Can You Eat Tuna Every Day? Exploring The Safety Of Eating Tuna

Tuna fish is a popular lunch staple for people trying to follow a high-protein diet, or you might enjoy a fresh tuna steak or tuna sushi for dinner to reap the health benefits of tuna while enjoying the taste.

Eating a can of tuna every day can be a convenient and easy way to have a healthy lunch, but is it bad to eat tuna every day? Can you eat tuna every day? Do the tuna health benefits outweigh the risks of eating tuna every day?

Although tuna nutrition facts are impressive, and there can certainly be health benefits of eating tuna frequently, there are also concerns about mercury in tuna fish and whether it is safe to eat tuna every day.

In this guide to tuna nutrition and safety, we will discuss tuna nutrition facts, tuna health benefits, and tuna mercury concentrations, and then focus on answering the questions: Can you eat tuna every day, or is eating tuna every day bad for you?

We will look at: 

• Is Tuna Good for You?
• Does Canned Tuna Have Mercury?
• Can You Eat Tuna Every Day?

Let’s get started!

Is Tuna Good for You?

Before we answer the question: “Can you eat tuna every day?“ let’s look at the health benefits of tuna and nutrition facts about tuna to get a sense of whether tuna is good for you.

It’s actually difficult to look at tuna nutrition facts because there are all sorts of types of tuna, from fresh tuna steaks to canned tuna, and even within these two fairly disparate tuna forms, there are different species of tuna fish, which change the tuna nutrition facts.

For example, canned light tuna packed in water is low in calories and contains almost no fat, whereas fresh tuna steak is a fatty fish rich in polyunsaturated fats and provides minerals like iron.

In general, tuna is considered healthy because it is high in protein and provides some vitamins and minerals.

For example, a 3-ounce portion (85 g) of light canned tuna in water without salt added has about 100 calories and 22 grams of protein, according to the USDA.

Fresh tuna or canned packed in oil vs. water provides omega-3 fatty acids that reduce inflammation and can improve heart health and brain health.

Note that some canned tuna is very high in sodium. The highest sodium tuna fish is generally the seasoned or flavored tuna packets or tuna pouches for to-go tuna snacks. 

Make sure to look at the nutrition label on tuna if you are following a low-sodium diet or want the healthiest tuna option.

Does Canned Tuna Have Mercury?

So, is it safe to eat tuna every day due to its mercury content?

Although we have covered that there are health benefits of tuna fish and tuna nutrition facts are generally overwhelmingly positive for most diets, we now have to look at the risks of eating tuna every day by focusing on tuna from mercury content.

Before we answer the questions: Does canned tuna have mercury, or is it bad to eat tuna every day, it is helpful to understand why some fish and seafood have mercury in them in the first place.

Volcanic eruptions and industrial activity both emit mercury or leech mercury into the ocean waters. 

Mercury is a heavy metal, and it builds up in an organism because it is not excreted through urine or feces. 

Just as mercury toxicity can occur in humans, and we have to be careful of mercury contamination, mercury builds up in marine life, such as fish, seafood, seaweed, and other sea vegetables and plankton.

Unfortunately, tuna contains more mercury than many other popular fish and seafood that people eat, such as salmon, tilapia, cod, flounder, oysters, scallops, lobster, and shrimp.

The reason that tuna mercury levels are higher than some of these other common seafood choices is that tuna eat smaller fish because they are considered tertiary predators.

This means that tuna feed on fish that have eaten other marine plant life or even other fish, already accumulating mercury in their own bodies.

Then, when the tuna eat these mercury-containing fish, they get a concentrated dose of mercury since mercury is not readily excreted from the organism’s body.

Thus, mercury levels build up in tuna over time.

When we eat canned tuna or fresh tuna, the flesh that we are eating in the tuna fish is contaminated with this mercury buildup.

Again, because the tuna have eaten other fish that already have mercury as well as being surrounded by mercury in the ocean waters, tuna mercury content is generally higher than certain other fish that feed on plant life.

So, how much mercury is in tuna?

Ultimately, the amount of mercury in tuna fish depends on the tuna species and sometimes how the tuna is prepared, where it is sourced from (farmed vs. fresh and which part of the world, etc.).

The following table shows the approximate average amount of mercury in tuna of different types based on data from the FDA.

Note that seafood mercury concentrations are measured in parts per million (ppm) or micrograms (mcg).

The micrograms of mercury in tuna tell you the absolute amount of mercury in tuna of a given serving size, whereas the parts per million tuna mercury concentration gives you a sense of how “concentrated“ the mercury in tuna fish is based on the overall volume.

Can You Eat Tuna Every Day?

So, it can be seen that tuna has mercury, but is the amount of mercury in tuna safe or dangerous? Is it safe to eat tuna every day?

Consuming too much mercury can lead to heavy metal toxicity, cognitive impairment, depression, impaired brain function, compromised cardiovascular health, and may impact organs and tissues such as your liver, kidneys, bones, reproductive organs, and brain.

According to the US Environmental Protection Agency (EPA), the reference dose of mercury, which refers to the maximum safe dose of mercury, is 0.045 mcg of mercury per pound (0.1 mcg per kg) of body weight per day for adults.

Essentially, this mercury safety limit is based on body weight/body size, so determining how much tuna is safe to eat per day, or whether it is even safe to eat today every day, will depend on your body weight.

The following table multiplies out the maximum daily mercury intake for several body weights to get a sense of maximum safe mercury limits and how much tuna you can eat per day.

Remember that different species of tuna have different concentrations of mercury, as shown in the tuna mercury amounts table above, so even for some larger individuals, a single 3-ounce can of some tuna may have too much mercury for you to safely eat tuna every day.

Generally, the worst tuna to eat every day in terms of the highest mercury tuna types include albacore tuna, yellowfin tuna, and bigeye tuna.

Also note that some cans of tuna are larger than 3 ounces, so you need to pay attention to tuna serving sizes for daily tuna consumption.

Studies suggest that regularly eating fish with a mercury concentration above 0.3 ppm may increase blood levels of mercury and cause health issues. 

The mercury amounts in tuna of almost all of the species listed above exceed this concentration, which is why you should eat tuna in moderation and focus on other low-mercury fish and seafood.

If you do want to eat tuna every day or regularly, make sure that you are choosing low mercury tuna varieties such as skipjack or canned light tuna, and avoid yellowfin, albacore, and bigeye tuna.

Canned light tuna also doesn’t really have the omega-3 fatty acids that are anti-inflammatory and beneficial to the body, so to maximize the health benefits of fish in your diet, include salmon, sardines, and other omega-3 fatty acid fish species to get these beneficial fats.

Then, include other low-mercury fish and seafood such as cod, trout, scallops, and oysters in your diet.

Although tuna can be a healthy, high-protein lunch or snack, it is generally not recommended to eat tuna every day. 

Vary your seafood intake as well as your overall proteins, focusing on lean proteins such as chicken, turkey, eggs, plant-based proteins like legumes and soy, lean red meat (occasionally), vegetables, and whole grains.

For some other high-protein lunch alternatives to eating a can of tuna every day for lunch, check out our guide to high-protein lunch ideas here.