Beating a Dead Swordfish

Hiking through and lounging in Cinque Terre was an amazing experience, but unfortunately, several of us were exposed to one of the most toxic elements in the world: mercury. I remember reading the Institute for Agriculture and Trade Policy (IATP) paper about mercury, and for some reason, I was bored enough to actually check out the “Smart Fish Guide” that they recommended to read. As expected, the IATP’s “Smart Fish Guide” overemphasized the danger of mercury in fish and made it seem like the FDA’s recommendation of fish consumption for pregnant women and young children applied to everyone, but it was still interesting to see how swordfish was in the “Do Not Eat” category.

Now back to Cinque Terre. We went to several restaurants, and due to their coastal location, most of us intended to try the seafood. Swordfish was on many of the menus and coincidently, ended up on several of our plates. There have been several discussions on whether or not mercury is going to kill us, but nothing has been said about why large fish have so much mercury despite a lack of HFCS and how mercury goes about wreaking havoc.

Large fish that are high up on the food chain have high levels of mercury due to something called biomagnification. Mercury, and methylmercury (the main source of mercury in fish) are fat soluble, and build up in the organs and muscles of smaller creatures, but organisms are not able to get rid of the mercury. As bigger fish eat smaller fish, they end up taking all of the smaller fish’s mercury, so a large carnivorous fish such as swordfish end up with the most mercury, which then gets passed on to the people who eat the swordfish.

When methylmercury is ingested, it is easily absorbed, and then binds to cysteine present in the body. From there, enzymes in the body confuse the mercury-amino acid complex with methionine, and it is readily transported throughout the body and across the placenta in the case of pregnant women.

http://en.wikipedia.org/wiki/Methylmercury
http://en.wikipedia.org/wiki/Bioaccumulation
http://www.healthobservatory.org/library.cfm?refid=102205