Index Home About Blog
From: ((Steven B. Harris))
Subject: Re: selenium
Date: 18 May 1995
Newsgroups: sci.life-extension

In <1068@ceri.win.net> fowkes@ceri.win.net (Steven Wm. Fowkes) writes:

> Selenomethionine must be
>catabolized (broken down) to release free selenide in order to
>incorporate selenium into glutathione peroxidase. Selenomethionine is
>treated like methionine by the body.  Selenomethionine is incorporated
>into proteins just like methionine, and it tends to accumulate in
>proteins. This causes cummulative toxicity.

Wups, no, this is the old view.  It is now known that there is a special
codon at the site of selenomethionine in both DNA and RNA for proteins
like glutathione peroxidase and the thyroid inner ring deiodinase, which
incorporate this amino acid at an active site.  Thus, selenomethionine
is NOT a post translation modification to proteins, but rather is a 21st
amino acid specified by the RNA code, with its own special transfer RNA.

   There is some evidence that selenomethionine gets incorporated into
other proteins at (I believe) serine sites, so this system may not be
perfect (this codon also codes for serine).

                                            Steve Harris, M.D.





From: sbharris@ix.netcom.com (Steven B. Harris )
Subject: Re: Poisonous Plants (Inorganic Poisons)
Date: 26 Jul 1995
Newsgroups: sci.bio,rec.food.cooking,sci.med.nutrition

In <dylanyDC78B8.1vA@netcom.com> dylany@netcom.com (Dylan Yolles)
writes:

>klier@cobra.uni.edu wrote:
>> Sure.  Certain species of Oxytropis and Astragalus ("locoweeds")
>> concentrate selenium-- actually they incorporate selenium into amino
>> acids in the places where ordinary plants and animals use sulfur-- the
>> so-called "sulfur-sparing metabolism".  Se and seleno-amino acids are
>> pretty good mammalian neurotoxins.
>
>I have a bottle of vitamins here which contain 10 mcg of Selenium in the
>form of Selenium Selenite. (In fact - they come from Trader Joe's.)
>Should these be avoided?



Inorganic selenium is not too poisonous, and you can take 250 mcg
forever without danger.  Apparently you can even take 1000 mcg a day
with risking nothing more than bad breath and a garlicy sweat.  5000
mcg (5 mg) a day and up is considered poisonous.   However, I've read
stories of selenium workers at rectifier plants who had so much
selenium in them that their fingernails turned red from crystals of the
reduced element under the nailbed.  So some people can tolerate a LOT
of inorganic selenium.  The organic amino-acid stuff is another matter,
possibly.

                                         Steve Harris, M.D.




From: mannj@southern.co.nz (Jay Mann)
Newsgroups: sci.med.nutrition
Subject: Re: Modern soils depleted of vitamins?
Date: 19 Nov 1997 18:26:37 GMT

Ian Woollard (wolfe@nojunkmail.nortel.co.uk) wrote:
: Jay Mann wrote:
: > Since plants in general require similar minerals to those needed
: > by animals, a depleted soil would be a poor-yielding soil.
:
: That's somewhat true, but there are some big exceptions. One
: notable exception is selenium. Plants don't need selenium to
: grow at all- animals most definitely do.

Most plants don't, but some Astragalus species require selenium, and have
accordingly been used as bio-markers for high-selenium soils.  I think these
species are toxic to grazing animals because of their selenium content.


: There is a very high negative correlation between the level
: of selenium in the soil of different countries and the level
: of breast cancer in those countries. (Not that that is the
: whole story, but selenium does appear to protect against
: this disease.)

Here in NZ where we have naturally low-selenium soils, a muscle-wasting
disease of sheep is prevented by "drenching" the animals with selenium
supplements.  (A "drench" is not necessarily a bath, and in this case is a
squirt of liquid into the animal's mouth.)   In one region of China, where
children in their teens were dying of heart attacks, selenium
supplementation almost completely stopped these problems.  Again, this shows
a connection between muscles and selenium.  You won't be surprised that
selenium pills are fairly popular here among city folk who don't have access
to sheep drench.  Otherwise it's too risky: if you eat bread made from NZ
wheat, and don't eat seafoods, you might not be getting enough selenium.
But if the bread flour came from Australian wheat, you're ok.  Why take a
chance?



: Areas that are low in selenium include the UK, Canada (and as
: far as I can recall the US.)

One region of China, Finland, and the South Island of New Zealand are, I
think, the prize winners for low-selenium soils.  In Finland, farmers are
required to treat their soils with selenium.

Jay



From: mannj@southern.co.nz (Jay Mann)
Newsgroups: sci.med.nutrition
Subject: Re: what is the use of sernium in human body?
Date: 4 Dec 1997 19:36:07 GMT

Chairo (bc_lmf@uxmail.ust.hk) wrote:
:
: 	sernium is a minor mineral for human body....but what's it usage?

I think you are referring to selenium.  My bottle of selenium supplement
contains 100 micrograms (that's 0.1 milligram) of selenium.  Unless you live
in the selenium-deficient province of China (don't recall its name) you
probably don't require any supplementation.  And since HongKong is famous
for its seafood restaurants, where seafood is rich in selenium, that's yet
another reason not to be concerned.

I take selenium because New Zealand soils are deficient in selenium, which
means locally grown wheat is also deficient.

Jay D Mann  <mannj@southern.co.nz>
Christchurch, New Zealand



From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med.nutrition
Subject: Re: what is the use of sernium in human body?
Date: 5 Dec 1997 00:08:28 GMT

In <6670n7$t73$1@mnementh.southern.co.nz> mannj@southern.co.nz (Jay
Mann) writes:
>
>Chairo (bc_lmf@uxmail.ust.hk) wrote:
>:
>: 	sernium is a minor mineral for human body....but what's it usage?
>
>I think you are referring to selenium.  My bottle of selenium supplement
>contains 100 micrograms (that's 0.1 milligram) of selenium.  Unless you live
>in the selenium-deficient province of China (don't recall its name) you
>probably don't require any supplementation.


    On the contrary, a recent study in which Americans were randomized
to either 200 mcg a day or placebo showed a 50% reduction in many nasty
cancers, including prostate cancer.  That's quite a useful thing, to be
able to decrease your major cancer risk by 50% just by taking a pill.

                               Steve Harris, M.D.


	[[ Note: Since this was written, the selenium / cancer link has
	   been studied in a huge trial, and seems not to be significant;
	   see the SELECT trial homepage at:

		http://www.crab.org/select/

			 -- Norman ]]

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med.nutrition
Subject: Re: what is the use of sernium in human body?
Date: 6 Dec 1997 12:31:43 GMT

In <3488EC60.29CC@erols.com> physical@erols.com writes:
>
>	But China is where most of the selenium toxicity studies have been
>done, due to their HIGH selenium content.  I suppose some areas are
>deficient also.


    Yep.  The region of Keshan, for instance.  People there get a
characteristic cardiomyopathy, which is probably due to an inadequate
immune response to a particular virus which causes cardiomyopathy if
not dealt with effectively.  It's not strictly a selenium effect on the
heart at all, but rather on the immune system.

   Which is not surprising, since in animals selenium deficiency to the
point of causing pathology is extraordinarily hard to produce (you need
to be vitamin E deficiency also), and usually involves the liver, not
the heart.  And, of course, spontaneous cancer incidence goes up.

                                  Steve Harris, M.D.



From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med.nutrition
Subject: Re: selenium(200mcg) info?
Date: 14 Jun 1998 06:35:58 GMT

In <35811ed7.3118677@nntp.uio.no> alf.christophersen@basalmed.uio.no
(Alf Christophersen) writes:

>"EricP" <EricPsor@usa.net> wrote:
>
>>I weight about 140 lbs plus/minus 5 lbs, so it would translate to
>>about 305-325 mcg/day max. for my case. Are there any foods
>>(especially vegetables and fish) that contains more than 100 mcg of
>>selenium? In other word, what food sources that are rich in selenium?
>
>
>Depends on where you live and from where your food comes.
>
>There are areas in US that has almost as low Se content as in Europe,
>while others are very rich in it, and some few places so high that the
>content may be chronically toxic. Other places in world it may even get
>up in acute toxic doses.


   Yes, though in these days of refrigeration and world wide produce
markets, it all tends to even out.

   Selenium in soils is basically in the soluable selenate form, which
is leachable by water.  It comes up in volcanic cinder cones,and when
it rains, it leaches out into water systems (occassionally reaching
toxic levels, as in Kesterton).  Land which was once at the bottom of
some old lake or ocean tends to be high selenium, therefore, as is
volcanic soil which is fairly new.  The rest (all other soils) are long
leached out.  Most large countries therefore have areas which are very
high in Se and others which are very low, simply because of the
leaching effect.  Example: once upon a time they had to ship feed from
South Dakota (high in Se) to Ohio (low in Se) to take care of the
selenium imbalance in those states.  But these days, as I said, the
shipping of produce is so mobile that it's not much of a problem any
more.

                                          Steve Harris, M.D.


From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: misc.health.alternative,sci.med.nutrition
Subject: Re: selenium(200mcg) info?
Date: 12 Jul 1998 04:45:27 GMT

In <6o9cev$egn$0@206.104.242.57> suequill <suequill@pan-tex.net>
writes:

>Also, can't find the connection for it now, but Dartmouth Hitchcock
>Medical Center  16 July 97  stated, that they have demonstrated a
>crucial role for selenium in the control of  thyroid hormone effects
>in the brain and fat tissue.


   The deiodinase which converts T4 to T3 is known to be a selenium
enzyme-- the second discovered after glutathione peroxidase, I believe.

   This might be a little more important for people with hypothyroidism
who are taking T4 replacement only.  So far, I haven't been able to
find any reports of clinical thyroid effects attributable to Se levels,
but who knows what future research will yield.  Often you don't find
what you don't look for, and the Se/thyroid connection hasn't been
known for less than a decade.

   As for which form of Se is best, note that most of the animal
anticancer studies have been with the inorganic salt.  The latest
positive human study used selenized yeast (selenomethione).  I suspect
it doesn't matter which you take.  But we don't know for sure about
that, either.  Suspenders and belt people will take both forms, perhaps
200 mcg of each.  That ought to pretty much take care of you, and still
stay way below tox range.  Tell you loved ones and friends to be on the
lookout for garlic sweat and garlic breath on you-- the very first sign
of slow and chronic Se overload.  If you don't specifically tell them,
they'll just think you eat pizza all the time.

                                    Steve Harris, M.D.


From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med.nutrition
Subject: Re: Selenium toxic?
Date: 14 Aug 1998 19:07:22 GMT

In <e440AH5x9GA.185@upnetnews05> "Jim" <jborkan@email.xmsn.com> writes:

>One critical aspect aside form the potency is the source of selenium. The
>inorganic salts, i.e. Sodium Selenate (or Sodium Selenite) or any other
>salt freely disassociates in the GI tract leaving free selenium, which
>has serious toxicity, although I do not believe there have been studies
>specifically on these forms to determine toxic levels.


    On the contrary, I resist the notion that selenium as the inorganic
salt is any more toxic than selenium as incorporated into amino acids.
They are interconvertable in the body, and the selenoamino acids in
muscle represent a long term storage pool.  Much as in the case with
vitamin A, you don't start seeing chronic selenium toxicity (the garlic
breath, etc) until that storage pool is overwhelmed (of course, VERY
high doses of selenium can cause toxic symptoms immediately).  Seems to
me that yeast would be just as effective at doing this (overloading
your stores) as any other form.  Indeed, I've seen balance studies
which indicate that the Se in selenomethione is better retained by the
body than the Se in SeO3= or SeO4=, so this form may be even MORE
liable to produce toxicity at a given chronic dose (ie, there may be
some equivalence ratio between organic and inorganic Se; I just don't
know what it is).

   One other thing to remember-- most of the animal experiments showing
the anticancer properties of selenium were done with the selenite salt.
It's just as good a form of selenium as any other.  If you're paying
good money for a yeast selenomethionine that's a lot more expensive per
mcg than selenite, you're probably wasting $.  On the other hand,
looking at the market, there are only a few selenite and selenate
preparations around (Twinlab, VRP), and they're just as expensive as
the selenomethione, which is produced in huge quantities by the
selenized yeast people, and is rapidly becoming the industry standard.
The howler being that your body probably has to break down
selenomethione all the way to inorganic Se to make selenocysteine <g>.

                                       Steve Harris, M.D.

From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med.nutrition
Subject: Re: Two selenium questions.
Date: Mon, 6 May 2002 22:48:05 -0600
Message-ID: <ab7mfk$n54$1@slb7.atl.mindspring.net>

"tintinet" <tintinet@altavista.com> wrote in message
news:7610a557.0205061440.659999e8@posting.google.com...
> Elmer Ogryzlo <ogryzlo@chem.ubc.ca> wrote in message
> news:<ogryzlo-30C45D.11484906052002@nntp.ucs.ubc.ca>...
> > In article <3CD4FEA8.8000804@virgin.net>,
> >  Ann R Quay <ann.r.quay@virgin.net> wrote:
> >
> > > What is it that makes a selenium supplement smell like stinky feet?
> > > If a person took this supplement would they come to smell like that as
> > > well?
> >
> >    The answer is yes, if you took much more than the recommended
> > supplement.  I had a student working with selenium (hydrogen selenide
> > actually) which not only is very smelly (like it's cousin hydrogen
> > sulphide) but the student found that it was absorbed by his clothing and
> > body (lungs?).  Not only did his family complain about the odors
> > emanating from his body and clothing, but he often remarked that he
> > noted on many occasions that there were more than a few empty seats
> > around him on the bus although the rest of the bus was crowded.
> >
> > Elmer
>
> That might almost be humorous if selenium weren't toxic in slightly
> higher than normal doses. I doubt supplementation of 200 mcg/day
> causes perceptibly increased b.o.

COMMENT

The toxicity is overrated-- in industry people have been loaded with so much
selenium that the allotrophic deposits under their fingernails turned them
red.  It's only when the nails start to fall OUT that you need to worry....

And yes, long before that, selenium will give you a rather garlicy body odor
and breath. Being an unusually good retainer of the stuff, I can begin to
smell selenium in my sweat at 400 ug a day, and I can taste it in the
mornings at only 200 ug a day. So 100 ug a day in a supplimentation is my
practical limit.

SBH






 






































































































































































































Index Home About Blog