First, the scary part. Tuna is a predator fish, so it accumulates methylmercury from all the smaller fish it eats. Think of it as a high-stakes game of "The Floor is Lava," but the lava is heavy metal.
That sounds terrifying, like something out of a sci-fi B-movie where your hair falls out. But relax; you’d have to eat about 10,000 cans a year to get truly sick from mercury poisoning. The real risk is for pregnant people, nursing mothers, and young children—their developing brains are like tiny sponges for this stuff.
The Official "How Often" Rule (Laid Out Like a Bad Diet Plan)
So, for the rest of us nuclear-powered adults? The FDA and EPA, in their infinite wisdom, say two to three servings a week is the sweet spot. A “serving” is about 4 ounces, which is roughly the size of a checkbook or your fist if you’re feeling aggressive.
But here’s the kicker: not all tuna is created equal. There’s a hierarchy, like a strange, fishy monarchy. At the top sits albacore (“white” tuna), which is a bigger fish with three times the mercury of the commoner below.
That commoner is skipjack (“light” tuna), the MVP of the tuna world. It’s smaller, younger, and packs way less mercury. The rule changes: you can eat skipjack like it’s going out of style, but keep albacore to just one serving a week.
And then there’s bigeye tuna, the boss-level fish often used in sushi. You should probably eat that about as often as you see a unicorn. Once a month, if not less. It’s pure mercury with a side of fish.
