It's amazing how even though this information gets published nationally, people usually continue their destructive life-style, then wonder why they are dying prematurely and of horrible diseases.  Repeatedly we have heard how fish is good for us in many ways.  But concern is rising about seafood lovers consuming high doses of mercury and the illnesses it causes. A study in San Francisco discovers high levels of toxic methyl mercury found commonly in blood and hair samples of men, women, and children.  Many were already suffering low level toxic symptoms of hair loss, fatigue, depression, difficulty in concentrating, headaches, and other neurological symptoms.  Environmental Health Perspectives, a journal of the National Institute of Health (NIH) and the FDA advisory committee, recommended in July to research the risks related to canned tuna.  Of course, more research, more money, but what about the nation's health?  I am not encouraged at all by the concerned role playing.    
Tuna is the most consumed fish in the U.S. and the mercury in one can averages to about 0.17 parts per million. Doesn’t seem like much, but if you're pregnant and consume over two cans per week, you exceed safe levels of mercury.  This is a huge concern for pregnant women because the fetus has the most inert cells of the mother’s body. This is where most of the toxins would go.  The FDA recommends a limit of 12 ounces per week.  We know their limits are not really safe limits!  
Mercury released from power plants, municipal waste facilities, and medical incinerators is the primary source of methyl mercury in fish.  Methyl mercury is an organic form of mercury that is different from the mercury in thermometers or what goes up smokestacks when coal is burned.  
Mercury is converted to methyl mercury by bacteria in water.  Amalgams, or metal fillings in teeth, are converted to methyl mercury by the bacteria in the human body.  So, when people are talking about mercury in fish, they’re really referring to toxic methyl mercury. It's danger to health is that it is hard for the body to eliminate, so it builds up and affects the nervous system.  Most humans are exposed to methyl mercury in fish consumption and metallic fillings in the teeth.  Studies show 45% to 55% of the metal alloys in teeth are mercury.  When a person clinches their teeth or chews food, methyl mercury is released, inhaled, and digested.  
The FDA ceased its "Large enough for mercury" sampling program in 1998, and today Federal agencies conduct only limited testing of fish for methyl mercury.  We do know that tuna contains methyl mercury. Studies show women ages 15 - 44 eat canned tuna 1.5 times a month, which is within FDA safety levels.  However, any level of the toxic chemical affects the human body and over time accumulates, resulting in serious complications, chronic disease, and sometimes death.  
The EPA has a reference dose that says people can be exposed to 0.1 micro gram per kilogram of body weight per day, which is roughly 5 to 7 micro grams per day for someone who weighs 100 to 154 lbs.. 
That’s about a 20% of the amount the FDA considers safe. 
Fish that may have high levels of mercury are swordfish, shark, tile fish, King mackerel, and tuna.  Fish that generally have lower levels of mercury are salmon, flounder, cod, catfish, trout, Pollock, clams, shrimp, scallops, and lobster. 
Please note that the Bible has always described what is healthy and not healthy to eat.  Science is now discovering what God’s word has always said: only eat fish with scales and fins.  The fish listed above like catfish, clams, lobster, etc., are not healthy choices.  
According to Washington State’s Department of Health, 
the amount of canned tuna that is safe to consume per week
should be based on body weight:
25 lbs.= 1 tbsp.
50 lbs.= 2 ounces
75 lbs.= 3 ounces
100 lbs.= 5 ounces
125 lbs.= 6 oz (=one can)
150 lbs.= 8 ounces 
175 lbs.= 9 oz.
200 lbs.=10 oz..
Albacore chunk or chunk light varieties have less mercury 
than solid wide or chunk white types. 
You can read more on this subject in USA Today’s cover story from
Tuesday, November 5, 2002 issue.
Image source: Wikimedia Commons