Which Tuna Has the Least Heavy Metals?

October 21, 2025 •

3 min read

According to the U.S. Food and Drug Administration (FDA), canned light tuna, typically made from skipjack, is one of the "Best Choices" for consumption, containing significantly lower average mercury levels than larger species. This makes it the top choice for those concerned about heavy metal accumulation when selecting which tuna has the least heavy metals.

Quick Summary

This article explains which tuna varieties contain the lowest levels of heavy metals, focusing on mercury. It compares popular types like skipjack, albacore, and yellowfin, providing information on how mercury accumulates, why smaller fish are safer, and offering consumption guidelines for adults, children, and pregnant individuals.

Key Points

Canned Light Tuna is Lowest: Canned light tuna, which is typically skipjack, has the lowest mercury levels of all tuna varieties.
Albacore is Moderate: Canned albacore, or white tuna, contains moderate levels of mercury and should be limited to one serving per week.
Bigeye Tuna is Highest: Bigeye tuna, often used for sushi, contains the highest mercury levels and should be avoided by at-risk groups like pregnant women and children.
Smaller Size Means Less Mercury: Mercury levels are generally higher in larger, older tuna species due to bioaccumulation, so smaller fish are a safer choice.
Check Consumption Guidelines: Vulnerable populations, including children and pregnant women, should carefully follow FDA recommendations for tuna consumption.
Geographic Origin Matters: Mercury levels can vary within the same tuna species depending on their catch location, due to differences in environmental contamination.
Consider Other Seafood: For lower mercury and continued omega-3 benefits, explore alternatives like canned salmon, sardines, and shrimp.

Understanding Heavy Metals in Tuna

Heavy metals like mercury can accumulate in fish through a process called bioaccumulation, where the concentration increases with each step up the food chain. Tuna, being a predatory fish, tends to have higher levels of methylmercury compared to smaller fish. The level of heavy metals in tuna is influenced by several factors, including the fish's species, size, age, and geographic location.

Methylmercury is the form of mercury that is most toxic to humans, and high exposure can lead to serious health problems, particularly affecting the central nervous system. Vulnerable populations, such as pregnant women, nursing mothers, and young children, are especially susceptible to the effects of mercury, which can impair neurological development.

The Mercury Difference: Smaller is Safer

As a general rule, the smaller and younger the tuna species, the lower its mercury content. This is because younger, smaller fish have had less time to accumulate the heavy metal from the surrounding water and their diet. This principle is key to understanding why different types of tuna have vastly different mercury levels. This is why canned light tuna is often considered the safest option for regular consumption.

Canned Tuna Varieties and Mercury Levels

Most consumers encounter tuna in canned form, and understanding the differences is crucial for making informed choices. The two primary types of canned tuna available are canned light and canned white, or albacore. Canned light tuna is most often made from skipjack, a smaller, fast-growing species, while canned white tuna is made from albacore, a larger fish.

Skipjack and light tuna are generally the lowest in mercury, making them the "Best Choice" according to the FDA's guidelines. Albacore has significantly higher mercury levels and is considered a "Good Choice" with more limited consumption recommendations. Fresh or frozen tuna steaks, particularly from species like yellowfin and bigeye, typically contain the highest concentrations of mercury and should be consumed sparingly, if at all, especially by sensitive groups.

Comparison of Tuna Species by Mercury Content

To help visualize the difference in mercury levels, here is a comparison table based on data from the FDA and Healthline:


Tuna Species	Mercury Concentration (Mean ppm)	FDA's Consumption Category	Typical Form	Notes
Canned Light (Skipjack)	0.126	Best Choice	Canned	From smaller fish, making it the safest option.
Skipjack (Fresh/Frozen)	0.144	Best Choice	Fresh/Frozen	A low-mercury fresh option, but less common.
Albacore (Canned)	0.350	Good Choice	Canned, Labeled as "White"	Moderate mercury level; limit to one serving per week.
Yellowfin (Fresh/Frozen)	0.354	Good Choice	Fresh/Frozen, Sushi/Sashimi (Ahi)	Higher mercury; check local advisories for sustainability and specific levels.
Bigeye (Fresh/Frozen)	0.689	Choices to Avoid	Fresh/Frozen, Sushi/Sashimi (Ahi)	The highest mercury tuna species; avoid entirely for at-risk groups.

Factors Influencing Mercury Levels Within Species

Even within the same species, mercury levels can vary. A study on yellowfin tuna found significant variation based on the fish's geographic origin, with some sites having much higher mercury loads than others. This highlights that mercury contamination is not uniform across the globe, and factors like regional industrial pollution can play a role.

Safe Consumption and Alternatives

For those who enjoy seafood but want to minimize mercury exposure, especially pregnant women and children, canned light tuna and other low-mercury alternatives are the best choice. Some brands, like Safe Catch, claim to test every fish for mercury, which could offer an extra layer of reassurance for consumers. Other low-mercury fish options include canned salmon, sardines, shrimp, and tilapia.

Conclusion: Making an Informed Choice

When considering which tuna has the least heavy metals, the answer is clear: canned light tuna, primarily made from skipjack, is the best option. Its lower mercury levels, owing to the smaller size of the fish, make it a safer and healthier choice for regular consumption compared to albacore, yellowfin, or bigeye tuna. Consumers should pay attention to labeling, follow FDA guidelines for serving sizes, and consider alternative low-mercury fish to maintain a balanced and healthy diet. By understanding the factors that influence heavy metal accumulation, you can continue to enjoy the nutritional benefits of tuna while minimizing health risks.

For more detailed information on seafood safety and consumption guidelines, refer to the FDA's guide to eating fish.

Frequently Asked Questions

Canned light tuna has the lowest mercury, as it is most often made from smaller, younger skipjack tuna.

Compared to canned light tuna, canned albacore, or white tuna, has significantly higher mercury levels, with the FDA recommending limiting consumption to one serving per week for most adults.

Bigeye tuna, a larger and longer-living species, accumulates more methylmercury over its lifespan through bioaccumulation, making it the type of tuna with the highest mercury content.

Some brands, like Safe Catch, claim to test every individual tuna for mercury to ensure it meets a low limit, though testing by Consumer Reports showed that other light tunas also had comparably low levels.

Pregnant women can have 2 to 3 servings of canned light tuna per week, but should limit albacore tuna to one serving per week, while avoiding high-mercury options like bigeye.

Excellent low-mercury alternatives include canned salmon, sardines, shrimp, scallops, and tilapia, all of which provide valuable omega-3 fatty acids and other nutrients.

The mercury level depends on the species, not whether it's canned or fresh. However, canned light tuna (skipjack) is generally lower in mercury than most fresh tuna steaks from larger species like yellowfin or bigeye.