How can I enjoy tuna without endangering my health?
BY: Jennifer Viegas
Your reservations about mercury are understandable, since mercury can cause damage to the brain, kidneys and a developing fetus. Unfortunately, industrial pollution releases this toxic metal into the air; it then settles in our lakes, rivers and oceans, and ends up in the fish we eat.
Tuna merits special concern because it's "a large predatory fish that's high up on the food chain," says Timothy Fitzgerald, a scientist with the Oceans Program at Environmental Defense Fund in New York. The higher a fish is on the food chain, the more mercury it's likely to have. This is because mercury contamination starts with small ocean creatures like krill, which absorb mercury from contaminated water. Small fish then eat the contaminated krill; big fish eat the contaminated small fish, and by the time you get to the top of the food chain, you have high concentrations of mercury. Older (and therefore larger) tuna also tend to have more mercury than younger, smaller ones since they have had more time to accumulate mercury in their bodies.
When it comes to fresh tuna, avoid bluefin, which is highest in mercury, advises Fitzgerald. Instead, look for albacore tuna caught in the U.S. or Canada, or bigeye or yellowfin tuna caught by pole or troll (fishing practices that tend to nab smaller, younger fish).
Canned albacore (also known as "white" tuna) tends to come from larger tuna caught outside the U.S. and Canada, and is higher in mercury than the fresh albacore mentioned above. When buying in cans, a better choice is "light tuna," which usually comes from smaller, younger fish and has one-third less mercury than canned albacore, according to Fitzgerald. The best choice, however, may be to switch from canned tuna to canned salmon. "Salmon has less mercury than all types of tuna and it's high in healthy omega-3 fats," says Fitzgerald. In fact, with a bit of mayo, chopped onion and relish, you probably won't taste a difference!
Jennifer Viegas, contributing writer to Live Right Live Well, has covered health, food and fitness for ABC News, Discovery online, the Australian Broadcasting Corp. and Knight Ridder newspapers. The author of more than 20 books, she is also a James Beard Award nominee.