Canned tuna: lean protein, a sodium question and a mercury rule by type

Per 100 g drained, UK data put tuna canned in brine at 109 calories with 24.9 g of protein, 1.0 g of fat, 69 micrograms of selenium and 293 mg of sodium. The can changes tuna mostly through what it is packed in. Raw tuna has 66 mg of sodium per 3.5 oz (100 g), brine-packed 293 mg and oil-packed 368 mg, and fat rises from 0.7 g raw to 6.4 g in sunflower oil, figures from different samples and possibly different species. In USDA data a small can or a pouch holds 75 g and a standard can 115 g. For mercury, US FDA and EPA advice puts canned light tuna among its Best Choices, fine at 2 to 3 servings of 4 oz a week during pregnancy. Albacore, sold as white tuna, typically carries three times the mercury of canned light tuna, and the advice for it is 1 serving a week and no other fish. One finding is a surprise. In double-blind food challenges in a 1992 study, all 45 children and young adults with food allergies who ate canned tuna passed, including 18 with a confirmed IgE allergy to fish, and their antibodies barely bound to extracts of canned fish. That was one small study, and it does not show that a given person with a fish allergy will tolerate a can.

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• UK composition data list 3.5 oz (100 g) of drained tuna canned in brine at 109 calories with 24.9 g protein, 1.0 g fat, 69 ug selenium, 293 mg sodium and 1.1 ug vitamin D. — CoFID 2021 Tuna, canned in brine, drained (16-416) (n = 1 record) Evidence E source
  Per 100 g: energy 109 calories; protein 24.9 g; fat 1.0 g; n-3 PUFA 0.32 g; selenium 69 ug; sodium 293 mg; vitamin D 1.1 ug; iodine 12 ug; cholesterol 47 mg

What a real portion looks like

• In USDA survey data a small can or pouch of tuna holds 75 g, about 64 calories and 14 g protein, a standard can 115 g and a cup 135 g. — USDA FNDDS Fish, tuna, canned (26155110, fdc_id 2706311) (n = 6 measures) Evidence E source
  Per 100 g: 85 calories, protein 19 g, fat 0.94 g, sodium 219 mg, selenium 67.8 ug, vitamin D 1.2 ug, DHA 0.197 g; small can 75 g, standard can 115 g, large can 255 g, cup 135 g, pouch 75 g

What cooking and storage change

• In UK composition data canning changes tuna mostly through what it is packed in: sodium rises from 66 mg per 3.5 oz (100 g) raw to 293 mg in brine and 368 mg in oil, and fat from 0.7 g to 6.4 g in oil. — CoFID 2021 Tuna, flesh only, raw (16-399); canned in brine, drained (16-416); canned in sunflower oil, drained (16-417) (n = 3 records) Evidence E source
  Per 100 g raw / brine / oil: energy 107 / 109 / 159 calories; fat 0.7 / 1.0 / 6.4 g; sodium 66 / 293 / 368 mg; selenium 93 / 69 / 87 ug; vitamin D 3.2 / 1.1 / 1.1 ug
• In double-blind food challenges, all 45 young people with food allergies, 18 of them allergic to fish, tolerated canned tuna. — 45 children and young adults with food allergies, 18 with IgE-mediated fish hypersensitivity (n = 45) Evidence C source
  0 of 45 positive challenges with canned tuna; minimal IgE binding to canned fish extracts

What it does to your health

• In a randomized trial in 400 Spanish adults eating canned tuna in olive oil daily for 3 months, total and LDL cholesterol fell in every group, and added phytosterols lowered LDL further. — 400 adults, mean age 53, 45% men, daily canned tuna in olive oil alone or enriched with isoflavones, omega-3 or phytosterols, 3 months (n = 400) Evidence B source
  Significant reduction of total cholesterol, LDL-C and TC/HDL ratio in all 4 groups; only phytosterols beat plain tuna (p < 0.05); triglycerides and HDL unchanged

Safety, limits and interactions

• Pooling 23 Iranian studies of 1295 cans, mercury in canned tuna averaged 0.11 ug/g, and all metals except cadmium and selenium were below US EPA, WHO and FAO limits. — 23 articles, 1295 canned tuna samples in Iran, 1983-2017 (n = 1295 samples) Evidence C source
  Mean ug/g wet weight: Fe 13.17, Zn 9.31, Se 2.23, As 0.38, Pb 0.24, Cd 0.14, Hg 0.11; THQ <=1 for adults and children
• Across 693 Iranian canned tuna samples, histamine averaged 77.9 mg/kg, under the FDA limit of 200 mg/kg, and was found in about 9% of samples. — 11 studies, 693 canned tuna samples in Iran (n = 693 samples) Evidence C source
  Mean histamine 77.86 mg/kg (95% CI 47.51 to 108.21); prevalence 9.19% (95% CI 6.88 to 11.5)
• A case report describes a 57-year-old man with allergy history who collapsed with a coronary spasm (Kounis syndrome) after eating canned tuna, with histamine fish poisoning in the differential. — one 57-year-old man with hypertension and allergy history (n = 1) Evidence D source
  Facial rash, palpitations, collapse, ST elevation, no coronary atherosclerosis

Who this works differently for

• US FDA and EPA advice puts canned light tuna among Best Choices, fine at 2 to 3 servings a week in pregnancy, and notes albacore typically has three times more mercury. — people who are or might become pregnant, breastfeeding, and parents of young children (n = -) Evidence E source
  Canned light tuna: 2-3 servings of 4 oz per week; albacore (white): about 3x the mercury of canned light tuna, 1 serving a week and no other fish
• In 405 Spanish 9-year-olds, eating more fish, with swordfish, canned tuna and lean fish most strongly, went with more mercury in hair, and 13% exceeded the WHO weekly-intake equivalent. — 405 children aged 9 in the INMA birth cohort, Valencia, 2013-2014 (n = 405) Evidence C source
  Hair mercury geometric mean 0.89 ug/g (0.81 to 0.98); 13% above WHO PTWI equivalent; canned tuna among most associated categories
• In a Spanish cohort of 657 mothers, more canned tuna in the first trimester went with slightly higher arterial stiffness in their children at 11, while total fish intake showed no link. — 657 mother-child pairs in the INMA cohort, children followed to 11-12 years (n = 657) Evidence C source
  Pulse wave velocity beta = 0.1 (95% CI 0.0 to 0.2), p for trend = 0.047 for higher first-trimester canned tuna

The bottom line

In a randomized trial, 400 Spanish adults with a mean age of 53 ate canned tuna in olive oil every day for 3 months, and total and LDL cholesterol fell in all four groups. Every group ate tuna, so there was no arm without it to compare against, and the abstract does not say by how much the numbers fell. Only the arm with added phytosterols beat plain tuna. Contaminant surveys come mostly from one market. Pooling 23 Iranian studies of 1295 cans, mercury averaged 0.11 micrograms per gram, and every metal except cadmium and selenium sat below US EPA, WHO and FAO limits. Cadmium and selenium did not stay below those limits. These are measurements from Iran alone and may not match cans sold elsewhere. Across 693 Iranian samples, histamine averaged 77.9 mg/kg (95% CI 47.5 to 108.2), under the FDA limit of 200 mg/kg, and it was detected in about 9% of samples. Who should be careful. People who are pregnant, might become pregnant or are breastfeeding, and parents of young children, are the group the FDA and EPA advice above is written for, and the choice between light and albacore matters most for them. The 2 to 3 servings of 4 oz are what the advice gives for pregnancy. We hold no card on the portion it gives for young children, so 4 oz should not be read as a child's serving. In 405 Spanish 9-year-olds, eating more fish went with more mercury in hair, with swordfish, canned tuna and lean fish the most strongly linked, and 13% exceeded the WHO weekly-intake equivalent. How much of that came from tuna alone the abstract does not say. In a Spanish cohort of 657 mothers, more canned tuna in the first trimester went with slightly stiffer arteries in their children at 11 (beta 0.1, 95% CI 0.0 to 0.2, p for trend 0.047), a borderline result among many comparisons. If you have a fish allergy, the challenge study above is one small study from 1992, and it is not evidence that canned tuna is safe for you. One case report describes a 57-year-old man with a history of allergy who collapsed with a coronary spasm after eating canned tuna, with histamine fish poisoning among the possible causes. That is a single case.

Sources

1. cntu-daily-r5-01 · food composition dataset
   Tuna, canned in brine, drained (16-416): Energy 109 kcal | Protein 24.9 g | Fat 1.0 g | n-3 poly 0.32 g | Selenium 69 ug | Sodium 293 mg | Vitamin D 1.1 ug | Iodine 12 ug | Cholesterol 47.0 mg
   CoFID 2021 (Public Health England, OGL v3.0), code 16-416 Tuna, canned in brine, drained · checked 2026-09-29
2. cntu-daily-r5-03 · reference dataset
   Fish, tuna, canned, FNDDS 26155110, fdc_id 2706311: 1 cup 135 g | 1 small can 75 g | 1 standard can 115 g | 1 large can 255 g | 1 pouch 75 g | Quantity not specified 85 g || Energy 85 kcal | Protein 19 g | Total lipid (fat) 0.94 g | Sodium, Na 219 mg | Selenium, Se 67.8 ug | Vitamin D (D2 + D3) 1.2 ug | PUFA 22:6 n-3 (DHA) 0.197 g per 100 g
   USDA FNDDS (FoodData Central survey 2024-10-31), Fish, tuna, canned, food code 26155110, fdc_id 2706311 · checked 2026-09-29
3. cntu-daily-r5-02 · food composition dataset
   Tuna, flesh only, raw (16-399): Energy 107 kcal, Fat 0.7 g, Sodium 66 mg, Selenium 93 ug, Vitamin D 3.2 ug || Tuna, canned in brine, drained (16-416): Energy 109 kcal, Fat 1.0 g, Sodium 293 mg, Selenium 69 ug, Vitamin D 1.1 ug || Tuna, canned in sunflower oil, drained (16-417): Energy 159 kcal, Fat 6.4 g, Sodium 368 mg, Selenium 87 ug, Vitamin D 1.1 ug
   CoFID 2021 (Public Health England, OGL v3.0), codes 16-399, 16-416, 16-417 Tuna · checked 2026-09-29
4. cntu-daily-r5-05 · controlled food challenge
   Forty-five children and young adults with food allergies, including 18 patients with IgE-mediated hypersensitivity to fish, were challenged with canned tuna. All 45 challenges with canned tuna were negative.
   J Allergy Clin Immunol, 1992 · checked 2026-09-29
5. cntu-daily-r5-04 · randomized controlled trial
   In all 4 groups a significant reduction of total cholesterol, low-density lipoprotein (LDL)-cholesterol levels and total cholesterol/high-density lipoprotein (HDL)-cholesterol ratio was observed after 3 months of follow-up; there were no significant changes of triglycerides nor HDL-cholesterol levels.
   Med Clin (Barc), 2007 · checked 2026-09-29
6. cntu-daily-r5-07 · meta-analysis of measurement studies
   The ranking order of metals based on mean concentrations (μg/g wet weight) were Fe (13.17) > Zn (9.31) > Se (2.23) > Al (1.8) > Cr (1.63) > Cu (1.52) > As (0.38) > Ni (0.33) > Pb (0.24) > Cd (0.14) > Hg (0.11) > Sn (0.1). Except for Cd and Se, concentrations of other metals in the canned tuna fish were lower than the limits recommended by the United States Environmental Protection Agency (USEPA), World Health Organization (WHO), Food and Agriculture Organization (FAO) and Iran National Standards Organization (INSO).
   Food Chem Toxicol, 2018 · checked 2026-09-29
7. cntu-daily-r5-08 · meta-analysis of measurement studies
   The mean concentration was calculated as 77.86 mg kg−1 (95% confidence interval [CI], 47.51 to 108.21 mg kg−1), which was lower than the 200 mg kg−1 recommended limit by the U.S. Food and Drug Administration (FDA). The mean prevalence of histamine was 9.19% (95%; CI, 6.88 to 11.5%).
   J Food Prot, 2018 · checked 2026-09-29
8. cntu-daily-r5-11 · case report
   We report the case of 57-year-old man, with hypertension and history of allergy, referred for facial rash and palpitations appeared after consumption of canned tuna fish.
   Acta Clin Belg, 2017 · checked 2026-09-29
9. cntu-daily-r5-06 · agency guidance
   Canned light tuna is in the “Best Choices” category and it is fine to eat 2 to 3 servings per week. ... Albacore tuna, also known as white tuna, typically contains three times more mercury than canned light tuna.
   FDA/EPA, Questions & Answers from the FDA/EPA Advice about Eating Fish, 2022 · checked 2026-09-29
10. cntu-daily-r5-09 · cohort
    Thirteen percent of children had THg above the equivalent to the Provisional Tolerable Weekly Intake proposed by the World Health Organization. ... Children's fish intake at 9 years-old was positively associated with THg, being swordfish, canned tuna and lean fish (i.e. hake, sea bream and sole) the most associated categories.
    Environ Int, 2019 · checked 2026-09-29
11. cntu-daily-r5-10 · cohort
    We found a slightly higher PWV (β = 0.1, 95% CI = 0.0; 0.2, p for trend = 0.047) in children whose mothers had a higher consumption of canned tuna during the 1st trimester of pregnancy.
    Nutrients, 2024 · checked 2026-09-29