Tuna is a good food for breastfeeding, provided you choose the right type and stick to safe amounts. It delivers omega-3 fatty acids that support your baby’s brain and eye development, along with high-quality protein and selenium. The catch is mercury: different tuna species contain dramatically different levels, so the type you buy matters more than whether you eat tuna at all.
Why Tuna Benefits Breastfeeding Mothers
The main reason tuna earns a spot on your plate while breastfeeding is its omega-3 content. A 3-ounce serving of canned light tuna (typically skipjack) provides 200 to 500 milligrams of EPA and DHA, the two omega-3 fats your baby’s developing brain needs most. Albacore tuna delivers even more, at 500 to 1,000 milligrams per serving. These fats pass directly into breast milk, giving your infant a steady supply during a period of rapid neurological growth.
Research from Harvard Medical School found that maternal fish consumption was linked to better infant development at both 6 and 18 months. At 6 months, infants hit milestones like holding up their head, sitting unsupported, and responding to sounds. By 18 months, children of fish-eating mothers were more likely to walk unassisted, climb stairs, drink from a cup, and begin combining words. The benefit held regardless of how long mothers breastfed.
Beyond omega-3s, tuna is rich in selenium, a mineral that plays a protective role against mercury toxicity. All four common tuna species contain far more selenium than mercury on a molar basis. Skipjack tuna has the highest ratio, with roughly 12 times more selenium than mercury. Even bigeye tuna, the highest-mercury species commonly sold, still contains a meaningful surplus of selenium. This matters because selenium binds to mercury in your body, reducing its ability to cause harm.
Mercury Levels Vary Widely by Tuna Type
Not all tuna is created equal when it comes to mercury. The FDA’s testing data shows a nearly fivefold difference between the lowest and highest mercury tuna species:
- Skipjack (canned light tuna): 0.144 ppm, classified as low mercury
- Albacore (canned white tuna): 0.350 ppm, classified as medium mercury
- Yellowfin (often sold as steaks or sushi): medium mercury range, similar to albacore
- Bigeye (used in sashimi and high-end sushi): 0.689 ppm, classified as high mercury
Canned light tuna is the safest everyday choice. It’s almost always skipjack, which is a smaller, faster-growing fish that accumulates less mercury over its shorter lifespan. Canned albacore (labeled “white tuna”) contains roughly 2.5 times more mercury, so it warrants more caution. Bigeye tuna, the kind you’ll find at sushi restaurants labeled as “ahi,” should be avoided or eaten very rarely while breastfeeding.
How Mercury Reaches Your Baby
When you eat fish containing mercury, your body absorbs methylmercury into your bloodstream. About 10% of the methylmercury in your blood is available to cross into breast milk. That may sound small, but modeling research estimates that breast milk accounts for roughly 80% of a nursing infant’s total mercury exposure in the early months of life. Around 15% of a breastfeeding mother’s total methylmercury burden is excreted through breast milk over the first year, with most of the rest leaving through hair growth.
This doesn’t mean you should avoid fish. It means you should favor low-mercury options and stay within recommended portions. The developmental benefits of omega-3s from fish consistently outweigh the risks when mothers follow serving guidelines.
How Much Tuna You Can Safely Eat
The FDA and EPA recommend that breastfeeding women eat 8 to 12 ounces of seafood per week, choosing from lower-mercury varieties. That’s two to three servings. For canned light tuna, you can comfortably eat two to three servings a week as part of that total. For albacore (white) tuna, limit yourself to one serving per week. Avoid bigeye tuna entirely.
Variety helps. Eating the same fish repeatedly concentrates your exposure to whatever contaminants that species carries. Rotating between tuna, salmon, shrimp, and sardines gives you a broader nutrient profile while keeping mercury intake low.
Lower-Mercury Alternatives With High Omega-3s
If mercury concerns make you uneasy about tuna, several fish deliver equal or higher omega-3 levels with less mercury risk. Salmon (canned or fresh) is the most popular swap, offering generous DHA with very low mercury. Sardines and herring are omega-3 powerhouses that are also inexpensive and widely available canned. Anchovies, trout, and canned mackerel round out the best low-mercury, high-omega-3 options.
Shrimp, pollock, tilapia, cod, and catfish are all low-mercury choices too, though they provide less omega-3 than the fattier fish listed above. They still count toward your weekly seafood goal and contribute protein, iodine, and other nutrients that support milk production and infant growth. If you’re eating two to three servings a week from this broader list, you’re giving your baby meaningful nutritional benefits through your milk.
Practical Tips for Eating Tuna While Breastfeeding
When buying canned tuna, check the label for the species. “Light” tuna is almost always skipjack and is your safest bet. “White” tuna is albacore and should be eaten less frequently. Some brands now list the specific species on the can, which makes choosing easier. Canned tuna packed in water and canned tuna packed in oil have similar mercury levels, so pick whichever you prefer.
At restaurants, ask what type of tuna is being served. Sushi-grade tuna is often bigeye or yellowfin, both higher in mercury than skipjack. A tuna salad sandwich made with canned light tuna is a safer choice than a tuna steak or sushi roll during the months you’re breastfeeding. Fresh or frozen skipjack steaks, when available, are another good option that combines low mercury with the higher omega-3 content of fresh fish.