Updated: Jul 7, 2022
This is a 3 Part Series of covering Kidney Disease in Pets (Cats More Specifically)
Articles covered in this series;
Chronic kidney disease is also known as chronic renal failure (CRF) is reaching epidemic proportions in our pets. It can affect both dogs and cats: 1 in 10 dogs and 1 in 3 cats are at risk of developing the disease at some stage in their life. (1) So why is it so common and what can we do as pet parents to reduce the risk of or slow the disease? To prevent kidney disease in people, we are encouraged to live a healthy lifestyle with regular exercise and healthy diet. Yet, when it comes to our pets the information about prevention of this potentially deadly condition is sparse and inconsistent. This is incredibly frustrating for loving pet parents that want to do better for their pets – and the only way this is going to change is if we all work together to demand better for our pets!
Understanding Kidney Disease
There are two types of kidney failure: acute (ARF) and chronic (CRF). Acute kidney disease is a more temporary form that develops suddenly over hours or days. It may be a result of some sort of trauma such as poisoning, drug overdose, injury, kidney infection, rapid blood loss, kidney blockage or heart failure. If the underlying cause is discovered, the kidneys can be managed and symptoms of failure can be reversed. If cause is severe, it could lead to a chronic form of the disease.
Chronic renal failure (CRF) is a deterioration of the kidney tissue and function over several months or years. It is generally discovered at a later stage of development when a pet starts to present with severe clinical symptoms such as increased thirst, increased urination (PU/PD), weight loss, dull coat and/or low appetite. These are serious signs that should be addressed by a veterinarian immediately. Again, these symptoms don’t happen overnight!
Generally, vets will look at blood samples to determine the cause of the symptoms. Pets with renal disease will have high blood urea nitrogen (BUN), high creatinine and high hematocrit. Urine specific gravity will often be low as the kidneys lose their ability to concentrate urine waste.
Dr. Karen Becker DVM explains in great detail the nature of chronic kidney disease here.
Why Cats Get Kidney Disease More Often Than Dogs
The cat’s closest relative is African Wildcat (Felis sylvestrus lybica) who evolved in a desert climate. This produced some unique metabolic traits including the ability to conserve water. For this reason, cat have an extremely low thirst drive compared to other mammalian species. (2) They don’t drink water readily, even when they are dehydrated. This leaves them in a precarious state, especially when it comes to common modern nutrition practices for cats and by that I mean dry food!
Why Dry Food is Downright Dangerous
You can’t control if your pet ends up with kidney disease, but we believe that you can significantly reduce the risk by feeding high quality fresh food diet that’s high in moisture.
The strong correlation between CRF and poor nutrition (3) (4) stems from a few key factors:
Dry Foods Contain Dangerously Low Moisture.
Feline and canines normally get between 70-80% water content from their natural diet and for good reason. Their body uses that water to help in the digestion process. This is important! With dry food meals, your pet will consume the meal and while it’s in the stomach, the body must take water from its internal stores to break down the dry food into a digestible form (known as chyme). This leaves an animal dehydrated and thirst is the response to that dehydrated state. This is especially severe in the case of kitties since they don’t get thirsty easily. It’s a vicious cycle of constantly re-hydrating the body rather than the body staying hydrated all the time.
Most Dry Foods Contain Low Quality or Over-Processed Protein Sources.
Eg. By-products and inappropriate processed plant proteins such as soy and chick peas). Since, protein wastes are ultimately filtered through the kidneys, low quality protein can add unnecessary stress or even damage the kidneys over the long term.
Dry Food May Contain Rancid Fat and Toxic Chemicals in the Form of Preservatives.
While omega 3 fatty acids are proven to be extremely beneficial for kidney disease, rancid sources could cause the opposite effect. (5) Fish oils are often sprayed onto dry food to increase omega 3 content but as soon as they are exposed to air, they begin to break down and can become harmful if ingested on a long-term basis. Toxic preservative chemicals such as BHA, BHT and ethoxyquin are often used to preserve food. These chemicals have been linked to several forms of cancer and immune system dysfunction. (6) (7) (8) (9)
Some Important Nutrients Missing From Dry Diets Include Natural-Sourced Vitamins and Natural Enzymes are not Recognized as Important by Feed Control Officials.
These nutrients aid in gut and immune health, provide important antioxidants and disease-fighting properties as well as aid in the body’s overall function and homeostasis. When these ingredients are missing (as they are in highly processed foods), coupled with dehydration and high toxin load, it can become a really big problem for the kidneys.
There are only a few holistic veterinarians who have really publicly spoken out on the subject such as Dr. Becker. I must commend her for doing this since she’s taken some flack from the veterinary community for it because it’s not what’s taught in vet school. One must come to this conclusion through clinical experience, not out of a textbook. Check out her video on feline kidney disease here.
Shifting the Odds
We believe that as pet parents, we CAN take steps to reduce the risk of kidney disease and shouldn’t be treat it as something that animals are just predisposed to. Diet has a huge role to play! The first sign of kidney dysfunction is the regular consumption of water by your pet, especially cats. Your pet could have normal looking blood results on a dry food diet for years while still displaying clinical symptoms of dehydration…..until one day, blood results come back abnormal. The kidneys can handle a lot of stress but they do have a breaking point. So, if your pet is drinking a lot, this should be your que to make some changes. And you don’t have to wait until your pet is in chronic kidney failure – you can make changes now to reduce stress on the kidneys so they remain healthy and happy for as long as possible.
Here are some strategies you can use to reduce risk of kidney disease:
Feed a raw diet made of fresh, minimally processed ingredients
Feed a cooked diet made of fresh, minimally processed ingredients
Feed a good quality canned diet with quality, real food ingredients
Add broth to the kibble to increase moisture content - for more info check out our blog about BONE BROTH.
More on Kidney Disease
Read Part 2 and Part 3 where we’ll discuss how to prevent kidney disease and why common kidney diets won't work. In Part 3 we will cover strategies for what you can do to help your pet with kidney disease.
2. Adolph EF. Tolerance to heat and dehydration in several species of mammals. American Journal of Physiology 1947;151:564–575.
3. Dry Food and Risk of Disease in Cats: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2387258/
4. The Dangers of Dry Food: https://feline-nutrition.org/health/species-inappropriate-the-dangers-of-dry-food
5. Effect of oxidized fish oil, vitamin E and ethoxyquin on the histopathology and hematology of rainbow trout: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2761.1984.tb00932.x
6. The Poisons in Pet Food: http://www.essentials4all.org/poisons-in-pet-food.html
7. The synthetic antioxidant, ethoxyquin, adversely affects immunity in tilapia: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2095.2008.00577.x
8. Chemoprevention of cancer: phenolic antioxidants (BHT, BHA): https://www.ncbi.nlm.nih.gov/pubmed/3053283