Canned tuna is one of the most nutrient-dense, affordable proteins you can buy. A 3-ounce serving of yellowfin tuna delivers about 25 grams of protein for only 110 calories, with 89% of its calories coming from protein alone. That ratio beats even skinless chicken breast. But the “is it healthy” question usually comes down to mercury, and the answer depends on which type of tuna you’re eating and how often.
What Makes Canned Tuna So Nutritious
Tuna is rich in omega-3 fatty acids, the type of fat most strongly linked to heart health. The American Heart Association recommends one to two meals of non-fried fish per week for better cardiovascular health, and specifically names albacore tuna as a high-omega-3 option. Omega-3s from seafood decrease the risk of abnormal heart rhythms that can lead to sudden death, lower triglyceride levels, and slow the buildup of fatty deposits in arteries.
Beyond heart health, tuna is a strong source of selenium, B vitamins, and vitamin D. Selenium plays an especially interesting role in tuna: it has an extremely high chemical affinity for mercury, essentially binding to it and reducing mercury’s biological availability in your body. This means the selenium naturally present in tuna partially offsets the mercury risk, though it doesn’t eliminate it entirely.
Water-Packed vs. Oil-Packed Tuna
The packing medium changes both the calorie count and the omega-3 content more than most people realize. A 5-ounce can of tuna in water has about 120 calories, while the same size can packed in oil jumps to 280 calories. That’s more than double.
The omega-3 difference is less intuitive. Per ounce, water-packed tuna actually contains nearly twice the DHA (the most beneficial omega-3) as oil-packed tuna: 56 mg versus 29 mg. The oil in the can doesn’t add omega-3s. Instead, it dilutes tuna’s natural omega-3 concentration and replaces it with whatever oil was used, typically soybean oil. If you’re eating tuna for the protein and omega-3 benefits, water-packed is the better choice.
The Mercury Question: Light vs. White Tuna
Mercury is the main health concern with canned tuna, and the risk varies dramatically between types. The key distinction is between “light” tuna (usually skipjack) and “white” tuna (albacore). Skipjack tuna, the most commonly canned species worldwide, has the lowest mercury concentrations among all major tuna species, falling below the U.S. consumption guideline of 0.22 parts per million. Albacore averages above that threshold, ranging from 0.22 to 0.95 ppm.
That difference translates into very different safety recommendations. According to the Biodiversity Research Institute, skipjack (light) tuna is safe for one to two meals per week. Albacore (white) tuna should be limited to about one meal per month for people concerned about mercury exposure. If you’re eating canned tuna regularly, choosing light tuna over white tuna is the single most effective way to reduce your mercury intake.
For most adults, the risk from moderate tuna consumption is low. The FDA notes that most types of seafood don’t contain mercury levels that would cause health effects in adults, and that adverse effects “usually require a level of methylmercury not generally found in seafood products.” The AHA puts it more bluntly: for adults eating a serving or two of fish per week, the cardiovascular benefits outweigh concerns about contaminants by at least fiftyfold.
Mercury Risk for Pregnant Women and Children
The calculus shifts for pregnant and breastfeeding women and for young children. Mercury crosses the placenta and is particularly harmful during periods of active brain development, where it can affect measures of intelligence, memory, cognition, and motor skills in children. The EPA and FDA recommend that pregnant or breastfeeding women eat 8 to 12 ounces per week of seafood from lower-mercury options, and that children eat two servings per week from the lowest-mercury (“Best Choices”) category. Light (skipjack) tuna fits in that category. Albacore does not.
Signs of Too Much Mercury
Clinical mercury toxicity from normal fish consumption is rare, but it’s worth knowing the symptoms. In adults, excessive mercury exposure can cause depression, memory problems, numbness, muscle weakness, difficulty walking, changes in speech or vision, problems with balance, and a metallic taste in the mouth. These symptoms can develop gradually or appear suddenly. If you’re eating canned tuna daily (especially albacore), cutting back and talking to a healthcare provider about testing is reasonable.
What About BPA in the Can?
For years, the lining inside cans contained BPA, a chemical linked to endocrine disruption. That concern has largely been addressed by the industry. More than 95% of canned foods sold in the U.S. are now made without BPA-containing liners, according to Oregon State University’s Extension Service. The FDA considers the amounts currently used in remaining cans safe for humans, though some manufacturers now label their products “BPA-free” if that matters to you.
How Much Canned Tuna to Eat Per Week
For most adults, two to three servings of light (skipjack) tuna per week fits comfortably within federal guidelines. A serving is about 3.5 ounces, roughly three-quarters of a cup of flaked tuna. If you prefer albacore for its firmer texture and milder flavor, limit it to one serving per week or less. Mixing tuna with other low-mercury fish like salmon, sardines, or herring throughout the week gives you variety in omega-3 sources while keeping mercury exposure low.
For pregnant women, sticking to light tuna and staying within the 8-to-12-ounce weekly seafood range is a practical approach. For young children, two smaller servings of light tuna per week aligns with EPA and FDA guidance. In both cases, the goal is getting the developmental and cardiovascular benefits of omega-3s without unnecessary mercury exposure.