How much mercury is in canned tuna and is it safe to eat regularly?

What's actually in it

Tuna is a large predatory fish. Large fish accumulate mercury through the food chain. Every small fish they eat contains a little mercury. By the time tuna reaches your plate, the mercury has concentrated. The form found in fish, methylmercury, crosses the blood-brain barrier and accumulates in the nervous system.

Albacore (white) tuna has more mercury than skipjack (light) tuna. The FDA recommends limiting albacore to once per week for adults, and less for pregnant women and children.

What the research says

A 2026 study in Food Chem analyzed mercury in tuna using speciation methods that distinguish different mercury forms. Researchers confirmed methylmercury as the predominant form in tuna tissue. They also tested whether l-cysteine could reduce the bioaccessible fraction, finding it reduced how much mercury the body could absorb from a tuna meal.

The practical takeaway: light canned tuna has lower mercury. Albacore has more. Frequency matters. Eating tuna daily adds up to meaningful mercury exposure over time, especially for pregnant women and children.

Store your tuna in glass food storage rather than plastic to avoid adding plastic chemical exposure on top of the mercury load.