7 Common dog illnesses that are affected by poor nutrition

Written by Dr Andrew Miller MRCVSDr Andrew Miller MRCVS is an expert veterinary working in the field for over 10 years after graduating from Bristol University. Andy fact checks and writes for Pure Pet Food while also working as a full time veterinarian. Pure Pet FoodPure Pet Food are the experts in healthy dog food and healthy dogs featured in media outlets such as BBC, Good Housekeeping and The Telegraph. Working with high profile veterinary professionals and nutritionists, Pure Pet Food are changing dog food for the better. - Our editorial process

A balanced, nutritious diet is vital in making sure your pup is happy and healthy. Poor nutrition is a contributing factor in many dog illnesses, making it important to feed your pooch high-quality food to help prevent them from falling ill. Think of it as investing in their health now, so they don’t get ill later.

A life on junk food can take a toll on a dog’s body, initially your dog might seem fine but over time their health is more likely to deteriorate and complications arise.

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Your dog relies on getting adequate nutrition in order to support all their bodily functions. This includes supporting a healthy immune system, avoiding certain ailments, maintaining strong bones, normal cell function, and growing strong claws and healthy fur.

A poor diet can cause or contribute to a number of dog illnesses, including:

There are many more canine illnesses with links to diet. But we will explore some of the common conditions that your dog might be susceptible to that are directly impacted by what they eat and their nutrition.


Obesity is one of the most common problems facing pets, and it is one of the most preventable. It is estimated that around 45% of dogs in the UK are overweight and the number is rising each year.

Obesity is when a dog has an excess of body fat. It is linked with many other problems for dogs, such as decreased lifespan and higher susceptibility to other illnesses such as diabetes, and heart disease.

Excess fat is a consequence of poor diet, overfeeding, and lack of exercise. As such, making sure your dog exercises regularly and eats a high-quality diet in an appropriate volume is important to prevent and treat obesity and the secondary conditions it is associated with.


Pancreatitis has no known cause; however, one factor that contributes to an increased risk of illness is poor nutrition because eating food that is high in carbs and fat forces the pancreas to work harder to produce the enzymes that break down food.

Diet is such a crucial factor in the prevention of this disease that any dog who has suffered pancreatitis will need to have a monitored diet while recovering, and avoid high-fat food and treats to prevent future episodes of the illness.


Diabetes in dogs is often associated with a poor diet. There are two forms of diabetes in dogs, and the most common is diabetes mellitus. Diabetes mellitus is caused by a lack of insulin, and it can be genetic. However, it can also be a secondary condition related to obesity or chronic pancreatitis, which are both affected by poor nutrition.

The second form of diabetes, diabetes insipidus, is much rarer and idiopathic, occurring spontaneously and having no known cause.

A dog with diabetes will need treatment for life, including the provision of insulin. However, feeding them a high-quality diet will help control their blood sugar levels, making it important as both a preventative factor and as a key part of managing the illness.

Gastrointestinal illnesses

There are a number of illnesses that affect a dog’s digestive system. These conditions can include gastrointestinal distress, colitis, gastroenteritis, gastritis, and many more.

Although there are a number of causes for these illnesses, diet is a significant contributing factor. In addition, a good diet of highly digestible food is part of the treatment for most gastrointestinal issues and feeding your pooch a good diet is a great preventative measure against such illness.

Heart disease

Just like with humans, dogs can suffer from heart disease caused by fat build-up in the arteries around their heart. These deposits are usually created by preventable problems such as poor nutrition and lack of exercise. Age, breed, and previous infection or heartworm can also contribute to a dog’s likelihood of developing heart disease.

However, you cannot prevent your dog from ageing or change their genetics. That is why proper nutrition and exercise is so crucial in helping to minimise your dog’s risk of illness and preventing heart disease.


Sadly, cancer is common in dogs. The causes of cancer vary and are difficult to diagnose. However, just like with people, eating a healthy, balanced diet plays an integral part in lowering a dog’s risk of developing cancer. Being overweight also contributes to the likelihood of developing cancer, making it even more important to ensure your pooch has a good diet.

Additionally, some studies have shown that diet can influence the progression of cancer and improve a dog’s quality of life even if they have the illness.

Skin & fur conditions

When a dog is not getting enough nutrients from their food, a clear indication is in their skin and fur. If your pooch isn’t eating enough nutritious food or absorbing their food properly, their fur will become dull, dry, brittle and sometimes itchy. They may also experience thinning of their fur and even hair loss.

Meanwhile, poor nutrition is the largest cause of recurring skin conditions in dogs. Feeding nutritious food will not only prevent some conditions, but it will also help to strengthen the skin barrier to prevent allergens from penetrating the skin and thus lowering the chances of future problems.

Hair loss and skin infections can also be caused by dietary allergies. This makes it all the more important to ensure you feed your pooch a highly nutritious food that avoids the offending allergen.

Written by: Dr Andrew Miller BVSc MRCVS

Andy graduated from Bristol University in 2010 and sees nutrition as a foundation for our pet's wellbeing and takes a common-sense approach. We are what we eat, and it shouldn't be any different for our pets.