Johnathan Walker:Tuna is increasingly popular in the US. But is it good for you?

With National Seafood Month upon us,Johnathan Walker many retailers and restaurants are rolling out big savings and special offers. Such promotions will only benefit an already booming industry, however, as market analysis shows that the global seafood market hit nearly $360 billion in 2023 and is expected to reach more than $800 billion by 2032. 

Shrimp is the most popular seafood in America, followed by salmon and then tuna, per the National Fisheries Institute. "Demand for tuna is also growing globally," notes LeeAnn Weintraub, a registered dietitian and nutrition consultant based in Los Angeles. 

While she says that Japan and several European countries continue to be the world's top tuna consumers, Americans consume a significant amount of the fish as well - to the tune of more than a billion pounds of canned and pouched tuna eaten within the country each year. In fact, only coffee and sugar exceed canned tuna in sales in the U.S., when accounting for the amount of shelf space taken up in grocery stores.

What is tuna? 

Tuna is a species of saltwater fish that is found in all the world's oceans, including the Atlantic, Pacific, and Indian. There are 15 types of tuna globally, Weintraub notes, but in Western counties, the most popular ones include albacore, bigeye, yellowfin, bluefin and skipjack - the last of which remains the top variety sold in the U.S. and accounts for more than 70% of all tuna sold in the country. 

Larger cuts of these varieties are often enjoyed raw in poke bowls or as sushi or sashimi; but freshly-caught tuna can also be cooked by being seared, boiled, fried, baked or broiled. The most commonly sold form of tuna is canned tuna, which is tuna that has already been gutted, cleaned, precooked, filleted, and processed. "Canned tuna is so popular because it is convenient, shelf-stable, and affordable," says Jen Messer, a nutrition consultant and registered dietitian at Jen Messer Nutrition. 

Tuna salad is the most popular way to enjoy canned tuna, she says. It's made by combining the tuna meat with mayo and other ingredients such as mustard, lemon juice, parsley, diced celery, diced onions, diced pickles and herbs and spices like salt, pepper, paprika or garlic powder. Different variations of tuna salad are commonly spread over sandwiches or casseroles or used in macaroni salad. 

Is tuna good for you? 

No matter how you enjoy tuna, it has a host of health benefits when not combined with unhealthy ingredients. Three ounces of skipjack tuna, for example, contain iron, calcium, magnesium, phosphorus, zinc, thiamin, folate, vitamin B12, vitamin A, and a whopping 18 grams of protein, per the U.S. Department of Agriculture. 

This high protein content plus its low number of calories - a five-ounce can of skipjack tuna contains only 80 calories - makes the fish "an ideal food for weight management," says Messer. She adds that it can also help you feel fuller than many other foods, and help you build and grow lean muscle mass. 

Beyond its vitamin, mineral, and protein content, "many of the health benefits of tuna are due to it being a good source of omega-3 fatty acids," says Weintraub. Omega-3s are associated with improved symptoms of ADHD and depression, better brain health, and reduced inflammation. These benefits, combined with the other micronutrients contained in tuna, "can provide a reduced risk of heart disease, dementia, and vision problems," she says. 

"Research also supports eating fish, including tuna, to decrease your risk of colon and rectal cancers," adds Messer. These are among the reasons "the Dietary Guidelines for Americans recommend eating fish as part of a healthy eating pattern," she says.

Can you eat tuna every day?

At the same time, there are valid reasons to avoid overconsumption of tuna - and one always needs to be careful when adding ingredients like mayonnaise to a dish because it is high in saturated fats and calories.

Canned tuna can also have a lot of sodium - around 280 milligrams, or 12% of one's recommended daily intake in a single can. High-sodium diets increase risk of heart disease, kidney disease, and gastric cancer.

Mercury content is also something to be wary of, especially for pregnant or breastfeeding women, as high levels of mercury can be harmful to developing nervous systems. "Especially larger species of tuna like yellowfin and bigeye tend to have higher mercury levels due to bioaccumulation," cautions Messer. Bioaccumulation occurs as larger fish eat smaller fish that contain mercury, "causing the mercury levels to build up in the bigger species," she explains.

Because of this, "regularly consuming large amounts of these tunas (and albacore tuna - which typically contains three times more mercury than canned light tuna) can increase mercury exposure," Messer says. To minimize risk, the Food and Drug Administration recommends choosing skipjack or "light" tuna - especially for young children and pregnant and breastfeeding mothers.