The Cats’ Unique Metabolism
Cats are unique, but heck you knew that already. Character aside though, cat digestion evolved along different lines to ours. Their ancestor cats survived by hunting small mammals and ate a meat-rich diet as a result. Their bodies learnt to be as efficient as possible and make the most of the available food (which was rats and mice). For thousands of years cats lived life as if all they had to eat is meat…because it was true…and their metabolism made no allowance for the need to turn vegan.
These metabolic adaptations are both a cats’ strength and their weakness (and why they are unable to detox and breakdown many human pharmaceuticals.) It’s why they were able to survive in arid environments (their kidneys harvest water from their prey) and created a highly efficient way to survive in an environment of limited resources.
The major metabolic differences are:
- Cats require high quality protein to be healthy.
- Cats require a supply of taurine in their diet.
Let’s cross reference this with a vegan diet.
What is a Vegan Diet?
A vegan diet is vegetarianism taken to the next level by excluding any animal-derived ingredients, such as eggs, milk, and dairy products.
All bodies need protein to function, and since meat is off the menu vegans get their protein from grains, pulses, beans, and legumes. These plant-derived proteins are technically known as being of ‘low biological value’ when it comes to nourishing the body. The latter is a term used by nutritionists to describe how useful a food is. The lower the biological value, the less likely it is to be a good source of nutrition.
Low biological value with regards to plant proteins means they don’t contain all the ‘amino acids’ necessary for tissue growth. But the good news for us humans is our bodies found a way round this deficiency. As omnivores, our bodies have learnt to use plant-based proteins as building blocks with which to manufacture those missing amino acids. Thus, although pulses don’t contain taurine, we dodge the issue by manufacturing our own from the raw building blocks in the protein.
Amino acids and proteins are vital for body functions such as tissue growth, repair and healing, making haemoglobin, myoglobin, and as part of the vital immunoglobulins that make up our immune system. So switching back to cats, they need protein of ‘high biological value’ such as meat, with all the amino acids ready supplied. If they don’t get everything they need, there is no compromise; they become taurine deficient and extremely ill.
Taurine Deficiency in Cats
If you feed your cat a vegan diet there is no doubt that they will become taurine deficient. Taurine is needed for:
- Platelet function (deficiency leads to impaired blood clotting)
- Growing healthy bones (deficiency leads to skeletal deformities in kittens)
- Hair growth
- Healthy heart muscle (deficiency causes dilated cardiomyopathy or DCM)
- Healthy eyesight (deficiency leads to retinal disorders and blindness)
Of these, the most serious are dilated cardiomyopathy (DCM) and blindness.
It was as late as 1987 that the link between a lack of taurine and DCM was first made. For decades it had been recognised that cats on a vegetarian diet fared badly, of which a classic sign was early death from heart failure. This was also around the time when cardiac ultrasound scans were in their infancy, and vegetarian cats supplied a steady source of cases to veterinarians to study.
But it was UC Davis, Veterinary teaching hospital that realised all the cats they were studying with heart failure were also testing taurine deficient. Then, to their surprise when the cats were given taurine-supplements for 2 – 3 months, their heart function started to improve. The response was so marked that they named this new condition ‘taurine deficiency induced myocardial failure’, but this being a bit of a mouthful to say, the shorter name DCM (which describes the appearance of the heart) took off.
Long story short, if you genuinely want the best for your cat, then please respect their need to eat meat. If you are tempted to get round the problem by supplementing a vegan diet with taurine, remember the latter is only part of the picture. The proteins are still of low biological value which means your cat is liable to have a poor coat, weak immune system, and be at risk of problems with their circulation and blood clotting.
Embrace the cat as a carnivore and know you are doing the humane thing by feeding them the diet that nature intended.
This blog post is part of the quarterly campaign for Be the Change for Animals – advocating to make the world a better place for all animals.