Can I Eat Two Cans of Tuna in One Day? Unpacking the Mercury Risk

December 19, 2025 •

5 min read

According to the U.S. Food and Drug Administration (FDA), adults should aim for 2–3 servings of fish per week, making the consumption of two cans of tuna in one day a significant deviation from recommended intake. While tuna is a lean, protein-rich food, doing so, especially on a regular basis, could expose you to excessive levels of mercury, a neurotoxin that accumulates in the body over time. This article breaks down the risks, benefits, and safer consumption habits to help you make an informed decision.

Quick Summary

The safety of eating two cans of tuna in one day depends largely on the type of tuna due to varying mercury levels. While an occasional deviation may not be harmful, regular intake can lead to a buildup of mercury, particularly if consuming higher-mercury albacore tuna, and should be moderated based on health authority guidelines.

Key Points

Moderate Your Tuna Intake: Eating two cans of tuna in one day exceeds weekly recommendations, especially if done regularly, and increases your risk of mercury accumulation.
Choose Canned Light Tuna: Opt for canned light tuna (typically skipjack) over albacore, as it contains significantly lower levels of mercury.
Vary Your Protein Sources: To reduce mercury exposure, incorporate other low-mercury fish like salmon and sardines or alternative protein sources like chicken and beans into your diet.
Be Aware of Mercury Buildup: Mercury bioaccumulates over time with consistent, excessive consumption, potentially leading to neurological and other health issues, not immediate poisoning.
Special Precautions for Vulnerable Groups: Pregnant women, breastfeeding mothers, and young children are particularly sensitive to mercury and should strictly follow FDA guidelines for fish consumption.
Read Labels and Consult Guidelines: Check labels for the type of tuna and consult official FDA or EPA guidelines to make informed decisions about safe consumption frequency.
Recognize the Benefits and Risks: While tuna provides excellent protein and omega-3s, these benefits must be balanced against the potential risks of excessive mercury intake.

Tuna and Mercury: The Primary Health Concern

The most significant health risk associated with regular and heavy tuna consumption is mercury poisoning. Tuna, being a large predatory fish, accumulates methylmercury throughout its life from the smaller fish it consumes, a process known as biomagnification. This neurotoxin can be damaging to the nervous system and is especially concerning for vulnerable populations such as pregnant women, young children, and breastfeeding mothers.

How Mercury Levels Vary by Tuna Type

Not all tuna is created equal in terms of mercury content. The species of tuna largely determines how much mercury it contains. Smaller, younger tuna like skipjack, which is typically used for canned 'light' tuna, have significantly lower levels of mercury than larger, longer-lived species such as albacore (white) and bigeye tuna. This is why dietary recommendations vary greatly depending on the specific type you are consuming.

Nutritional Benefits of Tuna

Despite the mercury concerns, tuna remains a nutritionally valuable food source. It is an excellent source of lean protein, which is essential for building and repairing muscle tissue and for satiety. Tuna is also rich in essential omega-3 fatty acids, particularly DHA and EPA, which are vital for heart, brain, and eye health. Other key nutrients include vitamin B12, vitamin D, and selenium. Selenium, in particular, has been noted for its potential role in mitigating the harmful effects of mercury.

Mercury Toxicity and Its Symptoms

Methylmercury, the form found in tuna, is not acutely toxic in the small amounts found in fish. The danger lies in its bioaccumulative nature. Chronic, low-dose exposure from frequent, excessive consumption can lead to mercury buildup over time. Symptoms of mercury poisoning can affect the neurological system and may include:

Memory loss
Anxiety and mood swings
Muscle weakness and tremors
Numbness or tingling in extremities
Impaired coordination
Vision or hearing changes

Comparing Different Tuna Varieties for Consumption

To make safer choices, it's helpful to understand the mercury concentration differences among tuna types. The following table compares common canned tuna types based on FDA data, highlighting why moderation is key.


Tuna Type	Average Mercury (ppm)	FDA Recommendation for Adults	Best Choice for Regular Consumption?
Canned Light (Skipjack)	0.126	2-3 servings (8-12 oz) per week	Yes, due to lower mercury.
Canned White (Albacore)	0.350	1 serving (4 oz) per week	Limited, due to higher mercury.
Fresh/Frozen Yellowfin	0.354	1 serving (4 oz) per week (as 'Good Choice')	Limited, similar to albacore.
Fresh/Frozen Bigeye	0.689	Avoid for vulnerable groups; limited for others	High mercury; best to avoid.

Healthy Alternatives and Responsible Consumption

If you find yourself frequently reaching for tuna, diversifying your protein sources is a smart strategy to limit mercury exposure. Lower-mercury fish and other protein-rich foods offer similar nutritional benefits without the same risks. Good alternatives include:

Salmon: A fatty fish rich in omega-3s.
Sardines: Small, low-mercury fish also high in omega-3s.
Shrimp: One of the lowest-mercury seafood options.
Chicken or Turkey: Lean meat alternatives.
Beans and Legumes: Excellent plant-based protein sources.

Conclusion

While consuming two cans of tuna in a single day is unlikely to cause acute mercury poisoning, doing so regularly and ignoring variety in your diet significantly increases your risk over time. The key takeaway is to practice moderation and choose the right type of tuna. Opt for canned light (skipjack) tuna over albacore for lower mercury content, and alternate your tuna intake with other low-mercury fish or alternative protein sources. By following health guidelines from organizations like the FDA, you can continue to enjoy the nutritional benefits of fish while minimizing the potential risks associated with mercury accumulation. For further information and guidelines, consult the FDA's advisory on mercury in fish for specific recommendations.

Tuna: Frequently Asked Questions

Heading: The Safety of Two Cans

The FDA recommends adults eat 8-12 ounces (2-3 cans) of light tuna per week, not per day, due to cumulative mercury exposure. Eating two cans in one day, while not causing immediate acute poisoning, is not advisable as a regular practice.

Heading: Mercury Differences in Tuna

Canned light tuna, which is typically skipjack, contains significantly less mercury than canned albacore (white) tuna because skipjack are smaller and younger fish. Albacore tuna, being a larger predator, accumulates more mercury over its lifespan.

Heading: Are Symptoms of Mercury Poisoning Immediate?

No, symptoms of mercury poisoning from dietary intake are typically not immediate. Methylmercury accumulates in the body over time from consistent, excessive consumption. Symptoms appear gradually, often manifesting as neurological issues.

Heading: Can Pregnant Women Eat Tuna?

Pregnant women and those who may become pregnant are advised to limit their tuna intake due to the fetus's high sensitivity to mercury. The FDA recommends they consume no more than 2-3 servings per week of low-mercury options like canned light tuna, and only one serving per week of albacore tuna.

Heading: What are Good Alternatives to Tuna?

Excellent low-mercury fish alternatives include salmon, sardines, shrimp, and tilapia. Other protein-rich options include chicken, beans, and lentils, which help to diversify your diet and reduce reliance on any single source.

Heading: Does Canned Tuna Have More Mercury Than Fresh?

Canned tuna generally has less mercury than fresh tuna steak because the canned variety often uses smaller species like skipjack. However, specific mercury levels can vary by brand and catch location.

Heading: How Can I Choose Low-Mercury Tuna?

To minimize mercury intake, choose canned light or skipjack tuna. You should also check the label, as some brands test every fish to ensure lower mercury content, and others may specify the species used.

Heading: What Does Omega-3 Content Have to Do with This?

Tuna is a rich source of omega-3 fatty acids, which are beneficial for health. However, the health benefits of omega-3s do not negate the risks associated with excessive mercury intake from overconsuming tuna.

Heading: How Does Mercury Get into Tuna?

Mercury is a naturally occurring element that is released into the environment through human activities like coal-burning. In aquatic ecosystems, it is converted to methylmercury and absorbed by small fish, which are then consumed by larger fish like tuna, causing the mercury to accumulate up the food chain.

Heading: Is Occasional High Tuna Intake Okay?

Consuming more than the recommended amount of tuna on a rare, one-off occasion is unlikely to be harmful, as mercury levels don't spike significantly after a single heavy meal. The concern is with consistent, long-term overconsumption.

Heading: What are the Overall Dietary Recommendations for Fish?

For most adults, the Dietary Guidelines for Americans recommend consuming 8 to 12 ounces of a variety of fish per week, with a focus on low-mercury options. This ensures you receive nutritional benefits while managing mercury exposure.

Heading: Can Cooking Tuna Reduce Mercury Levels?

No, cooking tuna does not reduce its mercury content. Methylmercury is bound to the protein in the fish's flesh and is not affected by heat.

Heading: Is Low-Sodium Canned Tuna Healthier?

From a mercury perspective, low-sodium canned tuna is not inherently safer than regular canned tuna of the same species. However, it can be a healthier choice for individuals monitoring their sodium intake, especially those with high blood pressure.

Frequently Asked Questions

No, eating two cans of tuna in one day is not recommended on a regular basis, as it can lead to an excessive intake of mercury over time. The FDA suggests limiting canned light tuna consumption to 2–3 servings (8–12 ounces) per week for adults and only one serving (4 ounces) of albacore tuna per week.

Eating too much tuna, especially high-mercury varieties like albacore, can lead to a gradual buildup of methylmercury in your body. This can result in neurological issues such as memory loss, tremors, anxiety, and impaired coordination over time.

Yes, canned light tuna, typically made from smaller skipjack tuna, has significantly lower mercury levels than albacore (white) tuna. For this reason, it is generally considered a safer choice for more frequent consumption.

Pregnant women are advised to limit their intake due to mercury's effect on fetal development. The FDA recommends up to 12 ounces of low-mercury fish (like canned light tuna) per week, or up to 4 ounces of albacore tuna, without consuming other fish that week.

Yes, mercury levels can vary between brands and even individual cans. Some brands, like Safe Catch, advertise lower mercury levels by testing each fish, but variations exist across the market.

To reduce mercury exposure while still getting beneficial omega-3s, consider low-mercury options such as salmon, sardines, shrimp, and tilapia.

Yes, tuna is a highly nutritious food, rich in lean protein, omega-3 fatty acids (DHA and EPA), vitamin B12, vitamin D, and selenium. These nutrients support muscle health, brain function, heart health, and the immune system.

Children can eat tuna, but in smaller, limited portions and with a focus on low-mercury options like canned light tuna. The FDA provides specific portion size recommendations based on age.

Symptoms of chronic mercury exposure include muscle weakness, tremors, anxiety, memory loss, poor coordination, and numbness. If you suspect mercury poisoning, you should consult a doctor.

Yes, the geographical origin of the tuna can influence its mercury levels due to regional industrial emissions or volcanic activity. Some experts recommend sourcing tuna from specific fisheries with better health standards, such as those in the U.S..

While tuna offers a specific combination of nutrients, plant-based foods can provide protein and omega-3s. Flax seeds, walnuts, and soybeans are sources of omega-3s, and beans and lentils are great sources of protein.

Mercury is eliminated from the body very slowly, which is why it bioaccumulates over time from consistent dietary intake. Regular, heavy consumption poses a greater risk than occasional high intake.

The packing medium (water vs. oil) primarily affects the calorie and fat content, not the mercury level. While water-packed tuna is lower in calories, the choice does not mitigate the mercury risk associated with the species of tuna.