Tuna fish: it’s an inexpensive protein, a go-to workday lunch, and a silver can that makes your kitty happy. But did you know it’s also a nutritional powerhouse? While tuna doesn’t tend to get much glory in the world of seafood, this humble fish offers many more health benefits than you might expect.
Seafood in general nearly always makes an excellent dietary choice. A pescetarian diet—eating vegetarian plus seafood—has been shown to reduce the risk of heart disease and cancer, help manage type 2 diabetes, and maintain healthy weight. Other dietary patterns that emphasize fish consumption, like the Mediterranean and DASH diets, have similar evidence-based health benefits. And the 2015 Dietary Guidelines for Americans (the USDA’s comprehensive manual on diet) recommend consuming about eight ounces a week of “a variety of seafood” (1). Clearly, fish are friends.
So why tuna, and is it safe?
If most all fish is good for you, you may wonder what distinguishes tuna from other types of seafood. Tuna is a saltwater fish from the mackerel family. Fifteen different species swim the seas, from the small (and rather comically named) “bullet” tuna to the 15-foot Atlantic bluefin. Because some species of tuna are close to extinction due to overfishing, certain high-end varieties command outrageous market prices. In 2013, an extremely rare bluefin sold in Japan for 1.8 million dollars (2).
For those of us who aren’t willing to shell out millions on bluefin—or can’t always splurge on pricier seafoods like scallops or swordfish—tuna steaks and canned tuna make a smarter choice for their lower price point and similar nutrient profile to other healthy fish. And whereas fresh fish may require a visual or scent inspection to ensure its safety, you can rest assured that canned tuna is safe for consumption before its use-by date. Prior to canning, tuna is cooked for a required 45 minutes to three hours, then heated after sealing for two to four hours (3).
Why it makes a healthy choice
In addition to its affordability, safety, and lengthy shelf life in cans, tuna boasts valuable advantages for health. Here’s a look at why getting more tuna in your diet can be surprisingly beneficial.
The phrase “fatty fish” may sound unappealing—not to mention unhealthy—but fish that are considered “fatty” are some of the best for your health, especially your heart. Along with salmon, sardines, herring, and lake trout, albacore tuna falls into the category of “fatty” for its high levels of omega-3 fatty acids. Consumption of these unsaturated fats is strongly correlated with cardiovascular health, probably because of omega-3s’ ability to quell inflammation (4). According to the American Heart Association, “Including seafood high in omega-3 fatty acids as part of a heart-healthy diet can help reduce the risk of heart failure, coronary heart disease, cardiac arrest and the most common type of stroke” (5). Sounds like an excellent motivator for getting your eight ounces a week.
Omega-3s have other powerful health effects beyond protecting your heart. They also appear to play a role in preventing cancer. Research has linked increased fish consumption to a reduced risk of breast, prostate, kidney, and bowel cancer (6, 7, 8, 9). And a 2018 study found that marine-based omega-3s were eight times more effective at inhibiting the growth of tumors than even plant-based fatty acids (10). (But we love you, too, plants.)
Have you heard the buzz in recent years about how our fishy friends can boost our brain power? There’s truth behind the hype. A specific omega-3 called DHA (or docosahexaenoic acid) found in fatty fish (including tuna) has significant effects on brain health. In fact, the brain requires DHA in order to maintain normal, efficient function.
DHA appears to help our gray matter in several ways. A 2016 research review of its effects on mental health called it “a promising therapeutic tool” for numerous conditions, such as anxiety disorders, bipolar disorder, obsessive compulsive disorder, and ADHD (11). Other research has confirmed its use for treating type 2 diabetes, dementia, and vision problems (12, 13, 14). According to the Academy of Nutrition and Dietetics, a consistent intake of DHA-rich foods is what ensures the brain benefits of this omega-3 (15). Thankfully, tuna is a one of the best sources.
We’ve covered tuna’s effects on specific health conditions–now let’s talk nutrients. Protein is a macronutrient your body requires to build muscle, heal wounds, and make necessary enzymes. With no additives or anything artificial, tuna serves as an excellent source of this critical macro, at an average of about seven grams per ounce—the same grams-per-ounce ratio (believe it or not) as beef (16). Three ounces of Starkist chunk light tuna packed in water boast about 16 grams of protein, while three ounces of albacore contains 20 grams. Tuna steaks provide a range from 19 to 25 grams. (For reference, the Daily Value of recommended protein intake is just 50 grams.) Put a dent in your day’s requirements with a tuna salad at lunch or grilled tuna steak at dinner.
Vitamins and Minerals
In addition to protein, tuna offers valuable amounts of several vitamins and minerals, such as selenium. Though you might not think very often about your intake of selenium, it’s an essential mineral-slash-antioxidant that’s helps reproduction, thyroid function, and DNA production. It has even been linked to reduced risk for certain cancers (17). Just four ounces of yellowfin tuna can contain twice your daily selenium requirement. Yellowfin is also a good source of Vitamin D, which many Americans don’t get enough of.
Most commercially available varieties of tuna boast B-vitamins, too. Various types of tuna contain anywhere from 20-40% of your day’s requirement of vitamin B6 in three ounces. Also known as pyridoxine, vitamin B6 helps maintain a healthy nervous and immune system and is important for brain development.
Likewise, tuna offers plenteous amounts of vitamin B12—a critical nutrient for cell metabolism. A single serving can provide anywhere from about 30% to a whopping 150% of your daily value (in bluefin tuna).
Albacore or chunk light?
When purchasing canned tuna, you’ve likely chosen between the two options of albacore and “chunk light.” Besides the thicker texture of albacore and thinner consistency of chunk light, what’s the difference? The two actually come from two separate fish. Albacore is derived, of course, from the albacore species of tuna, and chunk light from the smaller skipjack or yellowfin. Nutritionally, albacore and chunk light varieties have some discrepancies, too. Ounce for ounce, chunk light contains slightly fewer calories than albacore (99 versus 109 in three ounces), a bit more protein, and only one-third of the fat. On the flip side, albacore boasts far more omega-3 fatty acids (808 milligrams versus 239 in chunk light).
So which should you choose? It’s up to you based on your tastes, nutrition goals, recipe choices, and price point.
What about mercury?
We seem to recall an episode of House, M.D. where someone got mercury poisoning from eating too much tuna. This TV scenario reflects the truth that mercury is a common concern about tuna for many consumers. After all, it’s a heavy metal that can harm the nervous, digestive, and immune systems. Should you be worried? According to the FDA, “for most people, the risk from mercury by eating fish and shellfish is not a health concern” (18). The Mayo Clinic concurs, stating that “the benefits of eating fish usually outweigh the possible risks of exposure to contaminants” (19). There are concerns of mercury toxicity when intake comes from many sources in the environment and an individual cannot detox appropriately.
Despite these reassurances, we do know that albacore tuna harbors up to three times the more mercury than canned light. For this reason—and because mercury can affect fetal development—the FDA recommends pregnant and nursing mothers consume only up to 12 ounces per week of canned light tuna or six ounces of albacore per week. Read this article to find more information on seafood quality.
If tuna’s strong taste has kept you away in the past, don’t be afraid to experiment with new recipes. Go beyond the sandwich! You never know how a new type of preparation might open up a new world of enjoyment. With its numerous proven health benefits, tuna is a friendly fish you can feel good about including in your diet.