Mercury From Fish Can Affect Cognitive Function in Middle Aged Adults

In reviewing the latest information about mercury and cognition, I became aware of an article that appeared in the Integrative Medicine Journal a year ago.

To study looked at 384 men and women who were mostly corporate executives and who attended an all day company annual physical examination.

They measured the blood mercury levels in all the patients and then looked at the relationship between mercury and cognitive performance in the patients.

The finding was that participants with Mercury levels above 15 mcg/L,showed a 4 to 5% lower complex information processing (CIP)capability, which is commonly called executive function, when they did neurocognitive testing.


The interesting thing from the study was that in those patients with moderate fish consumption, 1 to 3 servings of fish per week, there was no measurable effect on their cognition. This was thought to be caused by the fact that the fish contain essential fatty acids which can improve cognitive function. Therefore the deleterious effects of the mercury were compensated for by the fatty acids in the fish.

The authors rightfully point out that “If cognitive neurotoxicity occurs in healthy, highly productive individuals with ample cognitive reserves, the effect is likely to be amplified in more vulnerable populations.”

They point out that cognitive decline and dementia are an increasing problem as our population is aging. Therefore as seafood consumption also rises in individuals who desire to eat a “heart healthy” diet, this relationship with increased mercury could have a large impact on quality of life, and healthcare costs into the distant future.

This is one of the first studies I’ve seen that actually looks at the effect of mercury on cognitive impairment in middle-aged people. The drawbacks of the study are that that they only looked at one blood specimen and compared it with the patient’s stated history of fish consumption. There is no measurement of mercury exposure over time in the patients.

An even bigger question is what were these patients “Total Body Load” of Mercury? This can only be determined by doing a challenged urine test, with a chelating agent.

What the authors do not point out is that after a person eats fish, the mercury is not eliminated from the body but rather goes into the organs, muscles and tissues of the body where it is stored for the rest of the person’s life! This burden of mercury produces a chronic stress on the neurological, immune, and endocrine system.

In my opinion, this total body burden plays a role in a wide range of diseases from multiple sclerosis to cancer.

The other thing the authors do not point out is that the amount of essential fatty acids contained in each fish serving could be replaced by one Eseential Fatty Acid capsule from the health food store.

My general recommendation to my patient population is still to avoid or minimize fish consumption and take one essential fatty acid pill per day.

Certainly women of childbearing age and women who are pregnant should avoid fish altogether in my opinion. Of course they must take one pill a day of DHA, an essential fatty acid, for their fetuses brain function, along with their traditional Prenatal Vitamin.

I predict that as the oceans increasingly concentrate more and more mercury, and the fish get higher and higher levels of mercury in them, that we will see much more about this in the years ahead.

Read the original article here

Read the whole article here

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Long term neurocognitive impact of low dose prenatal methylmercury exposure

Fish consumption, methylmercury and child neurodevelopment

Let me know what you think below!

About Dr. Soram Khalsa

As an MD, Dr Soram specializes in Integrative Medicine combining diet, nutrition, acupuncture, herbs and nutrition. Visit Dr Soram’s Healthy Living Store where you’ll find high-quality nutritional supplements: