The mercury debate

Recently for my biology class I had to look at 3 different websites (,, with varying positions on the issue of mercury levels in the fish we eat and write up a paper on my findings. I really enjoyed the assignment and figured I’d post it here. This was not a MLA format type of research assignment so I was able to have fun with my format.

The case against fish consumption

There are many groups that argue that eating fish with high levels of mercury is hazardous to your health. It is presented as a “wide spread public health” problem and consumers are encouraged to petition the FDA to take action against distributors of high mercury-containing seafood. Mercury is toxic. Mercury activist groups argue that eating too much seafood can cause an increase in mercury levels in the blood and lead to mercury poisoning. Effects of mercury poisoning include brain fog, hair loss, bloating, weakness and reddening of the skin. It is especially important for women and children to avoid exposure to high levels of mercury because of the effects they can have on brain development of fetuses and young children.

The case for fish consumption

Fish meat is low in fat and a good source of protein. Fish is also high in Omega-3 fatty acids which are great for brain-health and also fight disease and cancer. The pro-fish consumption advocates argue that the health benefits of eating fish far outweigh the risks of mercury poisoning and that people should probably be eating more fish. A good point on this side of the argument is that selenium, a molecule that binds to mercury making it difficult for the body absorb, is also plentiful in fish. Science shows that the presence of selenium does block absorption of a portion of the mercury we eat, potentially canceling out the toxicity associated with mercury levels in fish.


It is important to note that both sides of the argument have special interests backing their causes. Groups against eating more fish express concerns with over-fishing and fishing practices that are detrimental to other wildlife. Mercury is naturally occurring in the environment but more gets introduced as chemical waste products are dumped into the ocean and as fossil fuels are burned. The mercury calculator on the gotmercury website appears is sponsored by the movie “The Cove” which is a film made in protest against the slaughtering of dolphins for food in Taiji, Japan. There are many reasons to oppose dolphin slaughter but one of the major arguments is that the high levels of mercury in dolphin meat are harmful. The same website also talks about the harm to already threatened sea-turtles from the fishing industry. There appears to be more of a concern over the impacts of eating fish to the environment than the impacts to human health.
Likewise, if you click the about us link on the mercuryfacts website you will see that it is a project of consumer freedom. If you go to consumer freedom’s website and click on their about us link you can scroll down and see that the non-profit is funded by restaurants and food companies. I would take this to mean that mercuryfacts was probably sponsored big food, which is against regulation that could impact their “bottom line.” The mercuryfacts website also, almost irrelevantly, defends high-fructose corn syrup, which apparently has been shown to have trace levels of mercury in it. Corn syrup is a simple sugar made from corn. Corn is subsidized by the government meaning that the government will give farmers money to produce corn, therefore making corn a very profitable crop and corn syrup a very inexpensive sweetener to use in most foods. Big food also has a vested interest in defending corn syrup because it is much cheaper than cane sugar.

What the EPA/FDA has to say

I think the EPA/FDA position is summed up pretty well in their message to consumers: “Fish and shellfish are important parts of a healthy and balanced diet. They are good sources of high quality protein and other nutrients. However, depending on the amount and type of fish you consume it may be prudent to modify your diet if you are: planning to become pregnant; pregnant; nursing; or a young child. With a few simple adjustments, you can continue to enjoy these foods in a manner that is healthy and beneficial and reduce your unborn or young child’s exposure to the harmful effects of mercury at the same time.” Their website seems to represent both sides of the argument pretty well. They acknowledge the dangers of high mercury levels and recommend avoiding shark, swordfish, king mackerel and tilefish. However, they also acknowledge that fish and shellfish can be an important part of a healthy diet and recommend 2 meals of low-level mercury seafood a week and if you are going to eat canned tuna it is best to eat chunk-light tuna. For locally caught fish mercury levels depend on local conditions. It is recommended that people check local advisories and limit their caught-fish consumption to 6oz a week.
Both the mercuryfacts website and the EPA website make the distinction between the mercury found in thermometers and the methylmercury in fish. My own research found that methylmercury, a byproduct of coal burning that gets released into the atmosphere and accumulates in our oceans, is the more toxic of the two.

My opinion

I like to eat fish. I do not eat enough of it to be worried about my mercury levels. I eat, on average, the recommended 2 meals a week and it is mostly in the form of chunk-light canned tuna, with the occasional shrimp or frozen fish products (fillets, fish sticks). I think that my tuna lunches likely bump my fish consumption to slightly more than the average Joe. The point of all of this is that I don’t believe most Americans eat enough fish, let alone swordfish or the other flagged varieties for this to even be a major concern. I think the information is good to know but I do not believe it should be made out to be the “epidemic” that the activists push for.
I do care about the issues the activists put forth like over-fishing, threats to sea turtle populations and dolphin slaughter. I do not agree with them painting their motivations as a concern for public health when they are clearly more concerned about the environment. Similarly I do not appreciate big food’s fake concern for my health when they are the ones profiting off my decision to eat fish.
I chose not cite research studies by either side because of the potential for bias. When special interests fund research they often set up experiments in a way that will produce results supporting their side of an argument.
I like the EPA/FDA’s middle ground approach.  “Everything in moderation” is a rule that applies to almost every area of life in my opinion. Fish meat does have a lot of health benefits and I believe everyone should make an effort to include it in their diets if they don’t do so already. I also believe that people should be aware of the fishing industry’s threats to the environment and of the potential health risks of increased mercury intake.

2 thoughts on “The mercury debate

  1. You might want to look at mercury in the new “Ecology Friendly” light bulbs we all have to use now.
    A little more dangerous than eating fish.
    I blogged about it, but you can find a lot of information on the web.
    And… everyone has an agenda, shy of doing your own research into everything, we’re all pretty much at the mercy of what we’re told. Read lots, think lots.
    Nice read, thanks!

  2. If you have silver fillings then you will have a higher amount of mercury in your body in three ways. Mercury is inhaled, it dissolves in your saliva and it goes through your tooth into your jaw bone . Www.

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