on a fuel called glucose, a type of simple sugar that normally provides most of the energy our cells need to function. To keep everything working properly, we need to keep the amount of glucose in the blood within a healthy range. For dogs (and humans), this is usually between about 80 and 120 mg/dL (4.4 to 6.6 mmol/L).
When blood glucose levels get too low too quickly (hypoglycaemia), cells in the brain, nerves, and blood which depend very heavily on glucose for energy can stop working normally. This can lead to weakness, shaking, confusion, and in severe cases, seizures, loss of consciousness, or even death.
When blood glucose levels stay too high for too long (hyperglycaemia), it can cause damage to many parts of the body, including the eyes, kidneys, nerves, and blood vessels. Early signs can include increased thirst, more frequent urination, tiredness, and blurred vision. If left untreated, serious complications can develop over time.
Fortunately for us, our bodies normally have a pretty good system for keeping everything under control.
Most of the glucose supply for our body generally comes from the carbohydrates we eat (unless we’re on a special low carb or no carb diet). These carbohydrates are broken down into simple sugars by special chemicals called enzymes, starting with ones in our saliva and then later by enzymes from the pancreas and small intestine. Once the sugars are broken down into small enough pieces, they get absorbed into the bloodstream and carried straight to the liver. There, any sugars that aren’t already in the form of glucose are changed into glucose. The liver then releases this glucose into the general circulation so it can travel around to the body’s cells and be used for energy.
Foods that are high in simple carbohydrates – like sugar, sweets, fruit juices, baked goods, white breads, white rice – have sugars that are already pretty close to glucose and will be processed very quickly in the digestive system causing blood glucose levels to rise very quickly.
Foods that are high in complex carbohydrates including fibre – like whole grains, vegetables, and legumes – that take much more work to break down are processed more slowly in the digestive system. This slow digestion leads to a gradual, steady rise in blood glucose levels, helping to maintain more stable energy levels and preventing sharp spikes in blood glucose that are bad for our health.
Special chemical sensors in the pancreas can tell when blood glucose levels start to rise, meaning there’s extra fuel available that needs to be stored away for future use. This triggers beta cells in the pancreas to release a hormone called insulin into the blood. Insulin acts like a messenger, (1) telling cells in the muscles and heart to pull glucose out of the blood and store it as glycogen — like filling up a fuel tank they can tap into for quick energy during activity or between meals and (2) telling our fat cells to store any extra glucose as fat, which the liver can later turn back into a different kind of energy (ketones) if we’re not getting enough calories from our food. The body is very good at knowing just how much insulin to release to get the blood glucose levels back to normal after eating without becoming hypoglycaemic.
If blood glucose levels start to fall too much or if cells aren’t getting the energy they need, the body has backup systems to keep things running. First, the liver can break down its stored glycogen to release more glucose into the bloodstream. If those stores run low, the liver can also make new glucose from other sources like amino acids (from protein) or by breaking down fat into another fuel type called ketones. This process helps keep vital organs, especially the brain, supplied with energy until normal glucose levels are restored or food is eaten again.
At its core, diabetes is a problem with how the body handles insulin — either the body doesn’t make enough insulin (Type 1 diabetes, also called insulin-dependent diabetes) or the body can’t use insulin effectively (Type 2 diabetes, also called non-insulin-dependent diabetes). In both cases, blood glucose levels can become dangerously high because insulin is essential for moving glucose out of the bloodstream and into muscle and fat cells where it can be used for energy.
Dogs almost always have Type 1 (insulin-dependent) diabetes and it usually develops in middle-aged to older dogs, typically between 7 and 10 years of age. About 1 in every 450 dogs will develop diabetes in their life. We still don’t know exactly what causes dogs to get diabetes, but it’s most likely linked to either pancreatitis (inflammation of the pancreas that’s often triggered by eating a very high fat meal) or an autoimmune problem where the body’s own immune system attacks and destroys the beta cells in the pancreas that make insulin.
There is currently no cure for Type 1 diabetes and most diabetic dogs need to be given daily insulin injections for life to replace what their body isn’t making. However, a dog with Type 1 diabetes can also face issues related to Type 2 (non-insulin-dependent) diabetes if they are overweight or obese. This insulin resistance can make it harder to manage their blood glucose levels, potentially complicating their diabetes management and requiring more careful attention to their diet and exercise to bring their Type 1 diabetes back under control.
Advancing Animal Care through Shared Learning