How many times have you given your cat a can of tuna when they absolutely refused to eat their kibble? I'll confess something: every time I make a salad or a tuna sandwich, I always give them some. They love that intense flavor , and it's almost impossible to resist their meows.
Lately, we've been told that cats should only eat dry food, but the truth is, that's not the case. If dry food was created during World War II, what did cats eat before then? Whatever they could find: they either hunted rodents or ate what humans threw away. So, can cats eat tuna?
Is tuna good for cats?
The answer is yes, but in moderation . Tuna is a very palatable oily fish for cats and provides high-quality protein and beneficial fats such as omega-3 fatty acids , which support the health of a cat's coat, skin, cardiovascular system, and brain. However, this doesn't mean we can offer them any type of tuna without restraint.
Tuna can contain high levels of mercury and other heavy metals (such as cadmium and lead), which accumulate in large, predatory fish. In high quantities, these metals can be harmful to both cats and humans, causing neurological and kidney damage. Furthermore, it's important to know that tuna alone does NOT provide complete nutrition for cats.
On the other hand, tuna, especially that intended for human consumption, has an unbalanced content of taurine, vitamins, and minerals for a cat. It lacks sufficient vitamin A, calcium, and phosphorus in the right proportions and, at the same time, provides too much fat , which in the long run can contribute to problems such as pancreatitis or worsen kidney disease due to its phosphorus content; in these cases, consult a veterinarian about a diet for cats with chronic kidney failure.
Risks of overusing tuna in a cat's diet
In fact, if a cat ate only tuna, it would likely develop a condition known as feline steatitis (yellow fat disease), caused by a vitamin E deficiency . The main symptoms are fever, tenderness to the touch, pain when moving, swelling of the subcutaneous fat, and loss of appetite. Furthermore, an excess of unsaturated fats contributes to fatty liver disease.
Frequent consumption of tuna can also lead to a vitamin B1 (thiamine) deficiency if it is eaten raw or improperly prepared, as some fish contain enzymes (thiaminases) that destroy this vitamin. This risk explains why cats cannot eat fish . Thiamine deficiency can cause neurological problems such as seizures, incoordination, or even paralysis.
Another major problem is that tuna, especially canned tuna intended for human consumption, often contains a lot of salt and preservatives . Excess sodium can lead to increased blood pressure , kidney and heart strain, which is particularly dangerous for older cats or those with pre-existing health conditions.
Furthermore, a diet based almost exclusively on tuna is very poor in nutrient variety. A diet consisting of only one food causes weakness in cats, as well as in any other animal, including humans. It lacks fiber, a balance between omega-3 and omega-6 fatty acids, and a diversity of vitamins and minerals, which in the medium term translates into serious nutritional deficiencies.
Canned tuna, fresh tuna, and safe ways to serve it
The tuna we usually have at home is almost always canned tuna meant for humans . It's precisely the kind cats like best because of its smell and texture, but it's generally the least recommended to offer regularly. These cans often contain added salt, vegetable oils, or sauces that aren't suitable for a cat's digestive system.
If you're going to give your cat a small treat , the wisest option is to offer canned tuna in its own water, without salt or seasoning , and always in very small amounts and only occasionally. A single can won't significantly affect your cat, but doing so regularly can cause health problems and encourage the animal to reject its regular meals in favor of tuna.
The most nutritionally sound option is fresh or frozen tuna that is then lightly cooked , always boneless, unsalted, and without any seasoning. Freezing it beforehand helps reduce the risk of parasites like anisakis, and gentle cooking eliminates harmful bacteria. It shouldn't be cooked as thoroughly as for one person, but cooked enough to be safe.
There are also commercial cat foods that include tuna or fish among their ingredients. In these cases, the product has been formulated to provide all the nutrients the cat needs, and the fish has undergone controlled cooking processes that inactivate problematic enzymes. This type of food can be part of a balanced diet, as long as fish isn't used as the sole source of protein.
How to use tuna to help a sick or loss of appetite cat
A little tuna won't do him any harm; in fact, when he's very sick and doesn't want to eat anything else, it can be very helpful to mix a little tuna with canned cat food or homemade cat food to stimulate his sense of smell and appetite. This way, we prevent him from suffering from malnutrition while he recovers.
In these cases, it's recommended to use very small amounts , simply to add aroma and flavor to their regular food. The cat shouldn't eat only the tuna and leave the rest; the idea is for the tuna to act as a "hook" to encourage them to eat their entire meal. Once the cat improves and returns to a normal appetite, it's important to gradually reduce the amount of tuna.
If your cat has a poor appetite for several days, loses weight rapidly, or vomits frequently, it's essential to consult your veterinarian . Tuna should not be used to mask a more serious health problem, but rather as a temporary support within a professional treatment plan.
While some cats can eat small amounts of other human foods like cooked chicken or boiled egg, we must always remember that they are obligate carnivores and their diet should be based primarily on animal proteins specifically formulated for their needs, not on leftovers from our meals or highly processed products.
What place should tuna occupy in a cat's diet?
For them to grow properly and stay healthy, it's essential to provide them with a high-quality diet (without grains or low-quality byproducts), or alternatively, a homemade or natural diet, provided it's well-balanced and vetted by a professional. In any case, tuna should be reserved as an occasional treat , never as the basis of their diet.
Ideally, you should rotate the protein source (chicken, turkey, rabbit, beef, other fish in smaller quantities, etc.) so that your cat receives a wide range of nutrients. Fish, including tuna, can be offered occasionally to provide omega-3 fatty acids and a variety of flavors, but not as a continuous primary protein source.
If you decide to include tuna in your cat's diet, remember these key ideas: offer it in small portions , preferably fresh or natural , without salt or sauces, without bones and well cooked, and always within a menu where complete cat food is the main focus.
With controlled amounts, good quality base food, and the supervision of your veterinarian, tuna can be a tasty little treat that your cat can enjoy without compromising its health.