Tuna
Tuna: Nutrition, History and Cooking Guide
Tuna encompasses several large, fast-swimming oceanic fish of the Scombridae family, most importantly the bluefin (Thunnus thynnus), yellowfin (T. albacares), bigeye (T. obesus), skipjack (Katsuwonus pelamis), and albacore (T. alalunga). Tuna has been eaten in the Mediterranean since ancient times — Greek and Roman authors describe elaborate trapping systems and mass harvests of Atlantic bluefin. In Japan, tuna — particularly the fatty belly meat of the bluefin, called toro — has been the most prized sushi ingredient since the Edo period, and premium bluefin commands extraordinary prices at Tokyo's Toyosu market. The development of canned tuna in the early twentieth century, beginning in California in the 1900s, transformed tuna from a luxury into a global everyday protein. Today, tuna is the most commercially significant fish in the world by value, with skipjack the dominant species in canning.
Nutritional Value of Tuna
Tuna provides 144 kcal and 23.3 g of protein per 100 g, with 4.9 g of fat — one of the highest protein-to-calorie ratios of any meat or fish. It is an excellent source of omega-3 fatty acids (particularly DHA), niacin, B12, B6, selenium, and phosphorus. Canned tuna in water retains these nutrients well; canned in oil adds additional calories from the surrounding oil.
Health Benefits of Tuna
Tuna is a lean, high-quality protein with outstanding nutrient density. Its omega-3 DHA content supports brain health and cardiovascular function. Niacin contributes to energy metabolism. The selenium content supports thyroid function and antioxidant defence. However, larger tuna species — particularly bigeye, albacore, and bluefin — can accumulate methylmercury, a concern particularly for pregnant women, nursing mothers, and young children, who are advised to limit consumption of these species. Skipjack and light canned tuna have lower mercury levels and are generally considered safe for regular consumption.
How to Select and Store Tuna
Fresh tuna should be deep red to ruby in colour, firm, and smell of the sea. Avoid brownish or grey flesh. Refrigerate and use within two days; freeze for up to three months. Sashimi-grade tuna has been frozen to parasite-killing temperatures and can be eaten raw. For canned, choose tuna in spring water for lower calorie content or in olive oil for better flavour.
How to Cook Tuna
Fresh tuna steaks are best seared quickly — one to two minutes per side in a very hot pan — leaving the centre rare to medium-rare, which preserves moisture and texture. Well-done tuna becomes very dry. Season simply with salt, pepper, and a drizzle of soy and sesame for Japanese-inspired preparation, or with olive oil and Mediterranean herbs. Canned tuna needs no cooking and works in pasta, salads, sandwiches, and fishcakes.
Micronutrients (per 100g, cooked)
| Nutrient | Amount | % adult reference intake |
|---|---|---|
| Minerals | ||
| Iron | 0.93 mg | 6% |
| Calcium | 11 mg | 2% |
| Magnesium | 41 mg | 14% |
| Potassium | 450 mg | 13% |
| Sodium | 63 mg | 4% |
| Chloride | 130 mg | 5% |
| Phosphorus | 290 mg | 53% |
| Zinc | 0.5 mg | 5% |
| Copper | 0.03 mg | 3% |
| Manganese | 0.01 mg | 1% |
| Iodine | 23 ug | 16% |
| Selenium | 92 ug | 123% |
| Vitamins | ||
| Vitamin A | 78 ug | 11% |
| Vitamin C | Tr (trace) | . |
| Vitamin D | 3.1 ug | 31% |
| Vitamin E | 0.13 mg | 3% |
| Vitamin K | not measured | . |
| Vitamin B1 (thiamin) | 0.12 mg | 12% |
| Vitamin B2 (riboflavin) | 0.07 mg | 5% |
| Vitamin B3 (niacin) | 24.9 mg | 146% |
| Vitamin B5 (pantothenic acid) | 0.21 mg | 3% |
| Vitamin B6 | 0.23 mg | 16% |
| Vitamin B7 (biotin) | 2.9 ug | 1% |
| Vitamin B9 (folate) | 5 ug | 3% |
| Vitamin B12 | 2.2 ug | 147% |
Source: CoFID 2021 (McCance and Widdowson, UK), code 16-400 (matched record: "Tuna, flesh only, baked"). N = present but not quantified; Tr = trace; not measured = no value in the source.
What this food is a source of
High in by content (per 100g): Vitamin B12 (147%), Vitamin B3 (niacin) (146%), Selenium (123%), Phosphorus (53%), Vitamin D (31%).
A source of by content (per 100g): Vitamin B6 (16%), Iodine (16%).
These figures are the amount in the food. How much the body absorbs can vary, see each nutrient's entry for detail.