My 12 year-old son has decided that he loves tuna fish. Although I was happy that he finally found a high protein food that he really likes, I was a little disappointed that it had to be tuna. Most people know that tuna contains mercury, a heavy metal that can accumulate in the body and cause serious health problems. I was especially concerned because mercury is particularly harmful to children. It can damage a child’s nervous system, brain, heart, kidneys and lungs. It is too bad he couldn’t have chosen canned salmon (I tried to sneak it by him but he didn’t like it). Here are the 7 facts that you must know about tuna and mercury…
- Mercury accumulates in large predatory fish. Tuna, king mackerel and swordfish are the most contaminated.
- The larger the tuna species, the more mercury it contains. I would avoid Albacore tuna, which has 3 time the levels of mercury compared to the smaller species, such as Skip Jack. Children up to age six shouldn’t eat albacore more than once a month (3 oz. portions); children ages 6–12, twice a month (4.5 oz. portions); adults not more than three times a month (women, 6 oz. portions; men, 8 oz. portions).
- Light tuna is typically from Skip Jack which is a smaller species and contains less mercury than albacore. However, the large tuna companies sometimes use yellowfin for light tuna which is also high in mercury. One study showed that Starkist tuna contained 10 times the amount of mercury compared to other brands of light tuna.
- Skip Jack tuna has the least amount of mercury. Children up to age six can safely eat it three times per month. Older children and adults can safely eat it once a week. It is best if you know the tuna species that you are eating.
- Some smaller seafood retailers offer sustainably caught, species-specific tuna, and contain significantly less mercury. Brands include Eco Fish, Wild Planet, Island Trollers, and High Seas. I found some Wild Planet Skip Jack tuna (see below) at Whole Foods that I can feel comfortable feeding to my kids in moderation.
- The best choice for canned fish is Alaskan salmon which is usually wild caught and contains the lowest mercury levels of any type of fish.
- For more information about seafood, the Environmental Defense Fund has a seafood selector guide that is a must-read for anyone who enjoys seafood. They also have a pocket sushi selector for sushi lovers. The Monterey Bay Aquarium also has a smartphone app which is a great resource for grocery shopping and eating out.