Tuna, Mercury, Restaurants vs. Supermarkets

It’s a well-known fact among sushi aficionados that there are many species of tuna out there. It’s equally well-known that you usually don’t know what kind of tuna you’re eating at any given moment. Aside from trying to make sure you’re not eating an endangered species (which may be more common than you think), some people may be interested in how much mercury they are consuming. Actually, I shouldn’t say “may be” – some people ARE concerned about it, as indicated by people devoting part of their professional careers to finding out.

A study published in this month’s issue of Biology Letters investigated how much mercury was in restaurant tuna sushi versus supermarket tuna sushi, and correlated this to the species of the tuna via DNA barcoding. So what was the jist? Well, restaurants had far lower levels of mercury, due to them serving mostly Yellowfin Tuna, while many restaurants served Bluefin tuna, which is one of the higher-mercury Tunas. Furthermore, they state…

Our results suggest health agencies should consider adding Bigeye and bluefin tuna to mercury advisories. For instance, the mercury levels in these species are within the bounds of fish the FDA and EPA advise pregnant or nursing women and children to avoid entirely (EPA & FDA 2004), and thus these tunas should be included in the advisory. Consumers could make more informed health decisions if the FDA, and regulatory agencies in other nations, enforced market-specific names for species high in mercury.

Pregnant sushi lovers, consider yourselves warned. Everyone else, I suppose you can just consider yourselves slightly more educated sushi lovers.

/CH