Toxic Tuna

Got Mercury?
Got Mercury?

Some of you have wondered why a Seattle personal trainer like me writes so much about food and so little about exercise. I do in fact own the X Gyms, so wouldn’t it make more sense for me to talk about exercise more than food? The reason I write so much more on nutrition than exercise is because most people want to lose fat as their top goal, and this is accomplished mainly through eating right. In fact 70% of it is due to proper nutrition and only 30% to exercise!

In this post I want to talk about toxins in fish. The reason this is so important is because toxins are stored in your fat tissues, and that makes it harder for the body to empty them back out. Clean fat cells are liberated quite easily, so fat loss is many times over easier to achieve. Your liver must also be healthy to burn fat off your body, and this can only be accomplished if it isn’t kept busy processing toxins. I just talked with an X Gym member this morning whose only meat source is fish. Many people are in this same boat, and there are very important things to know about toxins that build up in large, old fish – especially mercury.

Mercury levels in the Northern Pacific have already increased a staggering 30% in about 15 years, and are expected to rise another 50% by 2050 if China continues to build more coal-fired power plants to fuel its industrial revolution. Asia is an important source of mercury in the Pacific not only because prevailing winds carry air pollution over the ocean where it rains down, but also because ocean currents carry the pollution throughout the basin.

About 40% of all U.S. exposure to mercury comes from eating contaminated tuna from the Pacific, and roughly 75% of all human exposure to mercury comes from eating fish, according to U.S. officials. Mercury poisoning, even very small amounts, early in life can lead to permanent developmental effects. That’s why the government has warned since 2004 that women who are pregnant, and young children, should not eat many species of fish. That’s why the Environmental Protection Agency has been fighting to retain those strong public cautions against efforts by the fishing industry and the Food and Drug Administration to weaken or confuse them.

A new study shows that methylmercury is produced in mid-depth ocean waters by processes linked to the “ocean rain” caused by pollution settling into the water and being absorbed by algae. This algae, which is produced in sunlit waters near the surface, dies quickly and “rains” downward to greater water depths. At depth, the settling algae are decomposed by bacteria and the interaction of this decomposition process in the presence of mercury results in the formation of methylmercury. Many steps up the food chain later, predators like tuna receive methylmercury from the fish they consume.

You can still eat fish if you are careful. The Environmental Defense Fund’s Seafood Selector is the best one-stop source for information about eating only fish that are low in contaminants and harvested sustainably. The Seafood Selector is among The Daily Green’s 10 Food Visionaries Nominated for a 2009 Heart of Green Award.

The Daily Green has compiled several recipes for uncontaminated, sustainable fish, and tips for greening your diet, including how to decipher labels at the fish counter.