Tuna: Benefits, Nutrition, and Risks

Tuna is one of the most commonly consumed fish in the world. Canned tuna is particularly popular in the U.S. due to it’s affordability, versatility, and ease of storage. There are many types of tuna, but albacore, yellowfin, and skipjack tuna account for most of the tuna consumed worldwide.

Tuna is a nutrient-dense food, providing protein and essential vitamins, minerals, and fatty acids. Eating tuna could benefit health in several ways, from supporting satiety to protecting heart health.

However, there are significant environmental and health concerns related to tuna consumption.

Here’s everything you need to know about tuna, including its potential health benefits, nutrition, and risks.  

Tuna is high in protein, providing over 40 grams (g) per 172-gram can.

Protein supports satiety by slowing down digestion and increasing satiety-inducing hormones such as cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1), which help you feel fuller after eating. Studies show that regularly eating seafood, like tuna, can reduce overall calorie intake, which can promote weight loss. In fact, some research suggests that frequent seafood consumption reduces calorie intake by as much as 9% as compared to other protein sources, like chicken and beef.

Eating high-protein foods, like tuna, can also help you reach and maintain a healthy body composition by preserving muscle mass during weight loss, which is essential for maintaining an optimal resting metabolic rate (RMR), or the calories you burn while at rest.

In addition to being high in protein, tuna is free from carbohydrates and can be included in low-carb and very-low carb diets, such as the ketogenic diet, which have been shown to be effective for boosting weight loss.

Tuna is packed with nutrients, some of which aren’t available in other foods. For example, seafood is the main dietary source of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which play critical roles in health. For example, EPA and DHA are important for nervous system function and have powerful anti-inflammatory effects in the body.

Studies show that a diet high in omega-3s could help reduce the risk of common health conditions, such as heart disease, colorectal cancer, and cognitive decline.

Tuna is also a good source of vitamin D, a fat-soluble nutrient that’s essential for skeletal health, immune function, and more. Vitamin D isn’t found in many foods and eating seafood, like tuna, is one of the best ways to increase your dietary intake of vitamin D. A 172-gram can of tuna covers 17% of your daily needs for vitamin D, making it a good choice for increasing your levels of this critical vitamin.

Eating tuna can also improve your intake of B6, B12, selenium, vitamin E, and magnesium, all of which are essential for health.

Tuna provides a variety of nutrients that support and protect health. For example, tuna’s high protein content and lack of carbs makes it a good choice for people with blood sugar regulation issues, such as those with prediabetes and diabetes. Tuna is carb-free and protein-rich, so it’s an excellent option for a blood sugar-friendly meal or snack choice.

Seafood intake in general has been linked to reduced disease risk and a lower risk of death from all-causes. A 2020 review of 34 meta-analyses found that each 100-gram-per-day increment in fish consumption was associated with an 8% reduced risk of all-cause mortality, a 12% lower risk of coronary heart disease, and a 25% lower risk of heart attack. The review also found that frequent seafood consumption was associated with a reduced risk of depression and liver cancer.

Seafood, like tuna, is a rich source of anti-inflammatory and antioxidant nutrients, such as omega-3 fats, vitamin D, and selenium, which may help protect against disease development by reducing cellular damage, promoting healthy blood vessel function, and protecting against risk factors like high blood pressure.

Tuna is an excellent source of nutrients, providing protein, healthy fats, vitamins, and minerals.

Here’s the nutrition breakdown for a one-can (172 grams) serving of tuna canned in water:

• Calories: 220
• Protein: 40.6 grams (g)
• Fat: 5.11 g
• Carbohydrates: 0 g
• B6: 0.373 milligrams (mg) or 22% of the Daily Value (DV)
• Niacin: 9.98 mg or 62% of the DV
• B12: 2.01 micrograms (mcg) or 84% of the DV
• Vitamin D: 3.44 mcg or 17% of the DV
• Vitamin E: 1.46 mg or 10% of the DV
• Phosphorus: 373 mg or 30% of the DV
• Magnesium: 56.8 mg or 14% of the DV
• Selenium: 113 mcg or 205% of the DV

Tuna is a concentrated source of protein, with one can providing over 40 g of high-quality protein.

In addition to protein, tuna is rich in B vitamins and is especially high in B12, a nutrient needed for red blood cell production, metabolism, neurological function, DNA synthesis, and several other critical processes in the body.

Seafood, like tuna, is one of the few food sources of vitamin D, a fat-soluble nutrient required for bone health, immune function, and the regulation of inflammation. Vitamin D insufficiency and deficiency are extremely common, and incorporating vitamin D-rich foods into your diet could help you maintain healthy levels of this critical vitamin.

Tuna is also a good source of several other vitamins and minerals, including vitamin E, magnesium, and selenium.

Though tuna does provide important nutrients and may support health in several ways, there are environmental and health concerns related to eating tuna.

One of the primary issues associated with tuna consumption is that it’s high in mercury, a heavy metal that’s readily absorbed by the body. If your diet contains mercury-rich foods, this heavy metal can build up over time and harm health in several ways, including damaging neurological and immune health and increasing the risk of heart disease.

Unfortunately, tuna is considered to be one of the primary food sources of mercury worldwide and eating tuna regularly could increase your risk of developing high mercury levels. Keep in mind that because albacore tuna is larger and usually lives longer, it contains around three times more mercury than canned light tuna, which includes smaller species like skipjack. Because of this, the FDA recommends limiting your intake of albacore tuna to no more than once per week and not eating any other seafood for the rest of the week. The FDA recommends keeping your light tuna intake to less than three servings per week.

In addition to mercury, seafood, like tuna, can be contaminated with microplastics. Microplastics are tiny pieces of plastic that pollute marine environments and accumulate in fish. Microplastics contain compounds such as polybrominated diphenyl ethers (PBDE) and bisphenol A (BPA), which are harmful to humans. Though the long-term health effects and toxicity of microplastics is still being studied, experts recommend limiting your intake of seafood known to be high in microplastics, like tuna, to protect your health and reduce your exposure to these harmful substances.

In addition to health concerns, their are environmental issues related to tuna consumption. The increased worldwide demand for fish like tuna has put intense pressure on marine environments and has led to overfishing and destruction of delicate marine habitats.

Though cutting back on your overall seafood consumption is the best way to protect sealife and the environment, choosing more sustainable tuna products can help, too. The Monterey Bay Aquarium Seafood Watch has a database that can help you choose tuna that’s sustainably-caught or farmed and not overfished.

Though tuna can be a healthy choice, it’s important to purchase tuna that’s lower in mercury and to limit your intake of higher-mercury species.

The FDA recommends choosing canned light tuna, including skipjack species, and limiting your intake of albacore and bigeye tuna, which are higher in mercury.

Also, because there are environmental issues linked to tuna consumption, limiting your intake of tuna and choosing other, more environmentally-friendly protein sources, such as sardines, shellfish, and plant-based protein sources like beans, can help reduce your impact on the environment.

If you’d like to enjoy tuna, there are several ways to add it to your diet:

• Top green salads and grain bowls with canned tuna.
• Make a simple tuna salad with canned tuna, chopped celery, and mayonnaise or mustard.
• Try swapping out beef burgers with tuna burgers.
• Enjoy tuna in wraps and sandwiches

Though tuna can be purchased fresh, many people prefer canned tuna due to its versatility, cost, and storage potential.

Canned tuna can be kept in your pantry for up to five years, making it a convenient protein source.

Tuna is a widely consumed fish that’s packed with protein, B vitamins, omega-3 fats, and several other important nutrients.

Though eating more seafood could benefit some aspects of health, such as reducing heart disease risk and supporting healthy body weight maintenance, tuna is high in toxins like mercury and isn’t the most sustainable seafood choice.

If you’d like to incorporate tuna into your diet, it’s important to choose lower-mercury species caught using sustainable methods and to avoid tuna species high in mercury.