Canned Tuna for Cats. Is it Really That Bad?


Cats love tuna. The smell and taste of tuna is almost irresistible to cats. Whether it comes from a can or the pouch, cats can’t seem to get enough. However, behind tuna’s popularity lies concerns about its nutritional value and potential health risks. While tuna tastes great to cats and makes an easy meal or snack, is it really good for cats to eat tuna regularly or in large amounts?

This article explores the pros and cons of feeding tuna to cats. We’ll look at tuna’s nutritional profile, benefits, risks, how much tuna is safe, best practices for serving, signs of overexposure, alternatives, and when to avoid tuna altogether. The goal is to provide cat owners a comprehensive understanding of tuna’s place in a cat’s diet.

Nutritional Profile of Tuna

Tuna is known for being a high protein food, with a 3 ounce can containing about 7-8 grams of protein (source). However, tuna is relatively low in many other nutrients that cats require in their diet.

For example, tuna is low in vitamin E, an essential vitamin for immune and nervous system function in cats (source). It also provides minimal amounts of calcium and magnesium, minerals important for bone health and enzyme function (source). While tuna can contribute protein to a cat’s diet, it lacks optimal levels of other key nutrients cats need.

Benefits of Tuna for Cats

Tuna can be a beneficial addition to a cat’s diet in moderation. Here are some of the main benefits of tuna for cats:

Tuna is a highly palatable source of protein for cats. Cats are obligate carnivores and require a high protein diet, with protein making up about 40% of their daily caloric intake [1]. Tuna is an excellent source of protein, providing amino acids that help maintain muscle mass.

The moist texture of tuna makes it good for hydration. Cats have a low thirst drive and can be prone to dehydration. The high moisture content in canned tuna can help increase their water intake.

Risks of Too Much Tuna

While tuna can be a healthy part of a cat’s diet in moderation, too much tuna can pose some risks. The primary risk associated with feeding cats too much tuna is mercury exposure. Tuna contains higher levels of mercury than other types of fish and seafood. When cats consume high amounts of tuna, the mercury can accumulate in their bodies over time and lead to mercury poisoning. According to research from Hill’s Pet Nutrition, the mercury in tuna can cause neurological damage in cats if they consume too much.

In addition to mercury risks, feeding cats too much tuna can lead to nutritional deficiencies. Tuna is high in protein but lacks proper levels of some essential vitamins and minerals that cats need. According to Wag Walking, tuna is deficient in nutrients like vitamin E, niacin, magnesium, and calcium. Feeding cats too much tuna, without supplementing with other foods, can therefore lead to deficiencies in these key nutrients over time.

To reduce the risks of mercury exposure and nutritional deficiencies, it’s recommended to limit tuna to no more than 2-3 times per week for cats. Feeding tuna in moderation, as an occasional treat, and offering a balanced diet alongside tuna can allow cats to enjoy the benefits of tuna safely.

How Much Tuna is Safe?

Up to 3 ounces of tuna per week is generally considered safe for cats according to experts. However, the amount of tuna that is safe depends on the type of tuna being fed. White tuna tends to have lower levels of mercury than albacore tuna, so cats can eat more white tuna safely.

According to this source, one teaspoon of tuna a few times a week, or about half a can per month is considered safe for cats. For albacore tuna which contains higher mercury levels, less tuna should be fed. No more than 1 ounce of albacore tuna per week is recommended.

It’s important to limit tuna intake and feed it alongside other foods, rather than as a steady diet. Feeding too much can lead to nutritional imbalances and mercury exposure over time. Following the recommended safe amounts allows cats to enjoy tuna as an occasional treat without risk.

Best Practices for Feeding Tuna

Tuna can be a healthy treat for cats in moderation. But it’s important not to feed too much tuna or rely on it as a staple in your cat’s diet. Here are some best practices when feeding tuna to cats:

Serve tuna as an occasional treat or meal topper, not a staple. Tuna lacks essential vitamins and minerals that cats need for balanced nutrition. Feeding too much can lead to malnutrition over time. Limit tuna to no more than 10% of your cat’s total daily calories.

Balance tuna with other foods to meet nutritional needs. Pair tuna treats with your cat’s normal high-quality cat food, which provides complete and balanced nutrition. Or mix a small spoonful of tuna into their regular meals for extra flavor.

Look for tuna canned in water rather than oil, and go for low-sodium options. While tuna packed in oil has more calories, the fats are not healthy for cats long-term. And too much salty canned tuna can cause dehydration.

Avoid tuna packaged for humans. Human-grade canned tuna often contains added salt, oil, and preservatives that are unhealthy for cats. Look for tuna products specifically formulated for cats.

Ask your vet about appropriate tuna feeding guidelines for your cat. Factors like age, weight, activity level, and any health conditions can impact how much tuna is safe in your individual cat’s diet.

Signs of Tuna Overexposure

Eating too much tuna can cause a range of concerning symptoms in cats. The most serious issue is mercury poisoning, which occurs because tuna contains high levels of mercury. According to WebMD, symptoms of mercury poisoning include “dizziness and loss of coordination and balance”. The Daily Paws adds that other signs of mercury toxicity are “ataxia (drunken/wobbly gait), tremors or seizures, and abnormal pupil size.”

Aside from mercury, an exclusive diet of tuna can cause other nutrient deficiencies over time. According to Hill’s Pet Nutrition, tuna lacks sufficient levels of nutrients like calcium, magnesium, vitamin E and vitamin C that are essential for cats. Long-term nutritional imbalance can lead to symptoms like muscle weakness, tiredness, fragile bones, and joint problems.

Pet owners should monitor their cat closely for any of these symptoms if tuna has been a large part of their diet. Seeking early veterinary advice is recommended if any concerning signs are noticed.

Alternatives to Tuna

While tuna can be an appealing cat food option due to its taste and texture, it’s best not to feed tuna as the sole or primary protein source in your cat’s diet. There are many other nutritious options that can provide a balanced array of nutrients.

One great alternative to tuna is other fish varieties like salmon, mackerel, and sardines. These oily fish provide omega-3 fatty acids, which are important for skin and coat health. Many cats love the taste of salmon or mackerel. Just be sure to look for fish packed in water without added salt.

You can also rotate in high-quality commercial cat foods, whether wet, canned, or dry varieties. Look for foods formulated specifically for your cat’s life stage and activity level. Fortified cat foods will supply balanced nutrition including vitamins, minerals, and amino acids. Ask your veterinarian for specific diet recommendations.

By incorporating a variety of fish, commercial cat foods, and other protein sources, you can provide a nutritionally balanced diet without having to rely too heavily on tuna. Just gradually transition to the new foods over time. This will help satisfy your cat’s cravings while optimizing their dietary health.

When to Avoid Tuna

There are certain times when tuna should be completely avoided for cats. The two main instances are for kittens and for cats with kidney disease or hyperthyroidism.

Kittens have much greater nutritional needs as they grow, so the limited nutrients in tuna are insufficient. Pregnant and nursing cats also require greater nutrient density. Kittens should only eat a complete and balanced kitten formula. Tuna lacks the vitamins, minerals, and overall nutrition that kittens require for healthy development 1.

For cats with kidney disease or hyperthyroidism, tuna’s high levels of mercury and sodium can worsen these conditions. Kidney disease makes it difficult for cats to eliminate excess toxins and nutrients efficiently. Hyperthyroid cats struggle to maintain proper electrolyte balance. It’s best to avoid tuna and feed a veterinary therapeutic diet formulated for kidney or thyroid disease 2.


In summary, tuna can be a healthy treat for cats in moderation but does carry some risks if fed improperly or in excess. The main points are:

  • Tuna is high in protein and omega-3s but also very high in sodium.
  • Small amounts of tuna are safe for cats and can provide healthy nutrients.
  • Feeding too much or too often can cause mercury poisoning and nutritional imbalances.
  • Limit tuna to no more than 1-2 times a week and just a tablespoon or two each time.
  • Look for low-sodium varieties packed in water for less risk.
  • Watch for signs of addiction or illness if feeding tuna.
  • Rotate or mix with other foods to ensure a balanced feline diet.
  • Talk to your vet about the appropriate amount of tuna to feed your cat.

With some precautions, tuna can be a healthy occasional treat that most cats enjoy. Feed tuna in moderation along with a nutritionally balanced diet for your feline friend.

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