dose of selenium depends on mercury-binding losses

2019.8.26: health/diet/selenium/mercury-binding losses:
2020.1.7: summary:
. selenium (se) is an essential mineral
but it binds to mercury,
and there is a lot of mercury in some foods
especially since the industrial age,
(and some fillings release mercury;
and some flu vaccines may contain mercury).
so some may need more se than others,
ie, you may need more than is recommended.
. some lakes are low in se,
but the ocean has plenty of it,
so most ocean fish have more se than mercury,
however, even if ocean fish are not a
mercury hazard, they still have carcinogenic
endocrine disruptors such as PCB, and dioxins.
. in addition to using sardines for se,
(also omega-3 oils, and plenty of minerals)
I get se from Se-Methyl L-Selenocysteine
since it may have additional benefits
before being degraded into elemental selenium
that can bind mercury and be used in proteins.

Dr.Jockers 2016:
If we have increased mercury consumption
(dental amalgams, vaccines, [polluted food])
then selenium may need to be increased
up to 1000 mcg/daily
in order to compensate for what is lost
from being bound to mercury.
(normally consume between 200-400
micrograms of selenium daily).
. fish is also a great source of selenium.
The key is to use fish sources that contain
significantly more selenium than mercury.

FDA 2019:
. sardines, salmon, anchovies
are best seafood choices;
[that are also available everywhere in cans.]
Eat 2 to 3 servings a week
(For an adult, 1 serving = 4 ounces
For children, a serving is 1 ounce at age 2
and increases with age to 4 ounces by age 11.)

Raymond, PhD; Ralston, PhD. 2004:
Mercury: selenium interactions and health implications.
Measuring the amount of mercury
present in the environment or food sources
may provide an inadequate reflection of
the potential for health risks
if the protective effects of selenium
are not also considered.
. not only does selenium have an effect on
mercury’s bioavailability,
but mercury may also have an effect on
selenium bioavailability.
Mercury’s propensity for selenium sequestration
in brain and endocrine tissues
may inhibit formation of essential
Se-dependent proteins (selenoproteins).
Hence, selenium’s ‘protective effect’
may simply reflect the importance of maintaining
sufficient free selenium to both bind mercury
and also support normal selenium-dependent
enzyme synthesis and activity.
To our knowledge, there are no reports of
mercury exceeding selenium concentrations
in any ocean fish.

Univ N Dakota 2011:
. while all ocean fish are selenium-rich,
the selenium in freshwater fish
may be limited in certain regions.
[thus beware farm-raised ocean fish,
as they may not be raised in oceans]
table of nutrients in
4-oz seafood from oceans:
(grams DHA and EPA, micrograms selenium):
pacific oysters:
1.5, 170;
Anchovies, Herring, and Shad:
2.3..2.4, 50..75;
sardines:
1.1..1.6, 40..60.
. the 21st amino acid, selenocysteine.
This amino acid is unique from the other
20 amino acids in that it contains selenium
and it is required as the active component
of selenoproteins, needed for
at least 20 very important enzymes.
. selenocysteine is the only amino acid
that must be degraded and reformed
during each cycle of selenoprotein synthesis.
Selenide is released from selenocysteine
when it is degraded, making it vulnerable to
binding with heavy metals such as mercury.
Once bound to mercury, selenium is
no longer available for selenoprotein synthesis.