"Is Fish “Brain Food” for Older Adults?"
In the landmark Global Burden of Disease study,
they compiled the top 20 causes of death and disability.
Number one on the list was high blood pressure,
two and three are smoke.
The number four leading cause of loss of life and health
was not eating enough fruit.
Lack of exercise was number ten,
then too much sodium,
then not enough nuts and seeds,
not enough whole grains, not enough vegetables,
and number 18 was not getting enough long-chain omega-3 fatty acids
like EPA and DHA found in seafood
due to their purported protective effect against heart disease.
Even years ago when this was published however,
they were already questioning the benefits of these fish fats
as more and more randomized controlled trials
put them to the test and they failed,
culminating in the recent meta-analysis,
that I profiled previously
that appeared to put the issue to rest.
Cardiovascular protection isn’t the only thing
fish and fish oil consumption was hyped for, though.
Omega 3’s have also been touted to treat depression,
but after taking into account all the negative results
that went UNPUBLISHED, there appears to be no benefit
for major depression or for preventing suicide,
as I explored previously in my video
on fish consumption and suicide.
But what about for the prevention
of cognitive decline or dementia?
The available randomized controlled trials show no benefit
for cognitive function for omega-3 supplementation
in studies lasting from six months to 40 months
among healthy older adults.
It may sometimes even make things worse.
Higher current fish consumption
predicted WORSE cognitive performance
and greater PAST fish consumption in childhood
predicted slowed perceptual speed and reaction time.
This may be due to neurotoxic contaminants in fish,
such as mercury.
We’ve known that the developing brain
is particularly sensitive to the damaging effects of mercury,
but maybe the aging brain is as well.
This would explain results like this,
where higher Omega-3 levels were associated
with high levels of cognitive impairment and dementia.
More EPA found in the cognitively impaired
and more DHA found in the demented,
presumably because of pollutants like mercury
and PCBs in seafood that have been related
to cognitive impairment or Alzheimer’s disease.
The same cognitive functions disrupted in adults, like attention,
fine-motor function, and verbal memory,
are similar to those previously reported
in children exposed in the womb.
And the adults exposed to mercury through fish consumption
didn’t just have like subtle EEG brain wave changes or something,
but observable deficits
in neurobehavioral performance measures,
for example poorer performance on tests
of fine motor speed and dexterity, and concentration.
Some aspects of verbal learning and memory
were also disrupted by mercury exposure,
and the greater the mercury levels the worse they did.
But look, this study was done downstream of a gold mining operation,
a process that uses lots of mercury.
Other such studies were done on people eating fish
next to chemical plants or toxic spills
or eating whale meat.
What about a more mainstream population?
In fact, an elite group of well-educated participants,
really well educated—
most were corporate executives like CEOs,
all living in Florida,
and wealthy enough to afford so much seafood
that at least 43% exceeded the EPA’s safety limit for mercury.
And it had an effect.
Excessive seafood intake, which they defined
as like more than three or four servings per month
of fish like tuna or snapper,
elevates mercury levels and causes cognitive dysfunction.
Not much-only about a 5% drop in cognitive performance,
but a decrement that no one,
let alone a health conscious
and achievement- oriented person,
is likely to welcome.
It’s worth noting the irony of the situation.
The fact that corporate executives who choose to over consume seafood
for health reasons instead sustained a DROP
in their executive functions as a result.
Yet, if a 4.8% drop in executive function
due to excessive seafood intake
occurs in highly functioning, healthy adults
with ample cognitive reserve,
the major concern is whether similar mercury level elevations
in individuals already suffering from cognitive decline
might result in substantially greater declines,
particularly with cognitive decline, dementia,
and seafood consumption on the rise.