Understanding Mercury in Canned Tuna
Methylmercury is a neurotoxin that accumulates in fish from environmental sources and poses health risks, especially to sensitive populations like pregnant women and young children. The concentration of mercury in fish is directly linked to their size, age, and position in the food chain. Larger, older, predatory fish tend to have the highest levels. This is why canned tuna, which can come from a variety of species, has different mercury content across its product range.
The Mercury Spectrum: Different Tuna Species
When navigating the canned tuna aisle, the first and most critical factor is the species of tuna. Brands typically use one of two main types: skipjack (chunk light) or albacore (white).
- Skipjack (Chunk Light): This smaller, faster-growing species has a significantly shorter lifespan than albacore. As a result, it has far less time to accumulate mercury. Canned light tuna, which is most often skipjack, is consistently the lowest mercury option.
- Albacore (White): Albacore is a larger species of tuna that lives longer and therefore has higher mercury concentrations. While it is prized for its lighter color and firmer texture, its mercury levels are generally three times higher than skipjack. Some brands, however, have found ways to offer lower-mercury albacore by catching smaller, younger fish.
The Crucial Role of Fishing Methods
Fishing techniques also play a significant role in mercury levels. Conventional methods can catch larger, older tuna, increasing the mercury risk. More discerning, sustainable methods result in a lower-mercury product.
- Pole-and-Line or Troll-Caught: This method involves catching tuna one-by-one at the ocean's surface. This technique predominantly harvests smaller, younger fish that have had less time to accumulate mercury. Many sustainably-minded brands use this method to ensure lower contamination.
- Long-line or Net Fishing: These large-scale industrial methods can inadvertently catch older, larger, and more contaminated tuna, along with other marine life. Brands that rely solely on these methods without testing have more variable and potentially higher mercury levels.
Brands with the Lowest Mercury Standards
Several brands have made it their mission to provide consumers with the lowest possible mercury levels. This is often achieved through rigorous testing and specific fishing methods. The following are some of the most prominent brands known for low-mercury canned tuna:
Safe Catch: The Mercury-Tested Pioneer
Safe Catch is a brand built entirely around the concept of mercury testing. They invented a technology to test every single tuna for its mercury content before it is canned.
- Safe Catch Elite Wild Tuna: This is their flagship low-mercury product, tested to a limit that is 25 times stricter than the FDA's action limit. It uses wild skipjack tuna.
- Safe Catch Albacore: While albacore naturally has more mercury, Safe Catch tests each one to a much stricter limit than the industry standard, resulting in a lower-mercury albacore option.
Wild Planet: Sustainable and Low-Mercury Options
Wild Planet is another brand dedicated to sustainable fishing and a high-quality product. They focus on pole-and-line caught fish to minimize environmental impact and mercury content.
- Wild Planet Skipjack Wild Tuna: Their skipjack tuna is sustainably wild-caught using pole-and-line methods and is a reliably low-mercury choice.
- Wild Planet Albacore Wild Tuna: Also pole-and-line caught, their albacore is younger and smaller than conventional albacore, resulting in lower mercury levels.
Other Low-Mercury Brands to Consider
- American Tuna: This company prides itself on using 100% pole-and-line caught fish, ensuring younger, smaller, and therefore lower-mercury tuna.
- 365 by Whole Foods Market: The store brand's albacore is certified sustainable and pole-and-line caught, offering another low-mercury option.
Comparison Table: Canned Tuna for Low-Mercury Diets
| Brand | Product | Species | Fishing Method | Mercury Level | Key Features |
|---|---|---|---|---|---|
| Safe Catch | Elite Wild Tuna | Skipjack | Wild-Caught | Lowest of any brand, individually tested | Rigorous testing, officially recognized by the American Pregnancy Association. |
| Wild Planet | Skipjack Wild Tuna | Skipjack | Pole & Line | Low | Sustainably caught, non-GMO, kosher. |
| American Tuna | Albacore Tuna | Albacore | Pole & Line | Lower than conventional albacore | Supports local fisheries, minimally processed. |
| 365 by Whole Foods | Albacore Wild Tuna | Albacore | Pole & Line | Lower than conventional albacore | Sustainable, low sodium, good source of protein. |
| Conventional Brands | Chunk Light Tuna | Skipjack (usually) | Varied (often net) | Variable, but generally low | Wide availability, lower price point. |
| Conventional Brands | Solid White Tuna | Albacore | Varied (often long-line) | High | Firmer texture, higher omega-3s but also more mercury. |
Making the Best Choice for You
To ensure you are selecting the safest canned tuna, follow these steps:
- Check the species: Look for 'skipjack' or 'canned light' tuna on the label. This is the most reliable way to minimize mercury exposure. Limit your intake of albacore, and completely avoid bigeye and yellowfin.
- Read the label carefully: Look for keywords like 'pole-and-line caught' or certifications from organizations like the Monterey Bay Aquarium Seafood Watch program.
- Opt for individually tested brands: For the highest assurance, choose a brand like Safe Catch that tests every single fish. This provides a scientific guarantee of a low-mercury product.
Conclusion
Choosing the best canned tuna without mercury doesn't mean giving up this convenient and protein-rich food. By understanding the differences between species, recognizing the impact of fishing methods, and prioritizing transparent brands like Safe Catch and Wild Planet, consumers can make healthy and responsible decisions. Always check product labels for the species and catch method, especially for sensitive groups like pregnant women and children who should be particularly mindful of their mercury intake. Incorporating variety with other low-mercury seafood like salmon and sardines can also reduce overall exposure. For more information on mercury levels in various types of seafood, consult the Environmental Defense Fund's seafood guide.
