Understanding Mercury in Tuna: Species Over Brand
When questioning which brand of tuna has the most mercury, it's more productive to focus on the type of tuna species inside the can. The primary factor influencing mercury concentration is the fish's size and lifespan; larger, older fish at the top of the food chain accumulate more mercury over time. This is why albacore, or "white" tuna, consistently shows higher mercury levels than smaller, younger species like skipjack, which is typically used for "chunk light" tuna. For example, Consumer Reports testing found that albacore products had, on average, three times more mercury than light tuna.
Can-to-Can Variation and Brand Differences
Despite the general rule that albacore is higher in mercury, studies show that levels can vary unpredictably from one can to the next, even within the same brand and type. This unpredictable variability makes it difficult to definitively name a single brand with the highest mercury. Consumer Reports tests have highlighted these spikes, noting that a significant percentage of samples had high enough mercury to change consumption recommendations. In some instances, they found significant differences between a brand's albacore and its light tuna products.
The Exception: Brands That Test for Mercury
One brand, Safe Catch, stands out by testing every single tuna they catch for mercury content, marketing themselves as having the lowest mercury of any brand. While Consumer Reports found Safe Catch's mercury levels were relatively low, they also noted that the average levels were comparable to other light or skipjack tunas tested. However, Safe Catch's individual testing offers a level of assurance not provided by other brands.
What About Fresh Tuna and Sushi?
Fresh tuna, often used for sushi (e.g., yellowfin, bigeye), is also subject to the same bioaccumulation principles. Larger, older species like bigeye tuna consistently have some of the highest mercury levels among all tuna types and are not recommended for sensitive populations. In contrast, canned light tuna, made from smaller, younger fish, is generally lower in mercury than fresh or frozen tuna steaks.
A Comparison of Canned Tuna Types by Mercury Level
| Tuna Type | Typical Species | Average Mercury Level | Consumer Advice |
|---|---|---|---|
| Chunk Light | Skipjack, Yellowfin | Low | Best Choice. Most adults can safely consume several servings per week. |
| Albacore ("White") | Albacore | Moderate to High | Good Choice. Recommended limit of one 4-ounce serving per week for adults. Not recommended for children or pregnant women. |
| Yellowfin (Fresh/Frozen) | Yellowfin | Moderate to High | Limit consumption to one serving per week due to higher average mercury than light tuna. |
| Bigeye (Sushi Grade) | Bigeye | High | Worst Choice. Highest mercury levels among all tuna species. Avoid, especially for sensitive groups. |
Making Smarter Tuna Choices
To minimize your exposure to mercury, you can follow a few simple strategies:
- Choose light tuna over albacore: The average mercury content in light tuna is significantly lower. Look for "chunk light" or products explicitly labeled "skipjack."
- Eat less tuna overall: Health authorities recommend adults consume a variety of fish rather than relying on tuna as the primary source of seafood.
- Consider low-mercury alternatives: Other fish like salmon, sardines, and tilapia offer great nutritional benefits with much lower mercury content.
- Check the label: While brand doesn't guarantee a specific mercury level, labels can indicate the species and a brand's testing policy, like Safe Catch.
Conclusion: Which brand of tuna has the most mercury?
Ultimately, determining which brand of tuna has the most mercury is less straightforward than identifying the tuna species with the highest levels. Data from Consumer Reports and other studies consistently show that albacore tuna generally contains higher levels of mercury than light or skipjack tuna, regardless of the brand. However, individual cans can have unpredictable spikes in mercury, making it challenging to choose the single "highest" brand without lab testing each can. For consumers concerned about mercury, the best approach is to favor canned light or skipjack tuna, limit overall consumption, and consider brands like Safe Catch that test each fish for added assurance. The key takeaway is that the type of tuna is more critical than the brand name when managing mercury intake. For official guidance and consumption recommendations, the FDA and EPA offer comprehensive guidelines based on species.
