Can you eat too much tinned tuna?

For Australians, canned tuna is a convenient, protein-rich lunch option, but concerns about “how much is too much” usually center on mercury. Mercury can harm health in high amounts, especially during pregnancy and early childhood, and levels vary by fish species. In Australia, most canned tuna comes from smaller species such as skipjack and yellowfin, generally leading to lower mercury than larger predatory fish like shark or swordfish. Food Standards Australia New Zealand uses an international guideline: a provisional tolerable weekly intake (PTWI) of 3.3 micrograms per kilogram per week for most people, and about half for pregnant women. A 2025 Spanish study measured an average mercury concentration of 0.138 mg/kg across 60 cans, implying roughly 13 micrograms in a 95g can.