Tuna is a moderate source of iron, providing about 1.4 mg per 3-ounce serving of canned tuna, which covers roughly 8% of the daily value. It won’t compete with red meat, but it has a meaningful advantage over most other fish: the iron it contains is heme iron, the type your body absorbs most efficiently.
How Much Iron Is in Tuna
The iron content varies depending on the type of tuna and how it’s prepared. Fresh skipjack tuna, cooked with dry heat, delivers about 1.36 mg of iron per 3-ounce serving. Canned albacore (white tuna) in water comes in lower, around 0.4 to 1 mg per serving depending on the product. Canned light tuna, typically made from skipjack, tends to land near that 1.4 mg mark.
To put those numbers in context, adult men and women over 51 need 8 mg of iron per day. Women between 19 and 50 need 18 mg daily, and during pregnancy that jumps to 27 mg. A single serving of tuna covers somewhere between 5% and 17% of the daily requirement depending on who’s eating it. It’s a contributor, not a powerhouse.
Tuna vs. Other Proteins
Beef is the clear winner for iron among common proteins. A 3-ounce serving of beef shank provides 3.28 mg, and even a lean ground beef patty delivers 2.3 mg. That’s roughly double what you’d get from the same amount of tuna. Dark chicken meat falls in between at about 2 mg per cup, while lighter cuts like rotisserie chicken back meat drop to 0.7 mg.
Among fish, tuna sits near the top. Salmon, one of the most popular alternatives, provides only 0.6 to 0.65 mg per serving. Cod and haddock are even lower, at under 0.2 mg. Mahi-mahi comes close to tuna at 1.23 mg, and herring edges it out at 1.71 mg per cup. So if you’re choosing fish specifically for iron, tuna is one of your better options.
Why Tuna’s Iron Absorbs Well
Iron from animal sources, including fish, is heme iron. Your body absorbs heme iron significantly more efficiently than the non-heme iron found in plants like spinach, lentils, and fortified cereals. The NIH notes that people following vegetarian diets need 1.8 times more iron than meat eaters precisely because plant iron is harder to absorb.
This means the 1.4 mg of iron in a serving of tuna delivers more usable iron to your bloodstream than the same amount from beans or leafy greens. Pairing tuna with foods rich in vitamin C, like a squeeze of lemon, tomatoes, or bell peppers, can further boost absorption. Your body also absorbs non-heme iron better when it’s eaten alongside heme iron sources, so a tuna salad with spinach actually helps you get more iron from the spinach too.
Mercury and How Often to Eat Tuna
The main trade-off with tuna is mercury. The EPA and FDA recommend eating 2 to 3 servings of fish per week from lower-mercury options, or 1 serving per week from moderate-mercury choices. Canned light tuna (skipjack) falls in the lower-mercury “Best Choices” category, while albacore and yellowfin are in the “Good Choices” tier, meaning you should limit those to one serving per week.
Research on mercury bioaccessibility offers some reassurance for canned tuna specifically. A study examining different preparation methods found that mercury bioaccessibility in canned tuna was less than 20%, meaning your body actually absorbs a relatively small fraction of the mercury present. The same study found that selenium in tuna, which helps counteract mercury’s effects, was present at molar ratios 10 to 74 times higher than methylmercury in the bioaccessible fraction. For canned tuna, a weekly serving was classified as very low risk. Raw or cooked fresh tuna carries higher mercury exposure, and pregnant or nursing women may want to limit those to no more than once a month.
Getting More Iron From Your Diet
If you’re relying on tuna as part of your iron strategy, consistency matters more than any single meal. Two to three servings of canned light tuna per week adds roughly 3 to 4 mg of well-absorbed heme iron to your weekly intake. Pair it with vitamin C-rich foods at the same meal, and you’ll maximize what your body takes in.
For people who need higher iron intake, like women of reproductive age or those with diagnosed deficiency, tuna works best as one piece of a broader approach. Combining it with other heme sources like beef, dark poultry meat, or shellfish across the week, alongside vitamin C-rich vegetables, creates a more reliable iron supply than depending on any single food.