sushirx1.jpgHow safe is your sushi?  Part One:  Mercury!
By Ross A. Christensen
 

Recently it seems that news has flooded the internet about mercury in your tuna.  Should your dining experience change with this news?  Has something happened to the tuna industry that would cause this emergency?  Should we abandon sushi bar for the dim sum bar? What is going on? 

First of all, let’s set one thing straight, and that is what mercury IS.  Being that I live very close to an abandoned mercury mine/Superfund site I’ve looked into the issue extensively, and feel fairly well qualified to answer this one.  Mercury is a naturally occurring metal which runs freely through our ecosystem just like any other natural element, and it has been around just as long as all the other elements in our biosphere.  Mercury in the biosystem is typically consumed by microorganisms that then convert it into the most toxic version, methylmercury.  This is an organic compound that is toxic to living creatures.  No, I didn’t say poisonous, I said toxic, and there is a difference. Toxic denotes that living creatures can handle certain amounts of an element without noticeable results (e.g., carbon dioxide; a small amount doesn’t harm us at all, but large amounts can cause death). Mercury can be compared to carbon dioxide and methylmercury is comparable to carbon monoxide, a much more toxic version of its predecessor. Methylmercury is 100 to 1000 times more toxic than plain mercury.  Interestingly enough, the toxicity of mercury/methymercury is under constant debate and is still not fully agreed upon. Even European countries, although they share a currency, don’t agree on toxic mercury levels.

Mercury is in almost every living thing simply due to the cycle of life.  It falls in the rain, is absorbed into the soil and grass, is then consumed by the cow, and then grilled to perfection and eaten by us.  If cows were carnivorous and ate the neighbor’s cats, then beef would have dangerous amounts of mercury in it.  So make a mental note:  lions and tigers and bears should not be eaten, if only for the chance of high mercury levels. 

Mercury comes from many different sources.  Environmentalists may screech about the evils of mercury being produced from coal burning plants, or gold, steel, battery and cement producers, but they account for only about half of the amount of atmospheric mercury on the planet.  Mother Nature has to take credit for the rest, which comes spewing forth from her volcanoes.

Symptoms of mercury poisoning are heavy sweating; high blood pressure; persistent pain, itching, or burning sensation on the skin; tremors and twitching; headaches; loss of hair, layers of skin, and/or fingernails. Extreme cases can cause memory loss and loss of IQ.  Mercury binds itself to the proteins of tissue and over time accumulates in the system.  Mercury poisoning can be treated by your doctor in a relatively easy process.  However, due to its binding action, it is impossible to remove mercury from your fish. 

Those are the plain, bald facts about mercury.  So why all the concern about the dangers of mercury right now? One of the reasons this news has come forward is that in 2004 the FDA and the EPA joined forces to warn women to limit canned tuna intake if they were pregnant or planned to get pregnant.  So the media, as usual, by not giving the public the whole truth and instead focusing on sensationalism and marketing doom, gave the public the frosting and not the cake.  This “dangerous” tuna in sushi often comes from the very same fish that is going into the sandwich that you put in your child’s lunchbox every day, your common canned tuna.  There have been several studies done on mercury levels and they have shown that mercury levels in fish have actually lowered over the past 100 years.  (I can hear the editor now, “Take that information out of the article, it won’t sell papers! And get me more pictures of Spiderman!”)

Okay, time for a short rant here:  Newspapers love to cause alarm.  Headlines that read, “Everything’s fine, nothing interesting going on” don’t sell papers.  In order to increase a paper’s circulation it seems necessary to threaten the health and safety of America’s children. Whenever you read about dangerous amounts of mercury in sushi, an article will say “Can cause learning disabilities in children!” The choice of words is what the important thing here is.  You’ll notice that you’ve never read “HAS caused or IS CAUSING learning disabilities in these children.”  Spin; it’s all in how a thing is phrased.  This is a tactic that midwives in America could grasp onto: “Hundreds of thousands of children are put at risk of death by driving the mother in labor to the hospital. These babies’ safety could be ensured by giving birth at home and avoiding risks of traffic collisions, toxic highway fumes, and UV exposure!”  It’s all hype, don’t buy into it.  Since almost nobody agrees what a dangerous amount of exposure/consumption of mercury is, crying “harmful amounts of mercury!” is just Chicken Little, “the sky is falling” type of reporting.

The sushi pieces that were actually reported to be high in mercury levels were tested to find they had one part per million in the samples.  According to the FDA’s OWN RULES, pregnant women should limit eating fish containing one part mercury per million to SEVEN OUNCES PER WEEK!  This is the very tuna that the newspaper is exclaiming is hazardous, but it obviously isn’t so hazardous if the FDA thinks that pregnant women can eat that very type of sushi several times per week!  WOW! If pregnant women can have seven ounces a week, I should have free reign!

My daughter has eaten sushi, raw oysters, and all kinds of seafood since she was five years old, and she’s an A student with no signs of developmental disabilities or social disorders.  To date, most studies have shown that the benefits of seafood consumption far outweigh the risks.  So while studies have shown the documented benefits of seafood, fear mongers preach ethereal phantasms of dangers, risks, and possibilities. Another problem that should be mentioned regarding these reports is that the FDA and the EPA don’t even use the same criteria of what constitutes a safe amount of mercury a person should be able to consume.  If they don’t agree, whose guidelines are the public supposed to follow?

Mercury poisoning can occur in a person in two ways, through ingesting a ridiculously large amount in one shot, or through a lifetime of accumulation.  To give you a comparison, you may inhale a pound of carbon monoxide throughout your lifetime and your body can handle that without problem.  However, if you were to inhale that entire amount in one hour, your body couldn’t handle that and you wouldn’t survive.  (Of course, small amounts of carbon monoxide are released from your system by respiration, whereas mercury is not released from your system without treatment.)  It takes a long time to accumulate enough mercury to become a problem, and even then it won’t kill you. And even then, there is not enough evidence from concurring studies to show what is “dangerous” for all people.  One person’s dangerous level may not be dangerous for the next person. 

The problem with “the dangers of mercury” is that what the FDA and EPA use as “hazardous amounts” aren’t actual dangerous numbers.  The level considered hazardous was chosen because one part per million is ten times less than what it allegedly takes for a person to become symptomatic of mercury poisoning while ingesting it in one sitting. 

It’s like one day they polled the staff and said, “What level of mercury should we tell the public is dangerous?”  Then someone raised their hand and said “How about one part per million?” and everyone agreed.  There is no evidence that one part per million is any better or worse than one half of a part per million or three parts per million.  And it’s just not accurate to say, “If you eat ten parts per million of mercury you should immediately lay down.”  Now maybe I’m not the greatest amateur chemist/biologist/physiologist in the world, but if the effects of mercury are cumulative, and you can’t purge mercury from your system without a doctor supervised chelated treatment, it stands to reason that any amount of mercury is just a slow road to itchyskinville.  But does that mean people living in Hawaii should be evacuated since they are living at the base of a 24-hour-a-day mercury-spitting volcano?

Here’s how the cumulative aspect works.  Similar to the example I gave in Sushi A to Z, The Ultimate Guide, let’s assume there is one part of mercury in the plankton in the ocean.  A shrimp will eat one hundred of these particles inside of the plankton during its life.  A reef fish will eat one hundred of these shrimp, therefore accumulating one thousand particles of mercury.  A tuna will then consume one hundred of these reef fish with the resulting 100,000 units of mercury accumulating in its flesh.  As a result, vegetation and animals low on the food chain are low in mercury, while creatures high on the food chain are high in accumulated mercury. If you want sushi that is relatively mercury free, then you can focus on lower mercury seafood such as abalone, clams, crabs, octopus, salmon, shrimp, squid, or any kind of vegetarian sushi.

I can hear your pleas: “Oh Ross! How, oh how, can we keep eating tuna without taking the same risks as Christopher Walken in a Vietnamese prison camp?”  Well first of all, the studies were focused on bluefin tuna, not yellowfin tuna.  Yellowfin tuna are lower in mercury, mostly due to the fact that they are caught at a smaller size and therefore haven’t eaten as many of their ocean mates as the monstrously sized bluefin tuna have.  Generally speaking, sushi bars prefer to purchase large tuna because it takes less labor to butcher one large tuna into sushi friendly portions than to butcher ten smaller tuna.  If the FDA and EPA are truly concerned about mercury in the seafood supply, restricting the tuna catch to smaller tuna and leaving larger tuna out at sea would not only be safer to the tuna eating population, but then the larger tuna would be free to breed and repopulate the stocks.  This type of program is already in use all over the world with different types of fish. If the tuna industry would adhere to these policies, thinning tuna populations could start bouncing back in a fairly short time. The tuna eating public would be safer from the dangers of heavy metals by consuming the younger, smaller “cleaner” tuna.

So Ross, tell us: what is the bottom line?  Here it is, my daughter (13 years old at this time) and I eat tuna freely.  Raw, canned, you name it, anytime we want, any amount we want, without the fear the mainstream media wants us to feel.  The nation’s tuna fisheries aren’t slowly poisoning you.  Avoiding fish high in mercury is a good idea for women who want to become or are pregnant just for safety’s sake, but the average person doesn’t have much to fear while eating sushi.

Want to learn more?  Try reading http://www.mercuryfacts.org or go to the FDA’s official website.

Copyright 2008 Ross A. Christens