Omega-3 Fatty Acids and Mercury Co-exist in Fish

at 2:18 PM

Fish are not only great sources of proteins, vitamins and minerals but their fat is largely unsaturated and is high in omega-3 fatty acids,particularly the ones abbreviated as DHA and EPA.  Research (supportive but not conclusive) has shown that these fats (along with omega-6 and omega-9 fatty acids) protect against heart disease.  Mercury is a naturally occurring heave metal that is best knows for its presence in the old thermometers (I have broken one or two out of curiosity).  This element is emitted from coal-burning power plants and it falls from those emissions into nearby fields and bodies of water.  By it self, mercury is not toxic, in fact you do not absorb a lot of it from your digestive tract, BUT, when mercury gets in water, micro-organisms 'methylate' it and so it is gets converted to methyl-mercury which is absorbed quickly by the human body.  So the bottom line is all fish is contaminated with methyl mercury (which is very dangerous for the developing fetus).

 "Avoiding it is simple enough, but like much else about fish, the methyl mercury dilemma is inevitably complicated by politics". (What to Eat by Marion Nestle)

The FDA issued its first advisory in 1994 about methyl mercury in fish.  The agency said that methyl mercury could be highest in predatory fish (high up in the food chain)- including shark, swordfish,and albacore tuna.  The cheaper 'chunk light' tuna does not have as much methyl mercury as albacore, but the fish industry did not want to single out albacore.  Why? Since most people can't differentiate between various types of tuna, the fish industry worried that by singling out albacore, consumers would avoid tuna altogether.

Bottom line? You would have to be a molecular biologist, a fish lobbyist and read the latest data on this stuff to make the best decision, but short of that... you are safe eating fish two to three times a week.  But if you want to stay away from fish altogether, there are other sources of omega-3 fatty acids such as chicken and eggs.  Also beans, nuts and seeds contain this wonderful fat. 

Finally put all of this in perspective.  Omega-3s are not the only things that are good for the heart; so are vitamins and minerals and what else? Yes, you guessed it: exercise.

But did you know that the richest source of omega-3s is caviar?