Diabetes: Animals with sugary blood

Image from andremsantana in Pixabay.com

Diabetes is a very old disease, firstly described in records written back to the Egyptian times. It is a common but complex pathology characterized by the abnormal rise of the sugar levels in the blood. After eating, the food is broken down and converted into a type of sugar called glucose. Glucose is then transported by the blood to the different organs to be used as a source of energy by the cells. But for the glucose to get inside the cells it needs the help of a hormone called insulin. Insulin is produced in the pancreas and diabetes takes place when the pancreas loses the ability to produce insulin or when the cells fail to respond adequately to it. In both cases, glucose is not capable to enter the cells resulting in an abnormal accumulation and increase of the levels of glucose in the blood. Most importantly, and if not controlled, this can bring serious complications and can even result in death. 

There are two types of diabetes. The type 1, or insulin-dependent, occurs when the cells from the pancreas do not produce any insulin, whereas the type 2, also named as insulin-independent, occurs when either the cell from the pancreas produce a reduced amount of insulin or when the cells of the organism do not respond adequately to the hormone. 

But diabetes is not a pathology unique to humans. All mammals produce and need insulin to be able to carry glucose inside the cells, so diabetes can affect a broad range of animals, such as monkeys, pigs, sheep or horses. Nevertheless, dogs and cats are the most afflicted by the disease affecting as much as 1 in 100 animals. Not surprisingly, studies have suggested that the incidence of diabetes has been rising in recent decades. This is mainly the result of the recent rise in life expectancy as well as the increase of unhealthy lifestyles in pets due to their closer proximity with human. Changes in diet, obesity and reduced physical activity are increasing risk factors accounting for the recent surge in number of cases observed in pets.

However, just like in humans, genetics can also increase the risk of the animals to suffer from certain types of pancreatic and immunologic diseases. For example, in humans, type 1 diabetes tends to affect more frequently Europeans, particularly those from northern Europe, whereas black and Asian individuals are at lower risk of contracting the disease. Equally, animals of different breeds undergo distinct risks for the disease. For instance, dogs from breeds such as Samoiedo, Terrier, Schnauzer, Collie and Poodle, as well as the Burmese cats, are more likely to suffer from diabetes than Boxers, German Shepherds and Golden Retrievers, who present low risk. Sex also plays a major role. Whilst in dogs, the females are more susceptible to diabetes, in cats are the males the most affected. But it is not just in terms of sex that dogs and cats differ. Whilst almost all cases of diabetes in dogs are type 1; the vast majority of cases in cats are type 2 (80-95%), similarly to what happens with humans. 

It is therefore very important to raise the owner’s awareness for the symptoms of diabetes in their pets. Unfortunately, just like in humans, the symptoms of diabetes in animals is very unspecific, making it difficult to diagnose the disease. Animals often show an excessive increase in hunger, thirst and in the volume and frequency of urination together with weight loss. In more advanced cases animals can suffer from blindness caused by cataracts (characterised by opacity in the eyes). The sooner the diagnosis is made, the better the prognosis, but unfortunately, most owners are only aware of the condition when it is already at an advanced stage and hospitalization is usually the only option. Nonetheless, in most cases, once blood glucose levels are lowered, the animal can return home. Daily insulin injections as well as exercise and proper diet are generally effective measures to control the disease and prevent future complications. 

It is important to understand that once regulated and monitored, many diabetic animals can live a happy and healthy life. 

Diabetes in Normal and Natural Conditions  
Recent studies have shown that some animals can also use “diabetes” in normal and natural conditions. That seems to be the case for the Grizzly Bears. During spring, they respond normally to insulin to prevent the breakdown of the fat tissue, but once hibernation starts, their insulin stops working and they become insulin-resistant to allow the breakdown of their fat storages throughout the winter. Once hibernation terminates, the insulin recovers and restarts working normally. Similar mechanisms have been seen in dolphins indicating they can also make themselves resistant to insulin during periods of fasting being able to switch diabetes “on and off”. 

Ricardo Ribas, PhD 
Veterinary doctor, doctorate in veterinary sciences and researcher in the area of oncology


The subjects and opinions discussed on this article are for informational purposes only. For more information consult your vet or a professional in the area.

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