Re: Vitamin E dangerous?

Hi Mark:

Quoted message said:

Consider the vit. e info at the linus pauling institute:

http://lpi.oregonstate.edu/infocenter/vitamins/vitaminE/index.html

A click on "sources" lists foods and content, and gets in part:

"Synthetic alpha-tocopherol, which is often found in food additives
and nutritional supplements, is usually labeled
all-rac-alpha-tocopherol or dl-alpha-tocopherol, meaning that all
eight isomers of alpha-tocopherol are present in the mixture. Because
half of the isomers of alpha-tocopherol present in
all-rac-alpha-tocopherol are not usable by the body, synthetic
alpha-tocopherol is less bioavailable and only half as potent."

The article on which so many news reports have been given is available
in full.
Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase
All-Cause Mortality
http://www.annals.org/cgi/reprint/0000605-200501040-00110v1

There are some links for response articles at the end.
The site is real slow right now so I can't tell if they are
accessible.

Frank

"Jefferson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi Mark:

Quoted message said:

Consider the vit. e info at the linus pauling institute:

http://lpi.oregonstate.edu/infocenter/vitamins/vitaminE/index.html

A click on "sources" lists foods and content, and gets in part:

"Synthetic alpha-tocopherol, which is often found in food additives
and nutritional supplements, is usually labeled
all-rac-alpha-tocopherol or dl-alpha-tocopherol, meaning that all
eight isomers of alpha-tocopherol are present in the mixture. Because
half of the isomers of alpha-tocopherol present in
all-rac-alpha-tocopherol are not usable by the body, syntheticbstr
alpha-tocopherol is less bioavailable and only half as potent."

The article on which so many news reports have been given is available
in full.
Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase
All-Cause Mortality
http://www.annals.org/cgi/reprint/0000605-200501040-00110v1

There are some links for response articles at the end.
The site is real slow right now so I can't tell if they are
accessible.

Yes they are. I downloaded the full articles available per the
link at the end of the paper about 12 hours ago.
I've not download the available abstracts yet.

Quoted message said:

Frank

Jefferson said:

The article on which so many news reports have been given is available
in full.
Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase
All-Cause Mortality
http://www.annals.org/cgi/reprint/0000605-200501040-00110v1

There are some links for response articles at the end. See

http://www.annals.org/cgi/eletters/0000605-200501040-00110v1

There is evidence that the alpha form displaces the gamma form of
tocopherol in the body.

A High Wire search for the terms Jiang+Q+Gamma-tocopherol resulted in 44
finds - http://tinyurl.com/48cu4. A similar search without Jiang+Q
results in 498 finds - http://tinyurl.com/3tkzk

"{gamma}-Tocopherol ({gamma}T), the major form of vitamin E in U.S.
diets, and its physiological metabolite 2, 7,
8-trimethyl-2-(ß-carboxyethyl)-6-hydroxychroman ({gamma}-CEHC), in
contrast to {alpha}-tocopherol ({alpha}T), the primary vitamin E in
supplements, inhibit cyclooxygenase-catalyzed synthesis of prostaglandin
E2 (PGE2) in activated macrophages and epithelial cells. ... These
findings provide strong evidence that {gamma}T shows anti-inflammatory
activities in vivo that may be important for human disease prevention
and therapy." Source: {gamma}-Tocopherol, but not {alpha}-tocopherol,
decreases proinflammatory eicosanoids and inflammation damage in rats
http://www.fasebj.org/cgi/content/abstract/17/8/816

"There is now a consensus that atherosclerosis represents a state of
heightened oxidative stress characterized by lipid and protein oxidation
in the vascular wall. The oxidative modification hypothesis of
atherosclerosis predicts that low-density lipoprotein (LDL) oxidation is
an early event in atherosclerosis and that oxidized LDL contributes to
atherogenesis." Source: Role of Oxidative Modifications in
Atherosclerosis -
http://physrev.physiology.org/cgi/content/abstract/84/4/1381

The early stages of atherosclerosis such as fatty streaks and complete
encirclements of arteries as evidenced by autopsies of people in their
late teens to early 20s suggests that lifestyle (diet and exercise) is
a problem in a high proportion of people way before the clinical effects
are realized in various degenerative diseases. Science is left wanting.

Frank

Jefferson <[email hidden]> wrote

Quoted message said:

"Synthetic alpha-tocopherol, which is often found in food additives
and nutritional supplements, is usually labeled
all-rac-alpha-tocopherol or dl-alpha-tocopherol, meaning that all
eight isomers of alpha-tocopherol are present in the mixture. Because
half of the isomers of alpha-tocopherol present in
all-rac-alpha-tocopherol are not usable by the body, synthetic
alpha-tocopherol is less bioavailable and only half as potent."

Something I don't understand here. WHY aren't all eight of the
stereoisomers bio-available? When a substance has to activate a
receptor, its stereo conformation is critically important. (assuming
the receptor is chrial, but that's true of all our proteins.) But an
antioxidant is just floating around in the plasma, waiting to bump
into a free radical. And most of the free radicals are very small,
non-chiral molecules. So I don't see why the optical conformation
should have a major effect on its activity. I realize that when
you've got more than one chiral carbon, some isomers will be more
stearicly hindered than others. But that shouldn't be enough to
completely lose the antioxidant activity, should it?

Or is it just that the Vitamin E has to get transported to where it's
needed and the transport mechanism is specific to a single
stereoisomer? Just guessing.

Meanwhile I'm realizing that I don't understand the
quenching/regeneration cycle for vitamin E or for other antioxidants.
E.g, I've seen the diagrams of alpha-tocopherol. But the 'business
end' of the molecule isn't labled - what part of the structure reacts
- and what's the product - when it runs into a superoxide molecule in
a dark alley? And afterwords, how does it get regenerated?
If somebody could point me to a web-based tutorial or FAQ - I'd be
much obliged. My googling didn't get me there. I mean, I found lots
of FAQs on antioxidants, but they didn't get down into the detailed
chemistry. Probably reflecting that the Questions I'm posing are not
at all Frequently Asked. :-)

Adam Becker

On 13 Nov 2004 21:55:37 -0800, [email hidden] (Adam Becker
Sr) wrote:

snip...>

Quoted message said:

Something I don't understand here. WHY aren't all eight of the
stereoisomers bio-available? snip....

Or is it just that the Vitamin E has to get transported to where it's
needed and the transport mechanism is specific to a single
stereoisomer? Just guessing.

I think you're onto it here. Here's a partial explanation:
http://www.jlr.org/cgi/content/full/39/8/1529

Quoted message said:

Meanwhile I'm realizing that I don't understand the
quenching/regeneration cycle for vitamin E or for other antioxidants.
E.g, I've seen the diagrams of alpha-tocopherol. But the 'business
end' of the molecule isn't labled - what part of the structure reacts
- and what's the product - when it runs into a superoxide molecule in
a dark alley? And afterwords, how does it get regenerated?
If somebody could point me to a web-based tutorial or FAQ - I'd be
much obliged. My googling didn't get me there. I mean, I found lots
of FAQs on antioxidants, but they didn't get down into the detailed
chemistry. Probably reflecting that the Questions I'm posing are not
at all Frequently Asked. :-)

LOL. Probably not. But if you find anything interesting, do share it.

George M. Carter

On Sat, 13 Nov 2004 12:37:40 -0500, Jefferson <[email hidden]>
posted:

Quoted message said:

The early stages of atherosclerosis such as fatty streaks and complete
encirclements of arteries as evidenced by autopsies of people in their
late teens to early 20s suggests that lifestyle (diet and exercise) is
a problem in a high proportion of people way before the clinical effects
are realized in various degenerative diseases. Science is left wanting.

So "what" discovered these early changes, if it wasn't "science"??

Dunne E. Dawe said:

On Sat, 13 Nov 2004 12:37:40 -0500, Jefferson <[email hidden]>
posted:

Quoted message said:

The early stages of atherosclerosis such as fatty streaks and complete
encirclements of arteries as evidenced by autopsies of people in their
late teens to early 20s suggests that lifestyle (diet and exercise) is
a problem in a high proportion of people way before the clinical effects
are realized in various degenerative diseases. Science is left wanting.

So "what" discovered these early changes, if it wasn't "science"??

The point is that there is still controversy in nutrition science and
the autopsies are an after the fact situation rather than a preventive.
Lack of nutrition knowledge is causing premature aging.

To be more emphatic on the issue, particularly for atherosclerosis, in
the report to the 72nd Scientific Sessions of the American Heart
Association the following was mentioned:

Dr. Nissen's group (Steven E. Nissen, MD, Cleveland, Ohio) evaluated 300
transplant donor hearts that were harvested from young people who had
died traumatically. These hearts were then analyzed with intravascular
ultrasound to assess the degree of atherosclerotic heart disease. The
results of this study showed coronary atherosclerotic disease in a large
number of young people: 17% of patients less than 20 years of age, 60%
of patients between 30 and 39 years of age, and 71% of patients between
ages 40 and 49 had coronary artery disease. Dr. Nissen concluded that
the patients who die of a plaque rupture when they are 45 years old
probably have had the disease since they were teenagers. He called these
results a 'wake-up call for America.'" (Source: 72nd Scientific Sessions
of the American Heart Association, November 8, 1999, "Evaluation by
Intravascular Ultrasound"😉.

The finding about plaque during the Korean conflict wasn't much
different than the above. Over 80% of men in their early 20s in which
autopies were performed had signs of plaque deposits in the coronary
arteries. So science was lagging some 45 plus years in finding a solution.

Frank