Taurine in Cats: Why It Is Essential and Which Foods Contain It

There is one word you will find on almost every cat food label: taurine. Most owners read it and move on, yet taurine is one of the best-documented topics in feline nutrition and the clearest example of why a cat cannot be fed like a "small dog".

This guide covers what taurine is, why it is considered essential for cats, which foods contain it, how cooking and food type affect the amount of taurine, which feeding patterns are discussed as carrying a deficiency risk, and where coenzyme Q10, another frequently asked-about ingredient, fits into feline nutrition.

One note before starting: this is a nutrition guide, not a diagnostic guide. An assessment of your cat's taurine status, heart or eyes can only be made through a veterinary examination.

What is taurine?

Taurine is a sulphur-containing amino acid. Unlike the amino acids that are the building blocks of proteins, it is not incorporated into proteins; it is found free in the body, in particularly high amounts in heart muscle, in the retina of the eye, in muscle and in nerve tissue.

Taurine has a wide range of roles in the body. It is used to conjugate bile acids and so in the digestion of fats. It plays a role in the normal structure of the light-sensitive cells of the retina and in the normal functioning of heart muscle. It also contributes to fluid balance within cells and to reproduction and growth.

Why is taurine essential for cats?

Many mammals can make taurine themselves from the sulphur amino acids methionine and cysteine. In cats, the enzymes involved in this pathway work at low activity, so the taurine a cat produces is not enough to meet its needs.

The second reason relates to digestion. Dogs and humans can use glycine as well as taurine to conjugate bile acids. Cats use only taurine for this. Because part of the taurine that passes into the gut with bile is not recovered, a cat loses taurine every day, and that loss has to be covered by the diet.

Taken together, the conclusion is clear: the literature defines taurine as an essential amino acid that cats must obtain from their diet. It is one of the most concrete signs that the cat is an obligate carnivore.

Which conditions has taurine deficiency been associated with?

The importance of taurine for cats became clear through studies in the 1970s and 1980s. A progressive degeneration of the centre of the retina was described in cats fed taurine-free diets. In the following years, low blood taurine levels were associated with dilated cardiomyopathy, a picture in which the heart muscle enlarges and loses its contractile strength. The literature also reports that taurine deficiency is associated with growth and reproductive problems in kittens.

These findings changed how cat food is made. Today, foods produced as complete and balanced for cats are formulated to meet set minimum taurine values, and conditions linked to taurine deficiency are therefore seen far less often than in the past.

The point to underline here is this: these conditions can progress silently for a long time and cannot be told apart by looking from the outside. If you notice any change in your cat's vision, willingness to move, breathing or appetite, do not try to guess the cause at home; see your veterinarian. Where needed, the vet will plan assessments such as measuring blood taurine levels and examining the eyes and heart. What to do for a cat in which deficiency is suspected is also decided by the veterinarian.

Which foods contain taurine?

Taurine is found almost exclusively in animal tissues. Plant foods contain either none or negligible amounts. The foods the literature highlights as relatively rich are:

Shellfish: mussels and similar shellfish are among the foods with the highest taurine content.
Fish: a good source, although it varies by species.
Dark poultry meat: dark muscle such as chicken and turkey thigh contains more taurine than breast meat.
Heart: heart muscle is one of the tissues rich in taurine.
Red meat: contains taurine; the amount varies with the tissue.

The prey of a hunting cat in the wild is rich in taurine. The taurine of a cat living at home comes largely from its food.

Comparing these sources in a single table makes label reading easier:

Food group	Position regarding taurine	Note
Shellfish (mussels and similar)	Named among the richest groups in the literature	Not a source used regularly in a home kitchen
Fish	Described as a good source	Varies by species and tissue
Dark poultry meat (thigh)	Higher than breast meat	Dark muscle tissue is denser in taurine
Heart	Among the rich tissues	Stands out within the organ meat group
Red meat	Contains taurine	The amount varies with the tissue
Plant foods	None, or negligible amounts	This is the basic difference behind taurine being considered essential for cats

The table is not a meal plan or an amount recommendation; make every decision about your cat's diet together with your veterinarian.

How do cooking and food type affect the amount of taurine?

Taurine is water-soluble. The literature has shown that boiling meat in water moves a considerable share of its taurine into the cooking water. So the assumption "there is meat, so there is taurine" does not always hold for home-cooked food.

Food type also makes a difference. The heat processing of canned (wet) food can lead to changes in the gut that reduce the recovery of taurine. For this reason AAFCO and FEDIAF recommend, on a dry matter basis, at least 0.10% taurine in dry food and at least 0.20% in canned food for cats. In other words, the minimum set for wet food is twice that for dry food.

What to look for on a label is the statement "complete and balanced for cats". A food carrying this statement is formulated to meet the whole of the daily diet. Treats or products labelled "complementary" do not on their own take the place of the daily diet.

Which feeding patterns are discussed as a taurine deficiency risk?

The common thread among cats reported in the literature with taurine deficiency is that the cat had been fed, over a long period, a diet not formulated for cats:

Dog food over a long period: dog foods are not made to a cat's requirements.
Unformulated home-made food: especially recipes based on boiled meat, rice and vegetables that have not been calculated by a nutritionist or veterinarian.
Vegan or vegetarian diets: because taurine is not found in plant foods, these diets carry a particular risk for cats.
Unbalanced raw feeding: deficiency has been reported in the literature when muscle meat is given on its own or the recipe is not balanced.

If your cat is fed in one of these ways, or you are thinking of moving to home-made food, review the recipe with your veterinarian. Whether a home-prepared diet is complete for a cat can only be known by calculating it. You can find more on reviewing the diet of an ageing cat in our guide to senior cat care, and on nutrition in the kitten period in our kitten care guide.

What is coenzyme Q10 and where does it fit in feline nutrition?

Another ingredient often asked about alongside taurine is coenzyme Q10 (ubiquinone). Q10 works in the mitochondria, the cell's power plants, as part of the chain that extracts energy from nutrients. It is also a component of the antioxidant system that protects cell membranes against oxidative stress.

It differs from taurine in one important way: the body can make Q10 itself, and no minimum requirement has been set for cats. So Q10 is not considered an essential nutrient in the way taurine is. Animal tissues such as heart, liver, muscle meat and oily fish contain Q10.

The literature shows that Q10 has been studied from various angles in humans and some animal species, but research in cats is limited. So if you are considering giving your cat a product containing Q10, talk to your veterinarian about whether it suits your cat's situation. For a similar look at fatty acids in cats, see our article on salmon oil and omega-3 for cats.

What does it mean when taurine and Q10 appear on a product's ingredient list?

Taurine and Q10 often appear on the ingredient lists of supplements and complementary products. For example, Nutrasion L-Glutamine Cat Digestive Supplement is a digestive product prepared for cats aged 7 and over, and its ingredient list includes coenzyme Q10 and taurine alongside L-Glutamine.

One distinction needs to be made clearly here: an ingredient appearing on a list does not mean that the product is a source that meets a cat's taurine requirement. A cat's daily taurine comes from a food produced as complete and balanced for cats. Supplements are used to complement the diet. If you have any concern about your cat's heart, eyes or diet, talk to your veterinarian before choosing a product. For a general framework comparing vitamin and supplement forms, see our article on vitamin drops for cats.

Quick summary

Taurine is an essential amino acid for cats; a cat cannot make enough of it and loses some every day through bile.
Taurine is found almost only in animal tissues; shellfish, fish, dark poultry meat and heart are relatively rich sources.
Boiling moves part of the taurine into the cooking water; the minimum taurine value for wet food is twice that for dry food.
Complete and balanced cat food is formulated to contain taurine; dog food, unformulated home-made food and vegan diets are mentioned in the literature as risks.
Coenzyme Q10 is not essential; research in cats is limited.
Conditions associated with taurine deficiency cannot be recognised at home; the assessment is the veterinarian's job.

Frequently asked questions

Can't cats make taurine in their own bodies?

Only in very limited amounts. Because the enzymes involved in making taurine work at low activity in cats, and because cats use only taurine to conjugate bile acids, the literature defines taurine as an essential amino acid that cats must obtain from their diet.

Which foods contain the most taurine?

Taurine is found almost exclusively in animal tissues. Mussels and similar shellfish, fish, dark poultry meat and muscle tissue such as heart are relatively rich sources. Plant foods contain either no taurine or negligible amounts.

Does a cat eating a complete and balanced cat food need extra taurine?

Foods produced as complete and balanced for cats are formulated to contain taurine; AAFCO and FEDIAF set separate minimum taurine values for dry and canned foods. If you have a question about whether a healthy cat on such a food needs extra taurine, your veterinarian assesses it.

Is feeding a cat dog food a problem for taurine?

Dog foods are not formulated to a cat's nutrient requirements, and their taurine content may not meet the level set for cats. The literature reports taurine deficiency in cats fed dog food, poorly formulated home-made diets or vegan diets over long periods. A cat's main diet should be a complete and balanced food made for cats.

How do I know if my cat is taurine deficient?

It cannot be worked out at home. Eye and heart changes associated with taurine deficiency can progress silently for a long time. The assessment is made by a veterinarian; where needed, blood taurine levels are measured and eye and heart examinations are carried out. If you notice any change in vision, willingness to move or breathing, see your veterinarian without delay.

Is coenzyme Q10 essential for cats?

No. Coenzyme Q10 is a compound the body can produce, and no minimum requirement has been set for cats. It plays a role in the cell's energy production and in the antioxidant system. Research on Q10 in cats is limited; if you are considering giving your cat a product containing Q10, consult your veterinarian.

Sources

Hayes KC, Carey RE, Schmidt SY. Retinal degeneration associated with taurine deficiency in the cat. Science, 1975.
Knopf K, Sturman JA, Armstrong M, Hayes KC. Taurine: an essential nutrient for the cat. Journal of Nutrition, 1978.
Pion PD, Kittleson MD, Rogers QR, Morris JG. Myocardial failure in cats associated with low plasma taurine. Science, 1987.
Spitze AR, Wong DL, Rogers QR, Fascetti AJ. Taurine concentrations in animal feed ingredients; cooking influences taurine content. Journal of Animal Physiology and Animal Nutrition, 2003.
National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, 2006.
FEDIAF. Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs, 2021.
Bentinger M, Brismar K, Dallner G. The antioxidant role of coenzyme Q. Mitochondrion, 2007.

Disclaimer: This article is for information only; consult your veterinarian for diagnosis and treatment. Supplements are not medicines and do not replace a veterinary examination.