Packaged tuna is one of the most nutrient-dense, affordable proteins you can keep in your pantry. A single ounce delivers 6 to 8 grams of protein along with omega-3 fatty acids, vitamin D, and minimal carbohydrates. The real question isn’t whether it’s healthy in isolation, but how the type you choose, how often you eat it, and even the packaging itself shift the equation.
Protein and Omega-3s by the Numbers
Tuna packed in water provides about 6 grams of protein per ounce, while tuna packed in oil bumps that up to 8 grams. A standard 5-ounce can in water gives you roughly 30 grams of protein for just 120 calories, making it one of the leanest protein sources available. The same size can packed in oil more than doubles the calories to 280, mostly from the added fat.
Omega-3 content is where things get interesting. Water-packed tuna actually delivers more DHA per ounce (56 mg versus 29 mg in oil-packed), likely because draining oil pulls some of the tuna’s natural omega-3s out with it. Both versions provide EPA as well, though in smaller amounts. These omega-3 fatty acids support heart health, brain function, and help control inflammation throughout the body. You won’t get as much per serving as you would from salmon, but for shelf-stable convenience, tuna holds its own.
Vitamin D is another plus. Oil-packed tuna contains significantly more of it, about 1.9 micrograms per ounce compared to 0.3 micrograms in water-packed. Oil helps preserve fat-soluble vitamins, so if your main goal is vitamin D intake, oil-packed has a clear edge. If you’re watching calories or total fat, water-packed is the better pick.
Water-Packed vs. Oil-Packed
Choosing between water and oil isn’t just about taste preference. A 5-ounce can in oil contains 280 calories versus 120 in water, a difference that adds up quickly if you eat tuna several times a week. Oil-packed tuna tends to have a richer, more tender texture, while water-packed is lighter and works well in salads or mixed with other ingredients.
If you drain oil-packed tuna thoroughly, you lose some calories but also some of those fat-soluble nutrients. The best approach depends on your priorities: water-packed for a lean, high-protein meal with slightly better omega-3 retention, oil-packed for more vitamin D and a fuller flavor. Both are nutritious choices.
Mercury: Light Tuna vs. White Tuna
Mercury is the main health concern with any tuna product. The difference between varieties is significant. According to FDA monitoring data, canned light tuna (typically skipjack) averages 0.126 parts per million of mercury. Canned white tuna (albacore) nearly triples that at 0.350 ppm. This makes light tuna a meaningfully safer option for frequent consumption.
The FDA places canned light tuna in its “Best Choices” category and recommends adults eat at least 8 ounces of seafood per week as part of a balanced diet. For pregnant or breastfeeding women, the guidance is 8 to 12 ounces weekly from lower-mercury options, with a serving size of 4 ounces. That means two to three servings per week of light tuna fits comfortably within safety limits. Albacore falls into the “Good Choices” tier, where the recommendation drops to one serving per week.
Children need smaller portions scaled to their age: about 1 ounce per serving for toddlers ages 1 to 3, 2 ounces for ages 4 to 7, and 3 to 4 ounces for older kids. Two servings per week from the lower-mercury list is the general guideline for children.
BPA and Packaging Concerns
Most metal cans are lined with an epoxy coating that contains BPA, a chemical that can mimic estrogen in the body. Consumer Reports testing found that StarKist canned light tuna averaged 3 parts per billion of BPA, while the same brand in a foil pouch had no measurable BPA at all. If reducing BPA exposure matters to you, pouched tuna is a straightforward swap.
That said, pouch packaging isn’t a universal fix. Some plastic containers tested for other foods actually had higher BPA levels than their canned counterparts, depending on the product and lid type. For tuna specifically, though, the data favors pouches over cans. Many brands now also offer BPA-free can linings, so checking the label is worth the few extra seconds.
Microplastics in Tuna
Like virtually all seafood, tuna contains microplastics. A systematic review covering 19 studies found that contamination levels vary widely depending on species and where the fish was caught. Tuna from the Bay of Bengal showed the highest concentrations, with bigeye tuna averaging over 42 microplastic particles per individual fish. Samples from the Pacific generally showed much lower levels.
Polyethylene and polypropylene, the same plastics used in grocery bags and food containers, were the most commonly detected types. Most particles ranged from 0.5 to 2.5 millimeters, primarily in fiber and fragment form. The health effects of ingesting these quantities of microplastics are still being studied, but this is not unique to tuna. It reflects broader ocean contamination that affects all marine species. Avoiding seafood entirely to dodge microplastics would mean giving up well-established nutritional benefits for a risk that remains poorly quantified.
Making the Healthiest Choice
For most people, the best packaged tuna strategy is simple: choose canned light (skipjack) over albacore to keep mercury low, opt for water-packed if you want fewer calories and slightly more omega-3s, and consider pouches over cans if BPA concerns you. Two to three servings a week fits well within safety guidelines for adults and provides a meaningful boost in protein, omega-3s, and vitamin D.
Watch the sodium content on labels, as some brands pack in over 300 milligrams per serving. Low-sodium versions are widely available and taste nearly identical once you add your own seasoning. Mixing tuna with olive oil, lemon, and vegetables at home gives you the flavor benefits of oil-packed tuna while keeping control over fat quality and total calories.