Global Health Asia-Pacific July 2020 July 2020 | Page 21

bioaccumulates in fish and shellfish and biomagnifies.
This is why large predatory fish are more likely to have
high levels of mercury because they eat smaller fish
that have acquired mercury through plankton.
��eople may be exposed to mercury in any
of its forms under different circumstances,� says
the World Health Organization in an advisory on
mercury. �However, exposure mainly occurs through
consumption of fish and shellfish contaminated with
methylmercury. Cooking does not eliminate mercury.�
�o do the health benefits of eating fish outweigh
the potential risks�
All humans are exposed to mercury in their daily
lives, with most of us encountering low levels through
the environment.
�oetuses are most susceptible to the harmful
developmental effects of mercury. Exposure can result
in impaired cognitive thinking, memory, attention,
language skills, and fine motor and visual spatial skills
in childhood.
Also highly vulnerable to high levels of mercury
are populations who rely on subsistence fishing,
according to the WHO. It noted that among certain
subsistence fishing populations between 1.5 of 1000
and 17 of 1000 children showed cognitive impairment
(mild mental retardation) caused by the consumption
of fish containing mercury.
In a 2016 study on whether mercury accumulation
from regular fish consumption had any connection to
Alzheimer’s features like protein plaques and tangles,
the late Rush �niversity epidemiologist Dr Martha
Clare Morris found that people who ate seafood at
least once a week showed higher levels of mercury in
the brain than those who ate less.
�ut for people with one genetic risk factor for
Alzheimer’s, called ApoE4, which affects about a third
of the population, eating more fish also showed lower
amounts of harmful proteins in their brain.
Dr Morris’ landmark research provides
reassurance that mercury accumulation from
moderate seafood consumption is not related
to increased brain pathology, according to Dr
Edeltraut �roger, a �aval �niversity population
health researcher and co-author of an editorial to
accompany the Rush study.
�This research has come as a relief to people
who were concerned about eating seafood because
of its mercury content since it showed no evidence
that increased levels of mercury in the brain causes
brain pathologies,� Dr �roger told Global Health Asia-
�acific.
�This is particularly encouraging, given a
lack of evidence on protection against many
neurodegenerative diseases including Alzheimer’s.�
However, this does not mean that mercury
contamination from fish consumption is not without
risk. Other studies have linked mercury exposure to
not only cognitive impairment but also high blood
pressure, an increased risk of heart attacks, and
higher �bad� �D� cholesterol.
The bottom line is that you should eat a variety of
fish in moderation and choose those that are low in
mercury contamination, while avoiding higher-mercury
species.
Also highly
vulnerable to
high levels of
mercury are
populations
who rely on
subsistence
fishing,
according to the
WHO
Landmark research provides reassurance that mercury accumulation from moderate seafood consumption is not related to increased brain pathology
GlobalHealthAndTravel.com
JULY 2020
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