Tuna Fish: Protein Powerhouse or Danger Food?

When you think of health foods, canned tuna might not be the first thing that pops into your mind. Unfortunately, tuna fish has gotten a bad reputation over the years. Despite its multitude of health benefits, it’s considered more of a convenience item or quick dinner option rather than a staple in a nutritious diet.

However, tuna fish is right up there with other healthy types of fish, such as salmon, when it comes to nutrition. It’s low in calories but packs a good amount of protein and heart-healthy omega-3 fatty acids into each serving. It’s also loaded with antioxidants and important micronutrients, giving you all the more reason to make tuna fish a regular part of your diet.

Types of Tuna

What is tuna? It’s a type of saltwater fish that belongs to the same family as mackerel fish and bonito fish. They are members of the Thunnini tribe, which includes 15 different tuna species. The most common types of tuna include:

• Albacore tuna
• Yellowfin (ahi) tuna
• Skipjack tuna
• Bluefin tuna
• Bigeye tuna

The tuna fish size can vary pretty widely between different species; the yellowfin tuna, for example, can be under three pounds while larger varieties like the northern bluefin tuna might weigh up to 1,430 pounds.

Tuna stand out from other types of fish because they are incredibly fast and able to maintain a body temperature above their surroundings. Some types, like the yellowfin tuna, even tend to swim next to dolphins in the Pacific Ocean for protection against predators, such as sharks.

The meat of the tuna fish is often sold frozen, fresh or canned and is widely consumed around the world as a popular ingredient for sandwiches, salads, casseroles and sushi rolls.

Nutrition Facts

The nutrition profile of tuna can vary slightly depending on the type of tuna as well as how it’s prepared. For example, there are more calories in canned tuna in oil compared to the amount of calories in canned tuna in water.

Tuna steak nutrition also tends to be lower in sodium than canned tuna varieties. In general, however, tuna is low in calories but bursting with protein, selenium, niacin and vitamin B12.

One three ounces (85 g) of white tuna canned in water contains:

• Calories: 62
• Total Carbohydrates: 0 g
• Fiber: 0 g
• Sugar: 0 g
• Total Fat: 2.5 g
• Saturated Fat: 0.7 g
• Polyunsaturated Fat: 0.9 g
• Monounsaturated Fat: 0.7 g
• Trans Fat: 0 g
• Protein: 20.1 g
• Cholesterol: 35.7 mg
• Sodium: 320 mg (14% DV*)
• Selenium: 55.8 mcg (101% DV)
• Vitamin B12: 0.994 mcg (41% DV)
• Niacin (vitamin B3): 4.93 mg (31% DV)
• Phosphorus: 184 mg (15% DV)
• Vitamin B6: 0.184 mg (11% DV)
• Magnesium: 28 mg (7% DV)
• Iron: 0.825 mg (5% DV)
• Potassium: 201 mg (4% DV)
• Zinc: 0.408 mg (4% DV)

*Daily Value: Percentages are based on a diet of 2,000 calories a day.

Benefits

1. High in protein

Protein is essential to many aspects of health. It makes up the foundation of your hair, skin, nails and muscles; is crucial for the synthesis of certain enzymes and hormones; and is used for the growth and repair of tissues. Not only that, but a protein deficiency can also have detrimental effects on health, resulting in symptoms like impaired immunity, slow wound healing, low energy levels and an increased appetite.

Tuna meat is loaded with protein — 21 grams in each 3 ounce serving. Combined with just a few other high-protein foods, including even one serving of tuna fish in your diet can help provide your body with the protein that you need.

2. Aids in weight loss

Tuna fish is high in protein but low in calories, making it an excellent addition to a weight loss diet. Thanks to its high protein content, in particular, tuna can help reduce your appetite, ward off cravings and keep you feeling fuller for longer.

One study published in the American Journal of Clinical Nutrition showed that eating a high-protein meal led to greater reductions in levels of ghrelin, the hormone responsible for stimulating hunger, than a high-carb meal. It also slowed gastric emptying, resulting in increased satiety.

Another study from the University of Washington School of Medicine found that upping protein intake by just 15 percent decreased daily caloric intake by 441 calories and caused a significant reduction in body weight and fat mass.

3. Promotes thyroid health

Your thyroid is a butterfly-shaped gland in your neck that’s responsible for regulating your metabolism, producing hormones and maintaining energy levels. Impaired thyroid function can cause serious symptoms, such as changes in weight, body temperature, bowel habits, sexual function and focus.

Tuna nutrition is high-selenium food, with 55.8 mcg in a 3 ounce serving — which is 101 percent Daily Value. It’s a mineral that plays a central role in the health of your thyroid gland. In fact, the thyroid gland is considered the organ with the highest amount of selenium per gram of tissue.

Multiple studies have found that selenium supplementation may be beneficial for conditions like autoimmune thyroiditis, Graves’ disease and hypothyroidism.

4. Boosts brain function

It’s no secret that what you eat can directly impact several aspects of health. In recent years, however, more and more mounting evidence has begun to demonstrate just how crucial your diet may be when it comes to the health of your brain.

Tuna fish is high in several nutrients that have been directly linked to brain health. Niacin, in particular, has been linked to a lower risk of Alzheimer’s disease and age-related decline.

Tuna fish is an excellent omega 3 foods. It’s high in omega-3 fatty acids, including DHA and EPA, which can boost cognitive performance and may be protective against mental health problems like depression.

5. Rich in antioxidants

Antioxidants are compounds that can help neutralize harmful free radicals to protect against cell damage and chronic disease. A higher intake of antioxidants is thought to prevent the development of conditions like heart disease, diabetes, cancer and certain autoimmune disorders.

Tuna is packed with antioxidant-rich selenium, providing 101 percent of the daily recommended value for selenium in each serving. Selenium has antioxidant properties and can help reduce oxidative stress and prevent damage to cells.

According to a study published in the World Journal of Biological Chemistry, tuna is also high in a selenium-containing compound called selenoneine, which fights off free radicals and could even protect against chronic disease and aging.

6. Reduces Inflammation

Inflammation is a normal response by the immune system that can help fight off foreign invaders and protect the body from illness and infection. Long-term inflammation, on the other hand, has actually been tied to an increased risk of certain diseases like cancer and heart disease.

Tuna is rich in omega-3 fatty acids, or fish oil, which may be able to alleviate inflammation and reduce the risk of disease. In fact, one of the primary ways that fish oil benefits health is through its potent anti-inflammatory properties, and multiple studies have shown that it could be therapeutic for autoimmune conditions like Crohn’s disease, lupus, rheumatoid arthritis and psoriasis.

Potential Downsides

Despite the multitude of potential tuna fish benefits, there are certain downsides that should be considered as well.

As with nearly any type of fish, the mercury content should be taken into account. Mercury poisoning can cause symptoms like memory problems, numbness, shaking and double vision. Certain types of tuna are higher in mercury than others.

A 2024 study by a group of international scientists showed that high level of mercury are still found in tuna; it also noted that this hasn’t altered much at all over the past 50 years.

Canned white tuna, for instance, contains nearly three times the amount of mercury as skipjack tuna, which is commonly found in canned light tuna.

The FDA recommends that children and pregnant women limit fish consumption to about 12 ounces per week and steer clear of fish with high levels of mercury, such as king mackerel, bigeye tuna, tilefish and swordfish, to prevent adverse effects on health.

If you’re ordering tuna sushi, you should also skip the Hon Maguro, or Atlantic bluefin tuna. Although this type of tuna is a staple in sushi restaurants, it lands on the list of fish you should never eat because it’s been overfished to the brink of extinction. However, because it’s in such high demand, it remains a target of commercial fishing as its population continues to dwindle.

If you’re consuming canned tuna, you should also consider the sodium content. Like most canned foods, canned tuna is generally high in sodium, which may be linked to increased levels of blood pressure. Tuna in water is the best canned tuna if you’re looking to cut back on your sodium intake. Rinsing off canned tuna fish can also reduce the sodium content by up to 80 percent as well.

Tuna vs. Salmon

Tuna and salmon may be considered two of the most commonly consumed types of fish, but there are plenty of differences that set them apart.

Tuna has a more mild, less fishy taste while salmon is generally more rich, juicy and tender. Both types of fish can be cooked similarly and are available in fresh and canned forms.

If you compare the cooked salmon and tuna fish nutrition profile per ounce, tuna is slightly higher in protein and lower in calories. It also contains a higher amount of certain micronutrients, such as niacin, phosphorus and vitamin B12. Salmon, on the other hand, is higher in folate and healthy fats, including omega-3 fatty acids.

That being said, both are easy to find, full of beneficial nutrients and can make valuable additions to a balanced meal. Enjoy a serving or two of both per week to maximize the health benefits of your diet.

Where to Find Tuna

Widely available at most grocery stores and supermarkets, finding canned tuna is easier than ever. You’ll typically find tuna in the same aisle as other canned fish, such as salmon and sardines.

However, there are other types of tuna to eat besides canned tuna. You can also often find frozen tuna steaks at most grocery stores, or you can find them fresh if you stop by your local fish market.

The tuna fish price can vary based on the type of tuna you’re purchasing. Canned tuna is generally the most affordable option while yellowfin tuna ranks among the most expensive, clocking in between $8–$15 per pound.

Recipes

Although many people think of tuna as a last resort dinner option when the fridge is starting to get empty, it can be so much more than that. You can easily use tuna canned to make a delicious tuna fish sandwich or tuna fish salad.

Tuna is also a popular ingredient in sushi rolls, pasta dishes, soups, poke bowls and, of course, tuna fish casserole. Tuna steaks can also be seasoned and grilled, seared or baked and served alongside your favorite side dishes.

Precautions

If you have an allergy to fish, you should avoid tuna as well as other types of seafood. Additionally, if you experience any food allergy symptoms after eating tuna, discontinue use and talk to your doctor.

Stick to tuna fish varieties that are low in mercury, and avoid high-mercury fish, such as bluefin tuna and bigeye tuna. Children and pregnant women should keep fish intake in moderation to minimize mercury exposure.

You should also avoid Atlantic bluefin tuna, which may have a negative impact on both the environment and your health because it is overfished and often farm-raised. Stick to wild types of tuna that are caught using the Pacific troll or pole and line methods.

Conclusions

• Tuna is a type of saltwater fish that belongs to the same family as mackerels and bonito fish. The tuna size can vary widely, from under three pounds to over 1,400 pounds based on the species of fish.
• Tuna is low in calories but high in protein, niacin, selenium and vitamin B12.
• Adding tuna to your diet can improve weight loss, reduce inflammation, boost brain function and promote thyroid health.
• Certain types of tuna are high in mercury, overfished and often farm-raised, placing them on the list of health foods you should never eat. For this reason, you should avoid Atlantic bluefin tuna and select healthier varieties like skipjack tuna.
• Try incorporating tuna into your diet by adding it to your next casserole, salad or tuna sandwich and enjoy the many health benefits that it has to offer.