Canned tuna is a staple in many kitchens. It is protein-packed, inexpensive, and can last for several years in your pantry.

Despite these benefits, you may be wondering whether canned tuna is actually healthy and how much is safe to eat.

This article discusses the nutritional content of canned tuna, as well as the potential benefits and downsides of eating it.

Tuna has many varieties. However, overall it is an excellent source of protein that is low in fat and calories.

Whether canned tuna is packed in oil or water can affect its nutritional content. Canned tuna packed in oil tends to be higher in calories and fat than canned tuna packed in water (1, 2).

The following table compares key nutritional information between 1 ounce (about 28 grams) of three different types of tuna: fresh, canned in oil, and canned in water (1, 2, 3).

Overall, canned tuna tends to be higher in sodium than fresh. However, the number of calories and amounts of total fat and saturated fat depend on whether the tuna is packed in oil or water.

Nutrient content can vary between brands based on how tuna is packed, so it is best to check the label.

Canned tuna packed in water may be higher in docosahexaenoic acid (DHA) (4).

DHA is a type of omega-3 fatty acid that is particularly important for brain and eye health (5, 6).

Additionally, both fresh and canned tuna are good sources of several essential vitamins and minerals, including vitamin D, selenium, and iodine (1, 2, 3).

Summary

Both water-packed and oil-packed tuna are good sources of protein and low in saturated fat. However, canned tuna packed in oil tends to be higher in calories and total fat.

There are many benefits of eating canned tuna.

In particular, it is an inexpensive source of protein.

It also keeps for a long time. Some brands can last for 2–5 years in your pantry.

If you are looking to lose weight, canned tuna is a good option because it is low in calories yet high in protein.

Diets that are high in protein have been associated with benefits for weight loss, including increased feelings of fullness and reduced cravings (7, 8).

Despite being low in fat, tuna is still considered a good source of omega-3 fatty acids (1, 2, 9).

Omega-3s are essential dietary fats that are beneficial for heart, eye, and brain health. Fish is considered an important source of these healthy fats in the diet, though you can also get omega-3s from plant foods (10, 11).

As a result, the Dietary Guidelines for Americans currently recommends that adults consume 8 ounces (227 grams) of seafood per week (12).

Eating canned tuna is an easy way to increase the omega-3s in your diet.

The types and amounts of fats can vary depending on the type of canned tuna you choose, so read the labels if you want to compare brands (1, 2, 12).

In addition to healthy fats, canned tuna is also a good source of several vitamins and minerals, especially vitamin D and selenium (1, 2).

Finally, despite being canned, many brands of canned tuna are minimally processed, containing only tuna, water or oil, and salt. Some brands may also add seasonings or broth for extra flavor.

Summary

Canned tuna is an inexpensive, low calorie source of protein and other important nutrients, including omega-3 fatty acids. Some brands can last for 2–5 years in your pantry.

The two main concerns when it comes to tuna are mercury content and sustainability.

There are also some potential downsides to canned tuna specifically, including fat and sodium content and the safety of the can itself.

Mercury and recommended intake of tuna

Mercury is a heavy metal that is often present in fish due to water contamination.

Research has shown that high exposure to mercury can cause serious health problems in humans, including impairments to the central nervous system (13, 14).

Because tuna eat other small fish that may already be contaminated with mercury, this metal may collect and concentrate in tuna. Thus, tuna tends to be higher in mercury than other types of fish like salmon or tilapia (15).

The amount of mercury present depends on the type of tuna.

In general, larger varieties of tuna, like bigeye and albacore, tend to be higher in mercury. On the other hand, smaller tuna fish, like light tuna and skipjack, are lower in mercury (15).

As canned tuna typically contains younger and smaller types of tuna, including light and skipjack, it is typically lower in mercury than frozen or fresh tuna filets (15, 16).

Adults

Studies have shown that people who consume high mercury fish at least once a week have elevated mercury levels and are more likely to experience fatigue (17, 18).

People should limit their intake of canned tuna made from albacore to one 4-ounce (113-gram) serving per week. This is because it is higher in mercury (19).

Instead, try eating low mercury fish like light and skipjack tuna.

Children

Importantly, research has shown mercury exposure is particularly toxic to a developing child’s nervous system. For this reason, caregivers should limit the canned tuna they feed infants and young children (20, 21).

According to the Food and Drug Administration (FDA), children aged 2–10 can have up to 1 ounce (28 grams) of low mercury fish, including light and skipjack canned tuna, two to three times per week (22).

Health authorities have not traditionally recommended fish intake in infants during the first year of life.

However, some research suggests that earlier exposure is associated with a reduced risk of asthma and eczema (23, 24).

However, there are currently no recommendations for canned tuna intake in infants. Therefore, it is best to ask your pediatrician how much canned tuna you can safely introduce to your baby and at what age.

Pregnant or breastfeeding women

The FDA recommends that women who are pregnant or breastfeeding avoid fish high in mercury.

Intake of albacore canned tuna should be no more than 4 ounces (113 grams) per week (22).

However, the FDA says it is safe for pregnant and breastfeeding women to eat low mercury fish, such as canned tuna made from light or skipjack tuna (22).

It recommends two to three 4-ounce (113-gram) servings per week (22).

Sustainability

Because tuna is so popular, there is a growing concern that certain types are being overfished.

Western Pacific blue-eye tuna and Indian Ocean yellowfin tuna may be particularly vulnerable to overfishing (25).

Overfishing is a concern because it affects the ecosystems of oceans and can reduce the food supply for populations that depend on these fish as their primary source of protein (25, 26).

The Marine Stewardship Council (MSC) is an international nonprofit organization that provides independent certification to seafood products harvested with sustainable fishing practices.

For a more sustainable option, look for canned tuna products with the MSC certification on the label.

Other considerations

Canned tuna is often higher in salt than fresh tuna. If your healthcare provider has recommended reducing your salt intake, you may want to choose brands that are lower in salt.

Additionally, if you are trying to lose weight, you may want to choose tuna packed in water rather than oil to avoid consuming excess calories.

As for the can itself, some cans contain bisphenol A (BPA), an industrial chemical used in the lining of cans to help prevent the metal from corroding or breaking (27).

While the effects of BPA are controversial, some people are concerned that regular exposure could negatively affect human health and increase the risk of certain diseases (27, 28).

Due to these potential effects, you may want to choose BPA-free cans. However, scientists need to do more research on BPA and its effects on humans.

Finally, always inspect your cans for any signs of spoilage or contamination, such as sharp dents, cracking, leaking, or bulging.

If your cans have any of these signs or the contents have an off smell or color, it is best to throw them out to avoid potential foodborne illness (29, 30).

Summary

Look for low mercury varieties like light or skipjack tuna, BPA-free packaging, and certification for sustainable fishing practices.

Canned tuna is a nutritious and inexpensive source of protein.

Because cans of tuna last for several years, they are excellent for stocking your pantry with easy lunches and snacks.

Opt for varieties that are sustainable and low in mercury. To do this, choose products made with light or skipjack tuna and make sure they have an MSC certification on the label.