Skip the can of tuna?

Judging by a recent study of canned tuna you might decide to carry on eating tuna and go for the cans without bisfenol A – BPA. Right? Unfortunately there are other risks to take into account. When it comes to tuna they come big. Tuna grow fat on all the other fish they eat. And so they are receptacles of mercury and arsenic that the small fish already ate.

This study gives you the idea that tuna may be safe to eat. But this is not solely a question of risks from the can and we need more information if we want to get to the bottom of this fishy question. The study would have been better if they had included a control test of wild salmon and one of fish-farmed salmon.

Mercury and aresenic in fish are big problem. It isn't just about the can. How does mercury actually get into fish? Mercury itself is a naturally occurring element that is present throughout the environment and found in plants and animals. Human industrial activity, such as coal-fired electricity generation, smelting and the incineration of waste, increases airborne mercury.
Once airborne it eventually finds its way into lakes, rivers and the ocean where it is gobbled up by unsuspecting fish.

Once this mercury gets into the marine food chain, it “bioaccumulates” in the larger predators. That’s why larger fish like tuna are generally riskier to eat than smaller ones. Those of us who eat a lot of mercury-laden fish can suffer from a range of health problems including reproductive troubles and nervous system disorders according to the Scientific American.

Mercury is often found in fish, but children whose mothers eat more fish during pregnancy appear to have fewer behavioral problems, according to a report in Archives of Pediatrics & Adolescent Medicine. 

"These findings underscore the difficulties pregnant women face when trying to balance the nutritional benefits of fish intake with the potential detriments of low-level mercury exposure," says Susan A. Korrick assistant professor of medicine, Harvard Medical School and Brigham and Women's Hospital, USA. "Women need to know that nutrients in fish are good for the brain of a developing fetus, but women need to be aware that high mercury levels in some fish pose a risk."

It is considered safer to eat a varitey of fresh wild fish known to have low levels of contamination like wild salmon, tilapia, shrimp, light tuna, cod, and catfish. All of these have been shown to have lower levels of mercury according to Environmental Defense Fund (EDF).

So for safety sake – skip canned fish. Only eat small fish.