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Taurine in dog and cat diets

A short guide to the role of Taurine in dog and cat nutrition.

Taurine

A specific sulfur amino acid that does not build muscle proteins, but occurs in free form in the tissues. Its highest concentration is found where cells work hardest: in the heart, the retina of the eye, the brain and the muscles. It is key to fat digestion, because it binds with bile acids [1].

The species difference here is fundamental. The dog is able to produce taurine in the liver from methionine and cysteine (see Methionine and cystine), so on a well-formulated meat diet deficiency is rare in it — NRC classifies taurine in the dog as conditionally essential [1]. The cat practically lacks this ability (negligible activity of cysteinesulfinic acid decarboxylase), and on top of that constantly loses taurine through the obligatory conjugation of bile acids — it cannot switch to glycine the way the dog can. That is why for the cat taurine is an amino acid that is absolutely essential from the diet, daily [1]. Taurine escapes with water — pouring out the juice after thawing meat or the broth after cooking is a waste of taurine.

Where it's found: Exclusively in animal tissues. The richest and most reliable source is heart (chicken, beef, turkey, lamb) — counted in BARF as muscle meat, not offal. Dark meat (thighs, drumsticks, duck) has considerably more taurine than light meat (breast). Roughly: beef heart about 60–120 mg/100 g, chicken thigh about 30–60 mg/100 g — but the content in meat is highly variable, even 2–3-fold between batches [1]. In cats, additional supplementation with pure taurine is a frequent practice.

Deficiency: Develops covertly — by the time symptoms become visible, some of the changes are already irreversible. In the cat it is a multi-organ catastrophe: dilated cardiomyopathy (DCM, potentially fatal) [2], central retinal degeneration leading to irreversible blindness [3], reproductive problems and litter defects. In the dog deficiency is rarer, but possible — above all DCM [4]. The risk is higher in predisposed breeds (golden retriever, Newfoundland, American cocker spaniel, some Doberman lines), even on a good diet [5]. It is also favored by a large share of fiber or legumes and by intestinal dysbiosis [6].

Excess: Practically does not exist. Taurine is water-soluble, and its excess — whether from diet or supplement — is efficiently excreted in the urine [1]. It is precisely this risk profile (irreversible deficiency vs. zero risk of excess) that justifies the safety margin in the form of supplementation in cats.

Supplementation — when it makes sense

In the dog on a typical meat BARF, routine supplementation is not needed; it is worth considering only in predisposed breeds, with intestinal diseases, after antibiotic therapy, or with a diet rich in fiber. In the cat a dose of 250–500 mg daily is a frequent, sensible safeguard — taking into account the large variability of taurine content in meat and the unpredictable losses during grinding and freezing. It is possible to formulate a correct diet without heart, if taurine is calculated and topped up with a supplement. Cats with already diagnosed DCM require therapeutic doses under veterinary supervision [2].

Sources

  1. National Research Council (NRC) (2006). Nutrient Requirements of Dogs and Cats. National Academies Press. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats
  2. Pion PD, Kittleson MD, Rogers QR, Morris JG (1987). Myocardial failure in cats associated with low plasma taurine: a reversible cardiomyopathy. Science 237(4816):764-768. https://doi.org/10.1126/science.3616607
  3. Hayes KC, Carey RE, Schmidt SY (1975). Retinal degeneration associated with taurine deficiency in the cat. Science 188(4191):949-951. https://doi.org/10.1126/science.1138364
  4. Sanderson SL (2006). Taurine and carnitine in canine cardiomyopathy. Vet Clin North Am Small Anim Pract 36(6):1325-1343. https://doi.org/10.1016/j.cvsm.2006.08.010
  5. Kaplan JL, Stern JA, Fascetti AJ, et al. (2018). Taurine deficiency and dilated cardiomyopathy in golden retrievers fed commercial diets. PLoS ONE 13(12):e0209112. https://doi.org/10.1371/journal.pone.0209112
  6. McCauley SR, Clark SD, Quest BW, Streeter RM, Oxford EM (2020). Review of canine dilated cardiomyopathy in the wake of diet-associated concerns. J Anim Sci 98(6):skaa155. https://doi.org/10.1093/jas/skaa155