Americans love their tuna fish, though about 95 percent of the tuna we eat is canned. A member of the mackerel family, tuna is a large saltwater fish that may weigh up to 1,500 pounds, depending on the species.
All species of tuna are good sources of high-quality protein and have very little saturated fat. Rich in beneficial long-chain omega-3 fatty acids, tuna is an excellent reservoir of B vitamins such as thiamin, niacin, and vitamin B6. Tuna is also an exceptional source of the antioxidant mineral selenium.
There are, however, lingering concerns about mercury in tuna. Nearly all fish have traces of mercury, but large fish like tuna have more. Because of this, the Food and Drug Administration (FDA) says that pregnant or nursing women and those who might become pregnant should eat 8 to 12 ounces of low-mercury fish a week, which includes canned light tuna—but no more than 4 ounces of white (albacore) tuna a week. This FDA chart lists the mercury levels in fish and shellfish.
There are many types of tuna. For a full listing of nutrients, check the National Nutrient Database. Here is nutritional information on some of popular types of tuna:
Types of tuna
Both fresh and canned tuna are rich sources of nutrients, but if you buy cans it’s best to buy water-packed tuna, which has less fat and sodium than tuna in oil.
There are only a half dozen or so species of tuna that are of commercial importance. Albacore and bluefin tuna are used to make “white meat” canned tuna whereas yellowfin and skipjack are the “light meat” tunas.
- Albacore tuna: This is the most commercially relevant tuna in its canned form. Because most albacore ends up in a can, it is rare to find it fresh in the market.
- Bluefin tuna: This is the largest of the tunas. Young bluefins have lighter flesh and are not too strongly flavored whereas older bluefins have dark red flesh and a more pronounced flavor.
- Skipjack tuna: This is a lighter-fleshed, milder-flavored tuna similar to yellowfin. It’s often used for sushi or sashimi.
- Yellowfin tuna: This tuna is one of the more common tuna types available as fresh steaks in fish markets. Its flesh is darker than albacore, but still light enough to qualify for the “light meat” designation in cans.
How to choose the best tuna
Fresh tuna is most commonly sold in steaks. Generally, the darker the tuna flesh, the stronger the flavor. Indeed, tuna’s deep red almost “beefy” color is darker than that of other types of fish. Like good beef, fresh tuna should be reddish, not brown, when you buy it.
How to store tuna
It’s best to use fresh tuna within a day of buying it, although it can be kept an extra day or two if it is high quality and was very fresh when purchased. Place it, still in the wrapper from the market, in a glass or enameled pan in the coldest part of the refrigerator. Fill a plastic bag with crushed ice and place it on top of the fish. Check the fish daily and pour off any liquid that may have accumulated in the bottom of the pan.
5 ways to serve tuna
- Make a tuna melt. Toast a slice of whole-grain bread and melt a bit of cheddar cheese on it. Add canned tuna and some avocado and sprouts.
- Grill fresh tuna with a squeeze of lime and touch of sea salt.
- Coat fresh tuna with sesame seeds and sear in a hot pan with a bit of oil. Slice thinly and fan the slices over an Asian noodle salad.
- Sear fresh tuna and serve with an avocado salsa.
- Make a tuna pasta salad with whole-wheat pasta, canned tuna, cherry tomatoes, and fresh arugula.