Taurine: should you supplement your cat’s diet?
In today’s article we are going to talk about taurine: what is it, why is it so important, and the question that everyone asks: should I add taurine to my cat’s raw diet?
What is taurine?
Taurine is an essential amino acid for cats (more precisely, it is a beta-amino sulfonic acid). Essential means that cats, contrary to dogs, cannot synthesize it and so it must be provided in their diet.
Taurine plays a role in many body functions such as growth, reproduction, sight, heart function, neuromodulation, immune response, fetal development…
A deficiency in taurine will lead to feline central retinal degeneration and blindness, dilated cardiomyopathy and heart failure which will result in the cat’s death, and other disorders such as inadequate immune response, poor neonatal growth, poor reproduction, congenital defects…
Excess taurine is non-toxic as it is excreted through the urine. [6][7]
How much taurine does my cat need?
There’s no one-size-fits-all answer regarding the nutrient requirement of cats in taurine: it depends on the cat’s diet.
The recommended allowance defined by the NRC is 100mg of taurine per 1000kcal for a purified diet, which is a highly digestible diet used in nutritional studies to determine nutrient requirements.
For dry food such as kibble, the NRC recommends 250mg per 1000kcal (equivalent to 0.1% on the dry matter for a 4000kcal/kg diet).
For wet food such as canned food, the NRC recommends 425mg per 1000kcal (equivalent to 0.17% of dry matter for a 4000kcal/kg diet). [1]
This difference is to account for the bioavailability of taurine in the different diets. In fact, some elements of the diets can reduce the availability of taurine. These elements are mainly the amount and type of fiber and proteins, and the degree of heat processing of the diet.
In fact, some fibers such as rice bran or protein compounds can bind with the taurine in the small intestine and make it unavailable for the cat.
High levels of proteins increase the taurine requirement, as well as low-quality proteins.
Regarding heat processing, the cooking of certain proteins with sugars results in the creation of Maillard products. These products are less digestible than untreated proteins and they favor the development of bacteria that degrades the taurine in the gut. The bacteria will degrade the taurine and make it again unavailable for the cats. Canned food contains higher levels of Maillard products, which explains why it has the highest requirement for taurine. Similarly, dry food also contains Maillard products and high fiber levels. [2][8][9][10][11][13]
For a raw diet, it gets more complicated as there is no official recommended value.
In one study, cats were fed a diet made of whole ground rabbits and developed a taurine deficiency. [5] However, a future study showed that rabbit is a type of meat particularly low in taurine: the taurine quantity in rabbits is inferior to the recommended allowance defined by the NRC for a purified diet, which would explain the taurine deficiency when cats were only fed with rabbits. [3]
One study recommended using the same guideline as for kibble for a raw diet, as raw diets contain bacteria that are susceptible to destroy taurine. [3] This would result in a recommendation of 250mg per 1000kcal or 0.1% of dry matter for a diet at 4000kcal/kg.
What affects taurine?
Contrary to popular belief, taurine is not destroyed by cooking. However, taurine is water-soluble. Therefore, during any type of processing (including cooking) some taurine can be lost in the water. If the meat is cooked in water (boiled or steamed), it will lose more taurine than if it were baked.[4] However, while there still is some taurine in the cooked meat, if there are Maillard products created during the heat process, the bioavailability of the taurine will be reduced.
Similarly, some water is released when frozen meat is thawed: in this water called myoglobin, some of the taurine is lost.
Finally, there’s also some water loss when meat is ground. Additionally, grinding also increases the exposure of the meat to air, which develops bacteria (and, as we have seen, taurine is susceptible to bacterial degradation).
Where is taurine found?
Taurine is found almost exclusively in animal products. It’s found in the highest concentration in seafood, hard-working muscles such as the heart and tongue, and poultry dark meat (meat from the thigh). Smaller animals are richer in taurine than bigger animals and whole prey such as mice, rats, day-old chicks, and quails are quite rich in taurine.
However, some other meats such as rabbit, poultry light meat (breast) are low on taurine.
Mechanically deboned meat is also particularly low on taurine, probably due to the fact that the meat is low quality and processed.
Taurine is not present in fruits, vegetables, legumes, cereals, nuts, or other plant products. However, it’s present in small amounts in yeast, seaweeds, and fungus. [4]
If you look for the amount of taurine in various cuts in nutritional databases such as the USDA, you won’t find any information on it. In fact, as taurine isn’t essential for humans, the food is not routinely analyzed for its content in taurine. There are surprisingly few studies reporting taurine amounts in foodstuff. At the end of this article I will include a table with the taurine content in different relevant foodstuff for raw feeding.
Example of taurine amounts in a raw diet
Example 1
I calculated the amount of taurine in the example of the NRC balanced diet that I described in this blog article. The amount of taurine in the diet was 213mg (I didn’t calculate the amount of taurine for the organs and the cooked mussels because I don’t have their values).
The daily requirement in taurine for Praline (my 3.7kg cat) is 24mg for an NRC purified diet, 59mg for an NRC dry diet, and 101mg for an NRC canned diet. So, even for the strictest requirement, the diet meets (and exceeds) the NRC recommendations.
Example 2
Let’s consider a PMR recipe with a daily ration of 120g, which is approximately 3% of Praline’s weight:
20g chicken necks, 20g beef hearts, 6g beef liver, 6g pork kidney, 12g mackerel.
If the meat used for the last 56g is turkey, the total amount of taurine will be 108mg, meeting (and exceeding) all the NRC recommendations.
If the meat used is beef, the total amount of taurine will be 80mg: we exceed the NRC recommendation for a purified diet and a dry diet.
If the meat used is chicken breast, the total amount of taurine will be 64mg, which still exceeds the NRC recommendation for a purified diet and a dry diet, even if chicken breast is a type of meat that is very low on taurine.
When should you add taurine, and how much?
Generally, a raw diet provides enough taurine without supplements, especially if you feed around 20% of your cat’s diet with taurine-rich cuts: hearts, lungs, tongue, dark meat from poultry.
However, if you feed a diet predominantly composed of low taurine cuts such as rabbit or chicken breast, or you grind your cats' diets, adding taurine is a good idea.
In fact, when in doubt you can just supplement taurine as it is non-toxic. You will find below a calculator with the 3 guidelines of the NRC.
To conclude, taurine is an essential nutrient for our cat, and a severe taurine deficiency can lead to the cat’s death. Most raw meat provides enough taurine for your cats, especially hearts, lungs, and tongue. Don’t forget to feed the residual water after thawing your meat as it contains the taurine lost from the meat. If you feed ground meat, a cooked diet, or mainly rabbit you should supplement taurine to your cat diet.
Extra tools
This calculator is made using the metabolic weight formula:
For purified diet 9.9mg per kg/BW^0.67 equivalent to 100mg per 1000kcal
For dry diet 24.75mg per kg/BW^0.67 equivalent to 250mg per 1000kcal
For canned diet 42.075mg per kg/BW^0.67 equivalent to 425mg per 1000kcal
Taurine in raw meat
| Cut | mg of taurine / 100g wet weight | mg of taurine / 1000kcal |
|---|---|---|
| Beef | 43 | 246 |
| Beef, ground, <15 fat | 40 | 190 |
| Beef, ground, <25% fat | 28 | 97 |
| Beef, ground, <30% fat | 36 | 109 |
| Beef, heart | 65 | 582 |
| Beef, kidney | 23 | 227 |
| Beef, lean | 31 | 237 |
| Beef, liver | 69 | 510 |
| Beef, lung | 96 | 1039 |
| Beef, mechanically deboned | 8 | 28 |
| Beef, round | 36 | 241 |
| Beef, spleen | 87 | 832 |
| Beef, tongue | 175 | 782 |
| Beef, udder | 22 | 117 |
| Chicken, dark meat | 169 | 1352 |
| Chicken, ground | 61 | 350 |
| Chicken, head and feet | 50 | 250 |
| Chicken, heart and liver | 118 | 791 |
| Chicken, leg | 34 | 279 |
| Chicken, liver | 110 | 924 |
| Chicken, mechanically deboned | 46 | 197 |
| Chicken, neck and back | 58 | 292 |
| Chicken, raw boneless skinless breast | 16 | 133 |
| Chicken, whole carcass | 100 | 498 |
| Duck, ground | 56 | 215 |
| Duck, leg meat | 178 | 1319 |
| Horse, meat | 31 | 236 |
| Lamb, kidney | 24 | 246 |
| Lamb, leg | 47 | 210 |
| Lamb, stew boneless | 216 | 1610 |
| Pork, kidney | 77 | 773 |
| Pork, liver | 86 | 638 |
| Pork, loin | 61 | 508 |
| Pork, lung | 78 | 912 |
| Tukey, light meat | 30 | 263 |
| Turkey | 93 | 810 |
| Turkey, dark meat | 306 | 2833 |
| Turkey, ground, 7% fat | 210 | 1397 |
| Veal | 40 | 276 |
Taurine in fish and sea food
| Cut | mg of taurine / 100g wet weight | mg of taurine / 1000kcal |
|---|---|---|
| Capelin, whole | 144 | 1596 |
| Clam, fresh | 240 | 2963 |
| Cod | 31 | 383 |
| Herring, whole | 154 | 977 |
| Mackerel, whole | 207 | 1010 |
| Mussel | 655 | 9097 |
| Oyster, fresh | 70 | 1042 |
| Salmon, fillet atlantic fresh | 130 | 915 |
| Scallop | 827 | 2356 |
| Squid | 356 | 4623 |
| Tuna | 200 | 1388 |
| Tuna, red meat | 280 | 1943 |
Taurine in whole prey
| Cut | mg of taurine / 100g wet weight | mg of taurine / 1000kcal |
|---|---|---|
| Chicken, 1 to 3d | 167 | 1177 |
| Mouse, 1 to 2d | 125 | 1037 |
| Mouse, 10 to 13 d | 132 | 684 |
| Mouse, 21 to 25d | 226 | 1361 |
| Mouse, 30 to 40d | 201 | 1188 |
| Mouse,150 to 180d | 49 | 290 |
| Quail, >60d | 157 | 901 |
| Quail, 1 to 3d | 151 | 998 |
| Quail, 21 to 40d | 147 | 961 |
| Rabbit | 13.1 | 84 |
| Rabbit, >65d | 30 | 168 |
| Rabbit, 30 to 45d | 3 | 18 |
| Rabbit, ground | 37 | 274 |
| Rabbit, stillborn | 59 | 488 |
| Rat, >60d | 95 | 473 |
| Rat, 1 to 4d | 97 | 1065 |
| Rat, 10 to 13d | 91 | 753 |
| Rat, 21 to 25d | 58 | 364 |
| Rat, 32 to 42d | 67 | 401 |
If the number is in red, the cut contains less than 100mg of taurine per 1000kcal, and so it’s less than the recommendation for a purified diet.
If the number is in yellow, the cut contains between 100mg and 250mg of taurine per 1000kcal, it’s greater than the recommendation for a purified diet but less than the recommendation for a dry diet.
If the number is in light green, the cut contains between 250mg and 425mg of taurine per 1000kcal, it’s greater than the recommendation for a purified and dry diet but it’s less than the recommendation for a canned diet.
If the number is in dark green, the cut contains more than 425mg of taurine per 1000kcal, so it’s greater than the recommendation for a canned diet.
Sources
[1] National Research Council. 2006. Nutrient Requirements of Dogs and Cats. Washington, DC: The National Academies Press.
[2] (2015). Canine and Feline Nutrition (Linda P. Case et al.).
[3] Owens TJ, Fascetti AJ, Calvert CC, Larsen JA. Rabbit Carcasses for Use in Feline Diets: Amino Acid Concentrations in Fresh and Frozen Carcasses With and Without Gastrointestinal Tracts. Front Vet Sci. 2021;7:592753. Published 2021 Jan 21.
[4] Spitze AR, Wong DL, Rogers QR, Fascetti AJ. Taurine concentrations in animal feed ingredients; cooking influences taurine content. J Anim Physiol Anim Nutr (Berl). 2003 Aug;87(7-8):251-62.
[5]Glasgow, A.G., Cave, N., Stanley, L., & Morris, J. (2002). Role of Diet in the Health of the Feline Intestinal Tract and in Inflammatory Bowel Disease
[6] Sturman JA, Messing JM. High dietary taurine effects on feline tissue taurine concentrations and reproductive performance. J Nutr. 1992 Jan;122(1):82-8.
[7] Eric N. Glass, Jack Odle, David H. Baker, Urinary Taurine Excretion as a Function of Taurine Intake in Adult Cats, The Journal of Nutrition, Volume 122, Issue 5, May 1992, Pages 1135–1142.
[8] van Rooijen C, Bosch G, van der Poel AF, Wierenga PA, Alexander L, Hendriks WH. Quantitation of Maillard reaction products in commercially available pet foods. J Agric Food Chem. 2014 Sep 3;62(35):8883-91.
[9] Van Rooijen, C., Bosch, G., Van der Poel, A., Wierenga, P., Alexander, L., & Hendriks, W. (2013). The Maillard reaction and pet food processing: Effects on nutritive value and pet health. Nutrition Research Reviews, 26(2), 130-148.
[10] Hickman MA, Rogers QR, Morris JG. Taurine balance is different in cats fed purified and commercial diets. J Nutr. 1992 Mar;122(3):553-9.
[11] Hickman MA, Rogers QR, Morris JG. Effect of processing on fate of dietary [14C]taurine in cats. J Nutr. 1990 Sep;120(9):995-1000.
[12] Pion PD, Kittleson MD, Rogers QR, Morris JG. Myocardial failure in cats associated with low plasma taurine: a reversible cardiomyopathy. Science. 1987 Aug 14;237(4816):764-8.
[13] Morris, J.G., Rogers, Q.R. and Pacioretty, L.M. (1990), Taurine: an essential nutrient for cats. Journal of Small Animal Practice, 31: 502-509.
Sources for the tables
Spitze AR, Wong DL, Rogers QR, Fascetti AJ. Taurine concentrations in animal feed ingredients; cooking influences taurine content. J Anim Physiol Anim Nutr (Berl). 2003 Aug;87(7-8):251-62.
Laidlaw SA, Grosvenor M, Kopple JD. The taurine content of common foodstuffs. J Parenter Enteral Nutr. 1990;14:183–8
Kerr KR, Kappen KL, Garner LM, Utterback PL, Parsons CM, Swanson KS. Commercially available avian and mammalian whole prey diet items targeted for consumption by managed exotic and domestic pet felines: true metabolizable energy and amino acid digestibility using the precision-fed cecectomized rooster assay. J Anim Sci. 2014 Oct;92(10):4478-85.
Owens TJ, Fascetti AJ, Calvert CC, Larsen JA. Rabbit Carcasses for Use in Feline Diets: Amino Acid Concentrations in Fresh and Frozen Carcasses With and Without Gastrointestinal Tracts. Front Vet Sci. 2021;7:592753. Published 2021 Jan 21.
Sources for the calories in the tables
USDA
CIQUAL
Kerr, K.R., Kappen, K.L., Garner, L.M. and Swanson, K.S. (2014), Commercially available avian and mammalian whole prey diet items targeted for consumption by managed exotic and domestic pet felines: Macronutrient, mineral, and long‐chain fatty acid composition. Zoo Biology, 33: 327-335.