Atlantic cod is one of the healthiest protein sources you can eat. A 4-ounce serving delivers 20 grams of protein for just 90 calories and half a gram of fat. Beyond the impressive protein-to-calorie ratio, cod is packed with micronutrients that many people don’t get enough of, particularly iodine and vitamin B12. It’s also low in mercury compared to many other popular fish.
Protein and Calorie Profile
What makes cod stand out nutritionally is how much protein it packs into so few calories. At 90 calories per 4-ounce serving with 20 grams of protein, cod is leaner than chicken breast and far leaner than beef. The total fat content sits at just 0.5 grams per serving, with virtually no saturated fat. If you’re trying to increase protein intake without adding significant calories, cod is hard to beat.
That leanness does come with a tradeoff. Cod is a white fish, meaning it contains far less omega-3 fat than oily fish like salmon. A 3-ounce serving of Pacific cod provides roughly 140 milligrams of combined EPA and DHA (the two omega-3s linked to heart and brain health). The same portion of wild Atlantic salmon delivers over 1,500 milligrams. So while cod is excellent for lean protein, it shouldn’t be your only source of fish if you’re eating seafood specifically for omega-3s.
Iodine: Cod’s Standout Nutrient
Wild Atlantic cod contains about 114 micrograms of iodine per 100 grams of raw fish, according to a 2023 USDA analysis. The recommended daily intake for most adults is 150 micrograms, so a single serving of cod gets you most of the way there. That matters because iodine deficiency is more common than people realize, even in developed countries.
Your thyroid gland needs iodine to produce the hormones that regulate your metabolism, energy levels, and body temperature. Without enough iodine, the pituitary gland keeps signaling the thyroid to work harder, which can eventually cause the gland to enlarge (a condition called goiter). Beyond preventing deficiency, adequate iodine supports protein synthesis and enzymatic activity throughout the body. Cod is one of the most reliable dietary sources of iodine, alongside dairy and iodized salt.
Mercury Levels in Cod
Cod has a mean mercury concentration of 0.111 parts per million, based on FDA testing. For context, the FDA considers fish with mercury levels below 0.15 ppm to be among the lowest-mercury options available. Swordfish, by comparison, averages around 0.995 ppm, and bigeye tuna comes in at 0.689 ppm. Cod falls comfortably in the low-mercury range, making it safe to eat two to three times per week for most adults, including pregnant women.
What About Microplastics?
A 2025 study examining Atlantic cod caught in the Barents Sea found microplastics in 45% of fillets tested, averaging 0.25 microplastic particles per gram of fish. The particles were mostly polypropylene fragments. Researchers calculated that an average European diet would result in roughly 8 microplastics ingested per week through cod consumption, or about 400 per year.
Those numbers sound alarming, but they’re relatively low compared to other dietary sources. Bottled water, table salt, and even honey contain microplastics at comparable or higher rates. The health effects of ingesting microplastics at these levels are still not well understood, but the concentrations found in cod fillets are not currently considered a reason to avoid eating the fish.
How You Cook It Matters
Baking or broiling cod preserves its nutritional advantages. Deep frying, on the other hand, significantly increases the calorie count, total fat (including saturated fat), and sodium content. A battered, deep-fried cod fillet can easily triple in calories compared to the same piece baked with a light seasoning. If you’re choosing cod for its lean protein profile, frying defeats the purpose.
Baking at moderate heat, poaching, or steaming are the best methods for retaining cod’s nutrients while keeping calories low. A squeeze of lemon, some herbs, and a light drizzle of olive oil is all you need. The mild flavor of cod also makes it one of the easiest fish to prepare for people who don’t love a strong “fishy” taste.
How Cod Compares to Other Fish
- Cod vs. salmon: Cod wins on calories and leanness. Salmon wins decisively on omega-3 content. Eating both regularly gives you the best of each.
- Cod vs. tilapia: Both are mild, lean white fish. Cod generally offers more iodine and slightly more protein per serving.
- Cod vs. tuna: Canned light tuna is comparable in protein, but many tuna varieties carry higher mercury levels. Cod is the safer choice for frequent consumption.
Who Benefits Most From Eating Cod
Cod is particularly useful if you’re trying to lose weight or build muscle, since it delivers a high volume of protein with minimal caloric cost. It’s also a strong choice for anyone concerned about iodine intake, including people who don’t use iodized salt or eat much dairy. The low mercury content makes it one of the safer fish options for pregnant women and young children, populations that benefit from seafood but need to be selective about which types they eat.
People who rely on cod as their primary fish should consider adding an oily fish like salmon, mackerel, or sardines to their rotation once or twice a week to cover their omega-3 needs. Cod alone won’t provide meaningful amounts of EPA and DHA. But as part of a varied diet that includes other seafood, it’s one of the most nutrient-dense, lowest-risk proteins available.