We all know that fish is high in omega 3 and is considered as the perfect protein, ultra-lean and with loads of heart-healthy fats. What if I told you that it is also lethal in high amounts. It’s true and humans (all of us) are to blame for poisoning ourselves. The reason for their harm is mercury. Yes that red liquid stuff you find in thermometers. Mercury poisoning can be lethal for pregnant women and children. Even Consumer Reports did a whole article on which fish you should limit due to mercury.
How It Started
So the question is how did mercury get into fish? Well lets start with the most common sources of contamination which is coal mining, coal burning power plants, chlorine production plants and gold mining. These processes release mercury and methymercury into the environment. These contaminants reach the rivers and waterways which go into the food chain. Plankton and krill start the food chain and consume mercury. Smaller fish and oysters eat the plankton, while bigger fish eat the smaller fish reaching all the way up to tuna, shark, etc that consume alot of smaller fish. At each step of the way, mercury tends to stay in the fish meat and the more fish you eat, the more mercury you have in your system.
What Fish to Avoid
The bigger the fish in the food chain, the more you should avoid it due to high mercury content. The following fish should be limited in consumption: tilefish, swordfish, shark, king mackerel, grouper, Chilean sea bass, halibut and tuna. Even the canned fish should be limited such as tuna regardless of how it is labeled.
At this point, you are wondering if there are any fish that have no mercury. The answer is no. There are fish have low levels of mercury such as salmon, shrimp, pollock, tilapia, catfish and cod. Seafood (mollusks, crabs, etc) has an added bonus of also containing vitamin D and selenium.
How Does Mercury Poison You?
Mercury is a heavy metal and is well-known to have toxic effects on the nervous system. Mercury interacts with selenium (essential daily vitamin) and causes its enzymes which are vital for brain function and endocrine organs (glands and kidneys) to stop functioning. Some of the symptoms include sensory impairment, lack of coordination, itching, burning sensation, peeling of the skin, swelling and skin discoloration.
The level of poisoning is dependent on a person’s body weight. The heavier you are, the more mercury tolerance you can have. Women who are pregnant and small children are the most vulnerable since it only takes a small amount to affect their sensitive bodies. Fetuses are especially vulnerable and a small amount of mercury can result in deformities.
There is no cure for mercury poisoning, but it can be reversed. You want to limit the exposure as much as possible. Your kidneys will eventually kick it out of your system with the right treatment. Now, a long exposure will do alot of damage to the body especially the central nervous system. Even the best treatments for a long exposure will not reverse what has happened in your body.
Will this affect your sushi consumption?