Taurine for Cats: Why Every Dry Cat Food Contains It

Taurine is an amino acid that cats cannot make enough of on their own, so it has to come from food. Every cat food labeled complete and balanced must meet a taurine minimum, and 146 of the 149 dry foods on Pettings list taurine as an added ingredient.

What Taurine Is

Most amino acids are building blocks of protein. Taurine is different: the body does not build it into proteins but uses it on its own, and it is found in high amounts in the heart and the retina, the light-sensing layer at the back of the eye. Many animals make enough taurine from two other amino acids, methionine and cysteine. Cats make very little this way, which is why it is called an essential nutrient for cats.

Cats also use taurine in digestion. Bile acids, which help digest fat, are paired with another molecule before they are released. Many animals can use either glycine or taurine for this. A 1976 study found that cats use taurine almost exclusively, so some taurine is lost with every meal.

What the Research Found

The early evidence came from controlled feeding studies. In one, cats fed a taurine-free diet based on casein, a milk protein, lost retinal function: a test of the retina's electrical response could no longer detect any signal. Cats given taurine kept normal retinal function. Cats given methionine or cysteine instead did not. That result is the main reason taurine is treated as a nutrient cats need from their diet, not one they can make.

The heart came next. In 1987, veterinary researchers linked low blood taurine in cats to dilated cardiomyopathy, a disease in which the heart muscle thins and the heart enlarges. A 1992 study of cats with the disease found low taurine and a diet history that could explain it in most of them. A companion study gave the cats taurine and reported that more than half improved; it compared them with earlier cases rather than a control group.

Tufts University's veterinary nutrition team sums up the result: cats fed too little taurine can go blind from retinal degeneration, and their hearts can enlarge and stop pumping properly. This is why all cat foods should include taurine.

How Much Cat Food Must Contain

AAFCO, the organization that writes the model rules for US pet food, sets a minimum of 0.10% taurine on a dry matter basis for dry food and 0.20% for canned food. Dry matter basis means the share once the water is taken out on paper (our label guide shows how).

Meat, fish and organs contain taurine naturally, but the amount left after cooking and storage varies. That is why most makers add it. On Pettings, 146 of 149 foods list taurine in their ingredients. The three that do not are all Orijen recipes (Original Cat, Kitten and Guardian 8). The first ingredients of Orijen Original Cat are chicken, turkey, whole herring, turkey giblets and salmon: whole meats and organs that carry taurine on their own. A food can meet the minimum either way. The ingredient list tells you whether taurine was added, not how much the food contains.

Reading the Label for Taurine

Some makers list taurine in the guaranteed analysis as a minimum percentage. Others do not, because only protein, fat, fiber and moisture are required there. When taurine is listed, that number is a promise the maker can be held to.

When it is not listed, look at the nutritional adequacy statement. "Complete and balanced" for your cat's life stage means the food meets the AAFCO profile, and that profile includes taurine. A food labeled "for intermittent or supplemental feeding only" does not have to meet it.

Taurine does not change our scores. Our Ingredient score rates each ingredient on what it is, and vitamins and supplements like taurine count with the rest of the list after the first five.

When Cats Still Fall Short

Problems are now rare in cats eating a complete and balanced cat food. They show up mostly when the diet is not built for cats. Dog food is not formulated to the cat's taurine needs, and Tufts notes that cats need a carefully formulated diet for this reason. Homemade diets carry the same risk. The total taurine in a recipe is not the whole story either: other ingredients can change how much of it the cat absorbs.

If your cat has a heart condition or changes in vision, ask your veterinarian about diet and taurine. Do not change food or add supplements on your own.

What to Check on the Bag

• The adequacy statement: complete and balanced for your cat's life stage.
• The guaranteed analysis: a taurine minimum, if the maker lists one.
• The ingredient list: taurine as an added ingredient, usually near the vitamins and minerals at the end.

Related: Is Grain-Free Cat Food Bad for Cats? covers the FDA's diet and heart disease reports, which were about dogs.

Sources

• Rabin B, Nicolosi RJ, Hayes KC (1976). "Dietary influence on bile acid conjugation in the cat". Journal of Nutrition 106(9):1241-6.
• Pion PD, Kittleson MD, Rogers QR, Morris JG (1987). "Myocardial failure in cats associated with low plasma taurine: a reversible cardiomyopathy". Science 237(4816):764-8.
• Berson EL, Hayes KC, Rabin AR, Schmidt SY, Watson G (1976). "Retinal degeneration in cats fed casein. II. Supplementation with methionine, cysteine, or taurine". Investigative Ophthalmology 15(1):52-8.
• Pion PD, Kittleson MD, Thomas WP, Skiles ML, Rogers QR (1992). "Clinical findings in cats with dilated cardiomyopathy and relationship of findings to taurine deficiency". JAVMA 201(2):267-74.
• Pion PD, Kittleson MD, Thomas WP, Delellis LA, Rogers QR (1992). "Response of cats with dilated cardiomyopathy to taurine supplementation". JAVMA 201(2):275-84.
• Linder DE, Tufts Petfoodology (2018). "Cats Are Not Small Dogs: Unique Nutritional Needs of Cats".
• AAFCO Cat Food Nutrient Profiles (taurine minimums, dry matter basis), AAFCO Official Publication.
• Food figures from the Pettings food pages, copied from the makers' labels.

Scores describe what the label says. They are not medical advice.