How Often Can You Eat Tuna Before Mercury Poisoning?

November 22, 2025 •

4 min read

According to the FDA, most adults can safely enjoy 2-3 servings of canned light tuna per week, but how often can you eat tuna before mercury poisoning becomes a concern with higher mercury varieties? The answer depends heavily on the type of tuna and your personal health profile, requiring a mindful approach to your consumption habits.

Quick Summary

This guide provides science-backed recommendations from health authorities like the FDA and EPA on safe tuna consumption levels. It breaks down mercury content differences by tuna type, outlines potential health risks, and explains how to minimize exposure while still enjoying the nutritional benefits of seafood.

Key Points

Choose Low-Mercury Varieties: Canned light tuna (skipjack) has the lowest mercury levels, making it the safest choice for regular consumption.
Limit High-Mercury Tuna: Canned albacore (white) and fresh bigeye or yellowfin tuna contain higher mercury levels and should be eaten less frequently.
Follow FDA Guidelines: Most adults can consume 2-3 servings of canned light tuna weekly, but pregnant women and children need to be more cautious with their intake.
Vulnerable Groups Need Caution: Pregnant women, breastfeeding mothers, and young children are particularly susceptible to mercury's effects and should strictly follow specific guidelines.
Diversify Your Fish Intake: Rotate your fish choices with other low-mercury seafood like salmon and sardines to maximize nutritional benefits and minimize risk.
Consider Selenium’s Role: Tuna contains selenium, a mineral that may offer some protection against mercury's toxicity, but it does not replace the need for mindful consumption.

The Mercury Paradox: Balancing Benefits and Risks

Mercury is a naturally occurring heavy metal that finds its way into oceans, and it can accumulate in fish through a process called bioaccumulation. This happens because smaller fish absorb mercury, and larger predatory fish, like tuna, consume them, concentrating mercury in their tissues over time. While this poses a health risk, especially for vulnerable populations, tuna is also a powerhouse of nutrition. It provides high-quality protein, essential omega-3 fatty acids vital for brain and heart health, and valuable vitamins like D and B12. The key is navigating this dual nature by understanding the specifics of tuna consumption and making informed choices to reap the health benefits without the risks associated with mercury.

Understanding Mercury Levels by Tuna Type

Not all tuna is created equal when it comes to mercury. The levels differ based on the species, with larger and longer-living fish accumulating more mercury. The FDA and EPA have categorized fish to help consumers make safer choices.

Canned Light Tuna (Skipjack): Generally contains the lowest levels of mercury, making it the safest option for more frequent consumption. It's often designated as a "Best Choice".
Canned Albacore Tuna: Known as "white" tuna, this variety has significantly higher mercury levels than canned light tuna. It is classified as a "Good Choice" and should be consumed less frequently.
Fresh or Frozen Tuna (Yellowfin & Bigeye): These species, often used for sushi and steaks, contain the highest mercury levels. Bigeye tuna, in particular, should be avoided by sensitive groups and consumed very rarely by others.

Recommended Consumption Guidelines

For most healthy adults, balancing tuna with other seafood is the recommended approach to enjoy the benefits without excessive mercury exposure. The FDA provides clear guidelines, especially for sensitive populations.

For the General Adult Population: The FDA recommends consuming 8 to 12 ounces of low-mercury fish, including canned light tuna, per week.
For Pregnant or Breastfeeding Women: It is crucial to limit intake and select lower-mercury options. Up to 12 ounces of canned light tuna or up to 4 ounces of albacore tuna is recommended per week.
For Young Children: Serving sizes should be adjusted based on age, with guidance from a pediatrician. Children should primarily stick to the "Best Choices" list, like canned light tuna, and follow specific portion recommendations.

How to Minimize Your Mercury Exposure

Beyond choosing the right type of tuna, several strategies can help reduce your overall exposure to mercury from seafood:

Diversify Your Diet: Don't rely solely on tuna for your fish intake. Incorporate a variety of low-mercury options like salmon, sardines, and pollock to get a wider range of nutrients.
Check the Source: Look for sustainably sourced tuna, often labeled as "pole-and-line caught," which typically comes from smaller, younger fish with lower mercury levels.
Adjust for Your Weight: The standard guidelines are based on average body weight. Smaller individuals, especially children, should consume smaller portions or less frequent servings.
Balance Your Weekly Intake: If you consume a high-mercury fish one week, cut back on fish for the next week or two to let your body's mercury levels naturally decrease.

Mercury Levels in Different Tuna Varieties (per 3 oz / 85g serving)


Tuna Variety	Mercury Content (mean ppm)	Weekly Serving Guideline (Adult)	Considerations
Canned Light (Skipjack)	0.126	2-3 servings	Lowest mercury, safest for regular use.
Canned Albacore (White)	0.350	1 serving	Higher mercury, limit intake.
Fresh/Frozen Yellowfin	0.354	1 serving	Higher mercury, consume sparingly.
Fresh/Frozen Bigeye	0.689	Avoid or consume very rarely	Highest mercury, not for sensitive groups.

The Importance of Selenium

Interestingly, some research suggests that tuna's naturally occurring selenium may offer a protective effect against mercury toxicity. Selenium binds with mercury, forming a complex that is less harmful to the body. However, this does not negate the need for mindful consumption, as the protective effect is not absolute and varies. It is an additional factor to consider, but not a reason to ignore recommended intake limits.

Conclusion

While the risk of mercury poisoning is a valid concern for tuna, it should not be a reason to eliminate this nutrient-rich fish from your diet entirely. By understanding that mercury levels differ significantly by tuna type, you can make smarter choices. Opting for canned light tuna (skipjack) is a safer bet for more frequent consumption, while limiting or avoiding higher-mercury species like fresh yellowfin and bigeye is prudent, especially for vulnerable individuals. Following recommended serving guidelines from health organizations like the FDA ensures you can enjoy tuna's numerous health benefits—from omega-3 fatty acids to protein—in a way that is safe and sustainable for your health. Being a discerning consumer and diversifying your fish intake are the best strategies for a healthy and balanced diet.

For more detailed information on specific fish species and their mercury content, consult the Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) guidelines: EPA/FDA Fish Consumption Advice.

Frequently Asked Questions

The safest type of tuna to eat is canned light tuna, typically made from skipjack. It contains the lowest mercury levels of all tuna varieties and is designated as a "Best Choice" by the FDA and EPA.

Yes, pregnant women can eat tuna, but they should be selective about the type and quantity. The FDA recommends limiting consumption to 2 to 3 servings (about 8 to 12 ounces) of canned light tuna per week, while reducing albacore intake to only 4 ounces per week.

Symptoms of methylmercury poisoning can include memory loss, nerve damage (tingling sensations), tremors, poor coordination, and impaired speech or hearing. High levels over time can affect the kidneys and brain.

In general, fresh tuna, particularly larger species like bigeye and yellowfin, has higher mercury levels than canned tuna. Canned tuna, especially the light variety, is typically made from smaller fish with less accumulated mercury.

Tuna gets contaminated with methylmercury through bioaccumulation, where it gradually accumulates mercury by consuming smaller fish and shellfish. As a predatory fish higher up the food chain, tuna has a higher concentration of mercury than smaller species.

Yes, tuna offers significant health benefits, including high-quality protein, essential omega-3 fatty acids (EPA and DHA), and vitamins and minerals like selenium, vitamin D, and B12. Omega-3s are particularly beneficial for heart and brain health.

While canned tuna labels don't list specific mercury content, you can refer to guidelines from the FDA, EPA, or organizations like the Environmental Working Group (EWG). Some brands, particularly those sourced from specific regions or fishing methods, also market lower-mercury options.