Sunday, May 24, 2015

Risk of Eating (or NOT Eating) Fish

If your mother was like mine, eating fish was a good thing.   She called it “brain food” and all we kids wanted to be smart so we would eat fish even if we did not like it.

Things have changed; eating some types of fish can presumably put your brain at risk.  Mercury, a neurotoxin contaminant in fish, comes to mind (no pun intended).   A 2004 FDA web site (still viewable online):  advises us to NOT eat:

·         Shark
·         Swordfish
·         King Mackerel
·         Tilefish

This same web site advises to only eat limited amounts of tuna.

Predatory fish are relatively high on the food chain and toxic contaminants tend to bio-accumulate up the food chain such that these higher-ranked species have higher levels of mercury.   Of course, we all know who is at the top of the food chain!

Then there is the additional risk of cancer, again from eating fish that are relatively high on the food chain for the same reason; that is, accumulation of potentially cancer causing toxicants in the fish.
So what is a person to do?  If you hate fish, it is good excuse for avoiding it but that avoidance is not rational. 
I found an excellent web site that puts a lot of this into context:
I found the following quote from this site:
“Again and again, research shows that people eating diets with a moderate amount of seafood have lower risk of cancer and other chronic diseases and longer lives.”

It goes into some detail as to why this is the case but it makes the excellent general point:  Almost all risk as attended with some benefit.    Often the benefit clearly outweighs the risk.

Black and white thinking is generally not useful and this is particularly so in the realm of risk assessment and risk management.   If exposure and risk to unacceptable levels of a substance is occurring then clearly some risk management action needs to occur to reduce or eliminate that exposure.  If it is not practical to reduce the exposure then exposure to that substance should be eliminated.   Elimination should only happen when there is no other reasonable alternative. 

We all need to remember that the risk of death in this life for everyone is 10or ONE.  Something is going to get each and every one of us.  Our job as rational beings is to pick and choose what risks we are willing to accept along with the benefits they provide.   That means doing the best job we can at risk assessment.

In conclusion, eat your fish!


  1. The FDA web site also has a more recent risk-benefit analysis:

  2. Is it accurate to assume that warm water fish are low in omega-3 fatty acids? For example, I will not eat Tilapia, a brackish water fish that can live on algae and is low in omega-3 fatty acids. I've even seen aquaculture where a species such as Trout is raised, and then Tilapia is brought in to clean up the water, including excrement. I also believe I can taste the difference between farm raised and wild-caught salmon.

  3. About 5 years ago, I used to be an inveterate fish eater towards healthy life habits and so fish had replaced red meat on my meals. Suddenly I was feeling terribly exhausted, sleeping frequently and continously, including irregular heartbeat, high blood pressure and muscular fatigue symptoms. My cardiologist was treating me as if I was suffering from stressful work. One night I was watching a David Letterman's show when a guest told him he was suffering from those same symptoms and like me used to have fish as his main food and as a result was poisoned by mercury from fish. I rushed for blood testing which result accused 35.8 mcg/l for mercury against 9.9 mcg/l normal upper limit. After 3 months of treatment with EDTA, dosage levels returned to normal. Today I have no more Hg poisoning symptoms, eat fish only one time a week and just species farm raised in clean water like tilapia and salmon.

  4. Glaucio, thank you very much for sharing this. It is truly a cautionary tale about eating too much fish. What we have done to our own natural environment in this case is a shame.

  5. Interesting story from Glaucio. Indeed, "ne quid nimis" or nothing to excess provides a useful guideline to most things.
    Michael Connor