Can you have too much tuna in a day?

December 31, 2025 •

3 min read

According to the FDA, most adults can consume 8 to 12 ounces of fish per week as part of a healthy diet, but the amount of tuna considered safe depends on the specific species due to varying mercury levels. This heavy metal is the primary reason why daily tuna consumption is cautioned against, especially with certain types of fish.

Quick Summary

Excessive tuna consumption, especially higher-mercury varieties like albacore, can lead to mercury buildup in the body. Safe limits vary by tuna type, and moderation is key to mitigating health risks associated with methylmercury exposure, which can affect the nervous system.

Key Points

Mercury Risk: Tuna accumulates methylmercury, a neurotoxin, which can be harmful in high amounts.
Tuna Type Matters: Canned light tuna (skipjack) has the lowest mercury levels, while canned albacore and fresh tuna (especially bigeye) have the highest.
FDA Guidelines: The FDA recommends weekly serving limits based on tuna type, suggesting 2–3 servings of canned light tuna but only one of albacore per week.
Vulnerable Populations: Pregnant women, breastfeeding women, and young children should be especially cautious with their tuna intake.
Symptoms: Chronic mercury exposure can lead to symptoms like memory loss, anxiety, numbness, and tremors.
Moderation is Key: To enjoy tuna's health benefits safely, practice moderation and diversify your protein sources with other low-mercury seafood.

The Double-Edged Sword of Tuna: Nutrition vs. Mercury

Tuna is a highly popular and convenient protein source, packed with nutrients like omega-3 fatty acids, protein, and B vitamins. However, its position high on the marine food chain means it accumulates significant levels of a neurotoxin called methylmercury. For this reason, the answer to "can you have too much tuna in a day?" is a definitive yes, particularly if you ignore the type of tuna and your overall consumption habits.

Why Mercury is a Concern

Mercury is a naturally occurring element, but industrial pollution has increased the amount found in oceans and waterways. When bacteria convert mercury into methylmercury, it enters the food chain and bioaccumulates, meaning it becomes more concentrated at each successive trophic level. As a large, predatory fish, tuna can have much higher levels of mercury than smaller fish. Regular, high-dose exposure to methylmercury can lead to mercury poisoning, which causes neurological and developmental problems. Vulnerable populations, such as pregnant or breastfeeding women, young children, and those planning a pregnancy, are at higher risk.

FDA Guidelines on Tuna Consumption

The U.S. Food and Drug Administration (FDA) provides clear guidance on safe fish consumption, categorizing fish based on their mercury levels. The recommendations vary significantly depending on the tuna species.

Canned Light Tuna: This is typically made from skipjack tuna, a smaller species with lower mercury levels. The FDA lists it as a "best choice" and recommends adults eat 2–3 servings (8–12 ounces) per week.
Canned Albacore Tuna: Known as "white" tuna, albacore has approximately three times the mercury content of canned light tuna. The FDA advises limiting consumption to one serving (4 ounces) per week.
Fresh or Frozen Tuna (Yellowfin, Bigeye): These varieties, often used for sushi, contain the highest mercury levels. Bigeye tuna, in particular, should be avoided by vulnerable groups and eaten sparingly by others.

Common Symptoms of Mercury Poisoning

While acute, severe mercury poisoning is rare from dietary sources alone, chronic low-level exposure can cause a range of symptoms that build up over time. These include:

Memory loss and concentration issues
Irritability, anxiety, and other mood changes
Numbness or tingling in the extremities
Muscle weakness or poor coordination
Vision changes, such as loss of peripheral vision
Difficulty with speech or hearing
Headaches

If you regularly consume large quantities of tuna and experience any of these symptoms, it's wise to consult a doctor and reduce your intake.

Comparison of Tuna Types and Recommended Intake


Tuna Type	Mercury Level (Relative)	FDA Recommendation for Adults	FDA Recommendation for Pregnant Women & Children	Common Uses
Canned Light (Skipjack)	Low	2–3 servings/week (8–12 oz)	2–3 servings/week (smaller portion)	Sandwiches, salads, casseroles
Canned Albacore (White)	Moderate	1 serving/week (4 oz)	1 serving/week (4 oz)	Higher-end sandwiches, salads
Fresh/Frozen (Yellowfin)	High	Eat sparingly	Avoid	Sushi, seared steaks
Fresh/Frozen (Bigeye)	Highest	Eat sparingly	Avoid entirely	Sushi, sashimi

Balancing Your Seafood Intake

Variety is key to enjoying the benefits of seafood while minimizing mercury exposure. Tuna is a great source of protein and heart-healthy fats, but it shouldn't be your only fish. The USDA Dietary Guidelines recommend eating at least 8 ounces of seafood per week for most adults. To meet this recommendation safely, incorporate a diverse range of lower-mercury fish into your diet, such as salmon, cod, sardines, or anchovies. These alternatives offer similar nutritional benefits with a much lower mercury risk. If you have dietary preferences or medical conditions, discussing a balanced seafood intake with a healthcare professional is advisable.

Conclusion: Practice Moderation and Choose Wisely

While a can of tuna in your lunch is perfectly safe, eating it every day or consuming high-mercury varieties frequently is not recommended. The risk of mercury buildup is real, especially for sensitive populations. The most effective way to enjoy tuna's nutritional benefits while staying safe is to practice moderation and make informed choices about the type you eat. Prioritizing low-mercury options like canned light (skipjack) tuna and diversifying your protein sources is a smart strategy for long-term health. Don't be afraid to mix things up with other delicious, low-mercury seafood options. The key takeaway is balance, not complete avoidance.

For more detailed information on safe seafood consumption, consult the FDA's advice via their official website.

This article is for informational purposes only and is not medical advice. Consult with a healthcare professional before making significant changes to your diet.

Frequently Asked Questions

Eating too much tuna in one day, especially high-mercury varieties like albacore or fresh tuna, significantly increases your exposure to methylmercury. While a single excess doesn't cause immediate poisoning for most, consistent overconsumption can lead to a gradual buildup of mercury in the body, which can cause neurological and developmental problems over time.

Symptoms of mercury poisoning from fish can include memory loss, tingling sensations in the hands and feet, muscle weakness, mood swings, and poor coordination. It is a slow, cumulative process from sustained exposure, rather than a sudden illness.

Canned light tuna, which is most often made from skipjack, has the lowest mercury levels. Because skipjack are smaller and younger when caught, they have less time to accumulate mercury than larger tuna species like albacore.

According to the FDA, eating canned light tuna daily is generally safe for most people, but it's recommended to vary your protein sources. For most adults, 2-3 servings per week are considered safe to meet nutritional needs without excess mercury exposure.

The FDA recommends that pregnant or breastfeeding women can eat 2–3 servings of canned light tuna per week. However, they should limit canned albacore consumption to just one serving per week and avoid high-mercury options like bigeye tuna entirely.

No. Methylmercury is bound to the proteins in the fish tissue, so neither cooking nor draining the tuna will significantly reduce its mercury content.

To reduce mercury intake, choose a variety of seafood, opting for fish lower on the food chain, such as salmon, cod, sardines, and anchovies. Limit your intake of high-mercury fish and stick to recommended serving sizes, especially for albacore and fresh tuna.