images-6 fullscreen

The Truth About Toxic Mercury in Fish

Hey, guess what I found out.  Most people do not eat enough cold-water, fatty fish, and this is especially true of pregnant women.  Everybody is worried about mercury toxicity.  I was.

Believe it or not these worries are not supported by science the majority of the time.  In fact, it is much safer to eat fish than it is not to eat it!

DHA is a crucial nutrient for the development of the brain and the nervous system and is derived from eating, you guessed it, fish!

Eating plant sources of omega-3 like flax and walnuts doesn’t cut it. Only a very small percentage of the short chain omega-3 fats found in plants (1%) gets converted into the beneficial long-chain omega-3 fat DHA.

How Does Mercury Cause Problems?

You see, mercury binds with selenium and causes a lack of selenium. Without selenium, vitamin C can’t perform its functions, and then oxidative damage (the cause of many serious diseases) is  going to happen fast and furiously!

What I want you to understand is that the ratio of mercury to selenium is the key to the problem. Our soil, here in the U.S. is rich in selenium, this is a very important component. In other countries where selenium is poorly available, mercury exposure is much more dangerous.

Most ocean fish and even most fresh water fish have plenty of selenium, much more selenium than mercury averaging 20:1 (except whale and shark meat which contain an excess of mercury).

Mercury is the only thing we know of that can kill selenoenzymes. (enzymes made from selenium)

Bottom line: As long as you have more selenium than mercury you are in good shape.

Studies have shown that the benefits of eating ocean fish during pregnancy amount to as much as 5 IQ points to the developing fetus!

So the more ocean fish moms eat during pregnancy the more selenium, omega-3 fatty acids and vitamin D are taken in.  They are known to be hugely important for developing healthy brains as well as contributing to the mother’s health during and post pregnancy.

Eating more fish is actually good advice for women. Too many people have misconceptions. People need to know ocean fish need to be eaten in greater amounts! Dr. Ralston recommends eating fish 2 to 3 times per week.

So here’s a great way to start, with my Eden Crusted Salmon recipe mmmmmm.



This information was taken from an interview on, with Dr. Nicholas Ralston.

Dr. Nicholas Ralston is a research scientist at the University of North Dakota Energy and Environmental Research Center, EERC, involved in evaluating potential human health effects and risks resulting from environmental exposure to air toxics.  He received his PhD in biomedical research biochemistry from Mayo Medical Center and his bachelor’s of science in biology from Mayville State University.  Dr. Ralston’s principal areas of expertise include the biochemistry and analytical approaches to quantitative assessment of immune research and inflammation at the molecular and cellular level.  His primary interests are in trace element physiology and the pathophysiology of toxic trace element exposures as well as prevention, protection, and remediation strategies.  His current research interests include examinations of the molecular mechanism of methylmercury toxicity, selenium-dependent biochemical processes involved in preventing the neurotoxic effects of mercury, mechanisms of pulmonary particulate pathologies, mercury phytoremediation, and other means of diminishing bioaccumulation of mercury in fish.

Prior to his position at the EERC, Dr. Ralston worked at Grand Forks Human Nutrition Research Center and Bowman Gray Medical School at Wake Forest University.  He has authored or coauthored over 50 professional publications, research articles, and book chapters and given numerous invited presentations on health issues related to methylmercury-dependent inhibition of brain selenoenzymes and beneficial effects of maternal seafood consumption on child development outcomes.

Sign up to get FREE tips to create a life you love!
It's free!


  1. murray dweck
    March 8, 2013 at 2:47 pm ·

    Hi Joy,
    My granddaughter Claudie reach out to me regarding your blog, “The Truth About Toxic Mercury in Fish”, because she knows I limit my fish consumption to wild alaskan salmon. So I read the Dr. Nicholas Ralston interview and it sounded pretty good.
    I then wanted to verify his conclusions with one of my doctors,
    Walter J. Crinnion ND. He is a highly respected expert in the field of environmental medicine. ( I first met DR Crinnion, about 10 years ago when I spend a week at his clinic in Seattle with my partner and my son to learn how to detox )
    I forwarded the interview and here is his response:
    Hi Murray,
    I hope you are well. He writes a pretty good article, but makes some factual errors.
    Eating fish that is high in mercury not only NEGATES the cardiovascular benefits of fish oil but actually INCREASES the risk – this was just published. This shows how powerful of a cardiovascular toxicant that mercury is. This includes fish with high mercury and high selenium (and selenium helps the heart also).
    He also misses it on PCBs and other persistent pollutants. Farmed carniverous fish is the HIGHEST source, along with freshwater fish from contaminated waters (think the Great Lakes). The next highest source (far lower than these fish) is non-organic butter. Beef is lower than that.
    He then uses cancer incidents for PCB health effects. While they have been associated with cancers, they are more associated with adult onset diabetes, obesity, fatigue and immune abnormalities.
    His info on selenium is selective and he promotes a theory that doesn’t really fit clinical reality.

    Walter J. Crinnion ND
    Chair, Environmental Medicine Department
    Southwest College of Naturopathic Medicine

    You have a great web site.

    Shabbat Shalom,


  2. claudie
    January 25, 2013 at 1:21 pm ·

    how about supplementing with high quality cod liver oil? im getting nervous i dont feed my kids enough fish, but i do give them carlsons cod liver oil.

    • Joy Harari
      February 11, 2013 at 4:53 pm ·

      I give all my clients fermented cod liver oil. Green Pastures makes a great one!