Skipjack tuna, the species sold as “chunk light” in most cans, is the healthiest tuna for regular eating. It delivers solid protein and omega-3 fatty acids while carrying the lowest mercury levels of any common tuna species, averaging just 0.144 parts per million (ppm). That’s less than half the mercury found in albacore or yellowfin, making it safe enough for two to three servings per week for adults.
But “healthiest” depends on what you’re optimizing for. If omega-3s matter most, albacore is the better pick. If you’re pregnant or feeding young children, mercury is the priority and skipjack wins by a wide margin. Here’s how the major species stack up.
Mercury Levels by Tuna Species
Mercury accumulates in fish over time through a process called bioaccumulation: bigger, older fish absorb more. Since tuna species vary dramatically in size and lifespan, their mercury concentrations range from modest to genuinely concerning. FDA monitoring data breaks it down clearly:
- Skipjack (chunk light canned): 0.144 ppm average mercury
- Albacore (white canned or fresh): 0.350 ppm average mercury
- Yellowfin (ahi): 0.354 ppm average mercury
- Bigeye (often sold as ahi at sushi restaurants): 0.689 ppm average mercury
Bigeye tuna carries nearly five times the mercury of skipjack, and individual bigeye samples have tested as high as 1.816 ppm. Yellowfin’s range is also wide, with some samples reaching 1.478 ppm. Skipjack maxes out at 0.26 ppm, which is still low even at its worst.
The EPA and FDA place skipjack in the “Best Choices” category, meaning adults can safely eat two to three servings per week. Albacore and yellowfin fall into “Good Choices,” limited to one serving per week. Bigeye lands in the “Choices to Avoid” category for pregnant women and young children. For kids, the guidance is simpler: stick to two servings per week from the “Best Choices” list.
Omega-3 Content: Where Albacore Stands Out
Omega-3 fatty acids, specifically EPA and DHA, are the main nutritional reason people eat fish in the first place. These fats support heart health, brain function, and reduce inflammation. Not all tuna delivers them equally.
Albacore contains about 1.3 grams of combined EPA and DHA per 100 grams of fish. That’s a substantial amount, comparable to salmon in some preparations. Bluefin tuna is even higher at 1.6 grams per 100 grams, but bluefin is expensive, overfished, and carries elevated mercury. Generic “light” tuna (mostly skipjack) comes in around 0.5 grams per 100 grams, still meaningful but notably less than albacore.
If you eat tuna primarily for omega-3s and you’re a healthy adult without mercury concerns, albacore once a week actually delivers more EPA and DHA than skipjack two or three times a week. The tradeoff is real, and it’s worth thinking about based on your situation.
Canned in Water vs. Oil
The packing medium changes both the calorie count and the omega-3 content more than most people realize. A 5-ounce can of tuna in water has about 120 calories. The same can packed in oil jumps to around 280 calories, more than doubling the energy density without adding much nutritional benefit.
The omega-3 difference is the surprising part. Water-packed tuna retains more DHA than oil-packed tuna. Per ounce, water-packed tuna contains 56 mg of DHA compared to just 29 mg in oil-packed. The likely explanation is that vegetable oil in the can draws the fish’s natural omega-3s out of the meat and into the packing liquid, which most people drain off. If you’re eating tuna for the healthy fats, water-packed is the better choice by a significant margin.
How Catch Method Affects Mercury
This is a detail most people overlook, but it can make a real difference, especially with albacore. Fish caught by handline or pole-and-line methods tend to be younger and smaller than those caught by industrial longlines. Younger fish have had less time to accumulate mercury.
For albacore specifically, handline-caught fish contain roughly one-third the mercury of longline-caught fish. That’s enough to potentially bring albacore’s mercury profile closer to skipjack’s range. Some brands market this directly on the label, often using phrases like “pole-caught” or “troll-caught.” If you prefer albacore’s higher omega-3 content but worry about mercury, seeking out pole-caught varieties is one of the most practical steps you can take.
Selenium’s Protective Role
Tuna is naturally rich in selenium, a mineral that appears to counteract some of mercury’s harmful effects in the body. Mercury damages health partly by interfering with selenium-dependent enzymes that protect cells from oxidative stress. When a fish contains more selenium than mercury (measured as a molar ratio above 1:1), the selenium may offset some of the risk.
Most tuna species maintain selenium-to-mercury ratios above that protective 1:1 threshold. Bluefin tuna is one exception where the ratio can dip lower, along with certain sharks. This doesn’t mean mercury in tuna is harmless, but it does suggest that the health risk from moderate tuna consumption is less severe than looking at mercury numbers alone might imply. The combination of high protein, omega-3s, and selenium in tuna means the net health effect of eating it in recommended amounts is positive for most people.
Choosing the Healthiest Option for You
For most adults eating tuna regularly, skipjack canned in water is the straightforward best choice. It’s low in mercury, affordable, widely available, and retains more omega-3s than oil-packed versions. Two to three cans a week falls well within safe limits.
If you eat tuna less frequently, say once a week, albacore gives you more omega-3 bang for each serving. Look for pole-caught or troll-caught albacore to minimize mercury exposure. Fresh yellowfin (ahi) is fine as an occasional meal but isn’t ideal for weekly consumption due to its variable mercury levels.
Bigeye tuna, commonly served as sushi-grade ahi, is best treated as a rare indulgence rather than a staple. Its average mercury concentration is nearly five times that of skipjack, and individual fish can test far higher. Pregnant women, nursing mothers, and young children should avoid it entirely.
On the packaging side, over 95% of canned foods in the U.S. now use BPA-free linings, so the old concern about can chemicals has largely been addressed across major brands. Between species selection, catch method, and packing medium, species is by far the biggest lever you can pull for a healthier choice.