Is Canned Tuna Healthy? Yes — But You’re Probably Draining the Best Part

Yes. And the thing most likely to be wasting the good part of it isn’t the can — it’s what you do at the sink.

The worry behind this question is usually that canning cooks the fish to death and destroys the omega-3s, leaving you with expensive protein in a tin. So we went to the USDA’s reference database and pulled the numbers [1].

What is actually in the tin

Start with the top line. Canned pink salmon carries 1.08 grams of EPA and DHA per 100 grams — the two omega-3s that actually do the work [1]. That is not a degraded, apologetic version of fresh fish. That is a serious dose out of a tin you can keep in a cupboard for years. How many years? USDA’s shelf-stable chart gives low-acid cans two to five, and tuna in a retort pouch — the foil packet rather than the tin — eighteen months [5]. The chart does not name fish among its low-acid examples, so read two to five as the range for that whole group rather than a figure measured on tuna.

So the premise of the question is wrong. Canning does not empty the fish out.

But look at the bottom two rows, because that is where the real story is.

The oil is the leak

Albacore tuna canned in water: 0.86 g of omega-3.

Hold that one loosely, though. It is USDA’s reference figure for the category, and actual tins are nowhere near that uniform. When researchers ran eight commercially available US tuna products through gas chromatography — the lab method that separates the individual fats in a sample and weighs each one — the DHA came out anywhere between 90 and 770 mg a serving, and the share of calories coming from fat ran from 3% to 33% [4]. A category average is the right tool for comparing categories. It is the wrong tool for predicting a tin.

The same fish canned in oil: 0.24 g [1].

Same species. Same can. Roughly 72% less omega-3 — and 45% more calories while it is at it [1].

Now the part we owe you, because we went back and checked where those two numbers came from. USDA flags the oil-packed omega-3 figure as a recipe approximation — its own label is “calculated or imputed”, with zero analysed samples recorded — and logs no derivation method at all for the water-packed figure [1]. Of the four rows in that table, only canned pink salmon rests on analysed samples, seventeen of them.

So read the 72% for what it is: the gap between two entries in a reference database, not a number anyone measured in a tin. The direction is solid. The decimal places are not ours to sell you.

So does the mechanism hold up on its own? Yes — and this is where the page should have gone in the first place, instead of reading a process out of an arithmetic gap.

Omega-3s are fats, and fats dissolve in other fats. A systematic review published in June 2026 gathered twenty studies of canned fish across five databases and measured exactly that exchange: omega-3 fats migrating out of the flesh into the packing medium, and the flesh taking up fats from the oil in return until it “increasingly resembl[es] the filling medium” [3]. Then you open the tin, tip it over the sink, and pour part of the reason you bought it down the drain.

Pack the same fish in water and there is far less for the fat to dissolve into, because oil and water don’t mix. Most of it stays in the fish, and you drain off water that never held much you wanted. The review found brine and tomato sauce both held a better fat profile in the flesh than oil did, and that oils heavy in omega-6 — sunflower, soybean — actively pushed the balance the wrong way [3].

The measured products agree. In that gas-chromatography run on eight US tuna products, the omega-6-to-omega-3 ratio — how much of the other family of fats you get for each unit of the one you came for — was 3:1 to 4:1 in the oil-packed tins and 1:3 to 1:7 in the water-packed ones [4]. It does not shrink. It inverts.

One caveat from the same review, and it is ours to pass on rather than bury: canning and storage lower EPA and DHA whatever the tin is filled with [3]. Water packing loses you less. It does not lose you nothing.

Which makes this one of the rare cases where the option that sounds more premium is the one that fails you. “Packed in olive oil” reads as the good tin. It is the one that empties out — unless you use the oil, in which case you keep what dissolved into it.

The mercury question, which is real

This is the part where the honest answer is not simply “eat more”.

The FDA and EPA publish a joint advisory sorting fish into three lists by mercury [2]. One thing to be straight about before we borrow it, because we were not straight about it before: read its own title and it is not addressed to everybody. It is headed “Advice about Eating Fish — For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1 – 11 Years” [2].

We use it anyway, and deliberately, because it is the strictest mercury yardstick any federal agency publishes — if a tin clears a rule written for the most sensitive readers there are, it clears it for everyone. Just know that is the yardstick you are reading, not a limit anybody set for a general adult.

So where does tuna land? The two kinds are not in the same place:

Canned light tuna (including skipjack) is a Best Choice. Albacore — the white one — is only a Good Choice, as is yellowfin [2].

The guidance attached to those lists is filed by population, and both halves of it sit in the same column. Under the heading “Pregnancy and breastfeeding”: a serving is four ounces, and the instruction is to “Eat 2 to 3 servings a week from the ‘Best Choices’ list (OR 1 serving from the ‘Good Choices’ list)” [2]. Children get their own block — one ounce a serving at age one to three, rising to four ounces at eleven, and two servings a week [2].

And if you are in neither group? The same page hands you to the Dietary Guidelines instead, which ask for “At least 8 ounces of seafood (less for children) per week based on a 2,000 calorie diet” [2]. Note the shape of that: a floor, not a ceiling. This page previously printed the two-to-three-a-week figure as though it were general advice and fenced only the serving size to pregnancy. That was backwards, and it is fixed.

And the list to actually avoid is where the mercury really sits. It has seven entries. In full: king mackerel, marlin, orange roughy, shark, swordfish, Gulf tilefish — and bigeye tuna [2].

So yes, there is a tuna on the avoid list, and which tuna is the whole question. The FDA names the canned products separately and by name: “Tuna, canned light (includes skipjack)” is a Best Choice, and “Tuna, albacore/white tuna, canned and fresh/frozen” is a Good Choice [2]. Bigeye is listed with no canned-or-fresh qualifier at all, where albacore carries one — our read is that this is the fish you meet as an ahi steak or across a sushi counter rather than in a tin, and that read is ours, not the FDA’s.

One honest wrinkle, and the label’s fault rather than yours. The federal standard of identity for canned tuna reserves “white” to albacore alone — but “light” is a colour grade, not a species. The regulation opens it to “any tuna not darker than” a fixed mark on a standard lightness scale, and bigeye is one of the fourteen species the same regulation lets into a can [6]. So a light-tuna label tells you a shade, not what was swimming. That is not a reason to doubt the Best Choice rating — the FDA assigned it to canned light tuna as it is actually sold, mercury measured and all. It is a reason not to read “no tuna on the avoid list” off the side of a tin.

So now put the two datasets together

Here is the awkward bit. The tuna with the most omega-3 — albacore in water, at 0.86 g — is also the tuna with the mercury caveat. The tuna you can eat most often, light tuna, carries only 0.27 g [1][2].

You are being asked to pick between the good stuff and the frequent stuff.

Except you are not, because there is a row that wins on both counts. Canned pink salmon has more omega-3 than any of the tunas, and it is a Best Choice [1][2]. So do sardines and anchovies, both also Best Choices [2].

That conclusion is not ours. It falls straight out of putting a nutrient table next to a federal advisory, which apparently nobody does, because the entire internet is arguing about tuna.

What to actually do

Buy it in water, not oil — or buy it in oil and use the oil in the meal instead of pouring it away. That single choice is worth more than everything else on this page [1].

If you want omega-3, reach past the tuna. Canned pink salmon beats every tuna in the table and sits on the safer list, and sardines are on that list too.

If you eat albacore, treat it as the once-a-week tin rather than the everyday one, and if you eat light tuna the advisory’s figure is two to three servings a week [2]. Both of those are the pregnancy-and-breastfeeding column, so they are the cautious end of what any federal agency has put in writing rather than a rule about you. We would still use them as the yardstick. It is your call, not ours — and if mercury is a live question for you for a medical reason, that decision belongs with your clinician and not with a nutrient table.

And stop paying a premium for the tin that drains away three-quarters of what you were buying.