The safest canned tuna to eat is chunk light tuna, which is typically made from skipjack, a smaller species that averages just 0.126 parts per million (ppm) of mercury. That’s roughly one-third the mercury found in canned albacore (white) tuna, which averages 0.350 ppm. The species inside the can matters more than the brand name on the outside, though a few other factors are worth knowing about.
Why Species Is the Biggest Safety Factor
Mercury accumulates in fish over time through a process called bioaccumulation: bigger, longer-lived fish eat smaller fish and concentrate mercury in their tissue. Skipjack tuna are relatively small and short-lived, which is why they carry the least mercury of any commonly canned species. Albacore live longer and grow larger, so they accumulate nearly three times as much. Yellowfin averages 0.354 ppm, similar to albacore. Bigeye tuna is the worst at 0.689 ppm, though it rarely ends up in cans.
The FDA places canned light tuna (skipjack) in its “Best Choices” category, meaning you can safely eat two to three servings per week. Canned albacore falls into “Good Choices,” limited to one serving per week. A standard serving for adults is four ounces, about the size of a deck of cards.
Decoding the Label
“White tuna” on a can always means albacore. “Light tuna” is usually skipjack, though it can include tongol or other smaller species. If you’re buying for safety, light tuna is the better pick every time. The terms “solid” and “chunk” have nothing to do with species or mercury. Solid (sometimes labeled “fancy”) means the fish was packed in large, firm pieces cut from a single loin. Chunk means smaller, varied pieces. The distinction is texture and price, not safety.
One label worth looking for is “pole and line caught” or “pole caught.” Only about 8% of tuna is harvested this way, one fish at a time. Pole-caught fish tend to be younger and smaller, which generally means less mercury accumulation. It’s also the most sustainable fishing method, with almost zero bycatch of other marine animals.
Brands That Go Beyond the Minimum
Most canned tuna brands simply comply with the FDA’s action limit for mercury, which is 1.0 ppm. That limit is high enough that a can could technically be legal and still contain a significant amount of mercury. Safe Catch is the only brand that tests every individual fish before canning, rejecting any that exceed a mercury threshold ten times stricter than the FDA limit. Their “Elite Wild Tuna” line is specifically marketed toward pregnant women and families with young children. It’s more expensive than mainstream brands, but if mercury is your primary concern, the per-fish testing is meaningful rather than just marketing.
Other brands like Wild Planet and Tonnino use skipjack and emphasize sustainability practices, but they don’t publicize individual mercury testing at the same scale. Choosing any reputable brand of chunk light skipjack tuna still puts you in a low-mercury range.
Limits for Pregnancy and Children
Mercury crosses the placenta and can damage a developing nervous system, causing behavioral and developmental problems. Pregnant or breastfeeding women should stick to two to three servings per week from the “Best Choices” list (light tuna), with each serving at four ounces. Albacore should be limited to one serving per week at most.
Children need smaller portions scaled to their age: about one ounce per serving for ages one to three, two ounces for ages four to seven, three ounces for ages eight to ten, and four ounces at age eleven and up. Two servings per week from the “Best Choices” list is the guideline. In adults, chronic overexposure to mercury can affect the cardiovascular system and, in severe cases, cause confusion, loss of coordination, and other neurological symptoms. These outcomes are associated with sustained, heavy consumption well beyond normal dietary levels, but they illustrate why the weekly limits exist.
The Omega-3 Trade-off
Albacore does have one advantage over skipjack: more omega-3 fatty acids. A three-ounce serving of albacore delivers 500 to 1,000 milligrams of EPA and DHA, the two omega-3s linked to heart and brain health. Canned light tuna in water provides 200 to 500 milligrams per serving. That’s still a meaningful amount, and the lower mercury makes it a better regular choice. If you want the higher omega-3 content of albacore, eating it once a week and filling the rest of your fish servings with light tuna or other low-mercury seafood like salmon or sardines is a reasonable approach.
Can Liners and Chemical Exposure
Mercury isn’t the only concern. Most canned foods, including tuna, use an interior lining to prevent corrosion. For decades, that lining contained BPA, an industrial chemical that migrates into food and has been linked to hormonal, cardiovascular, and reproductive effects. Many manufacturers have moved away from BPA, but the FDA doesn’t require companies to disclose what’s in their can linings. Some cans labeled “BPA free” use replacement chemicals that haven’t been thoroughly studied. Pouched tuna avoids the can liner issue entirely and is worth considering if chemical migration concerns you.
Microplastics in Canned Tuna
A 2022 study published in Food Chemistry analyzed 32 samples of commercially canned tuna and found microplastics in every single one. Tuna packed in water contained more particles (about 692 per 100 grams) than tuna packed in oil (about 442 per 100 grams). The most common plastics identified were polyethylene, PET, polystyrene, and nylon, with 90% of particles smaller than 50 micrometers. The health effects of ingesting microplastics at these levels are still not well understood, but the finding applies across brands and species. This isn’t something you can shop your way around with current products.
A Practical Buying Guide
- Lowest mercury: Chunk light tuna (skipjack), averaging 0.126 ppm. Safe for two to three servings per week.
- Moderate mercury: Canned albacore (white tuna), averaging 0.350 ppm. Limit to one serving per week.
- Best for families: Brands like Safe Catch Elite that test every fish against a strict mercury limit.
- Look for on the label: “Skipjack,” “light tuna,” “pole and line caught,” and “BPA-free” lining or pouch packaging.
- Avoid for regular eating: Bigeye tuna (0.689 ppm average) and yellowfin (0.354 ppm), though these are more common as fresh steaks than canned products.