Taurine in animals: heart and cats

What is taurine?

Taurine is a sulphur-containing amino acid that plays a role in cardiac muscle function, retinal integrity, bile salt formation and antioxidative processes. For dogs it is considered semi-essential: they can synthesise taurine themselves, but sometimes insufficiently. For cats taurine is strictly essential: cats lack the enzymatic capacity to synthesise sufficient taurine from cysteine and methionine and are entirely dependent on their diet.

What is it used for?

Cats — heart, eyes and reproduction

In cats with taurine deficiency, three syndromes are clinically documented:

• Dilated cardiomyopathy (DCM): the heart muscle weakens and enlarges, resulting in heart failure.
• Central retinal degeneration: progressive degeneration of the retina leading to permanent blindness.
• Reproductive disorders: reduced fertility and increased perinatal mortality in kittens.

A clinical study showed clear echocardiographic improvement after taurine supplementation in 59% of cats with DCM — even after discontinuation of all other medication [1]. The discovery of feline taurine deficiency in the 1980s led to all commercial cat food being mandatorily enriched with taurine since then. Feline DCM has decreased sharply thereafter, which epidemiologically supports this association.

Dogs — grain-free diet and DCM

In dogs, taurine-related DCM is less frequent, but has been described in certain breeds — notably Golden Retrievers on grain-free or legume-rich diets. A prospective cohort study showed a relative risk of 9.8 for taurine deficiency and 15.0 for echocardiographic dysfunction on this diet [2]. The exact mechanism has not yet been fully elucidated; legumes appear to disrupt the absorption or endogenous synthesis of taurine. Further research is ongoing.

Evidence overview

The evidence for cats is robust: multiple clinical studies and decades of practical experience following mandatory dietary supplementation confirm the picture [1][2]. In dogs, the basis is solid for risk groups, but less complete for the general population.

Safety

Taurine has a favourable safety profile at usual veterinary doses. No known toxicity threshold has been described. Supplementation is well tolerated, also in the long term.

Points of attention regarding diet: homemade, vegetarian or vegan cat food almost always contains insufficient taurine unless carefully supplemented. The same applies to dogs on experimental diets with a high proportion of legumes (lentils, peas, chickpeas).

Dosage

Dosage varies per animal, body weight, diet composition and clinical picture. Always have this determined by a veterinary surgeon, who can also assess the need for echocardiography or blood testing.