How Often Is It Safe to Eat Tuna? What Experts Recommend

QUICK ANSWER  For adults, canned light tuna is generally the lower-mercury choice and can fit into a varied seafood routine a few times a week. Albacore or white tuna should be eaten less often, while bigeye tuna is a high-mercury choice that pregnant people and young children should avoid.

Tuna provides protein, vitamin B12, selenium and other nutrients, making it a popular choice for sandwiches, salads and quick meals. The main reason experts advise moderation is methylmercury, a contaminant that can build up in larger, longer-living fish and affect the nervous system at high exposure levels.

The type of tuna matters

Canned light tuna — Usually made from skipjack, it is listed by the US Food and Drug Administration and Environmental Protection Agency as a lower-mercury ‘Best Choice’. For people who are pregnant or breastfeeding, the agencies advise two to three 4-ounce servings a week from the Best Choices list, while varying the seafood eaten.

Albacore or white tuna — This typically contains about three times as much mercury as canned light tuna. The FDA/EPA chart places it in the ‘Good Choice’ category for pregnancy and childhood, meaning one serving in a week and no other fish that week.

Yellowfin tuna — Yellowfin is also classed as a ‘Good Choice’ under the FDA/EPA advice for sensitive groups, so it should be limited to one serving in a week when following that guidance.

Bigeye tuna — Often sold as ahi tuna, bigeye is on the FDA/EPA ‘Choices to Avoid’ list for people who are pregnant or breastfeeding and for young children because of its higher mercury level.

So, how many times a week is safe?

There is no single limit that applies to every adult in every country. Public-health advice is built around species, serving size and individual risk. A practical interpretation of current expert guidance is:

Why official limits can look different

Recommendations differ because agencies use different serving sizes, categories and population groups. For example, the UK National Health Service tells pregnant people not to exceed four medium cans or two tuna steaks a week. That wording should not be mixed directly with the FDA/EPA categories, which distinguish individual tuna species and mercury levels. Local public-health guidance should take priority.

How to lower mercury exposure without giving up fish

•    Check the label: ‘light’ and ‘white/albacore’ are not the same.
•    Rotate tuna with lower-mercury options such as salmon, sardines, shrimp, pollock or trout.
•    Count portions, not just days; a very large tuna meal may equal more than one serving.
•    Follow local advisories for tuna or other fish caught recreationally.
•    If you eat tuna daily, switch to a more varied pattern rather than relying on one species.

Sources
US Food and Drug Administration. Advice about Eating Fish. https://www.fda.gov/food/consumers/advice-about-eating-fish
US Food and Drug Administration. Questions & Answers from the FDA/EPA Advice about Eating Fish. https://www.fda.gov/food/consumers/questions-answers-fdaepa-advice-about-eating-fish-those-who-might-become-or-are-pregnant-or
US Environmental Protection Agency. EPA-FDA Advice about Eating Fish and Shellfish. https://www.epa.gov/choose-fish-and-shellfish-wisely/epa-fda-advice-about-eating-fish-and-shellfish
NHS. Fish and shellfish. https://www.nhs.uk/live-well/eat-well/food-types/fish-and-shellfish-nutrition/
Editorial note: This original explainer is for general information and does not replace personalised medical advice.