The mechanism behind the recent claim about red meat and colon cancer.
From: montygram (nazztrader_at_lycos.com)
Date: 01/14/05
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Date: 13 Jan 2005 17:22:24 -0800
Bruce Fife (and others), outside "mainstream" biomedicine,
understood the mechanism behind the recent study which the media has
been trumpeting lately (concerning the connection between red meat and
colon cancer) more than five years ago. Here is a germane passage from
his 1999 book, Saturated fat may save your life (page 153):
When meat is cut or ground, it not only increases its exposure to
oxygen, but iron is also released from the cells. This iron attacks
the fat within the meat, greatly accelerating oxidation. Ground meat
would be affected most because kore tissues are boken and exposed. The
older the meat, the more time is allowed for lipid peroxidation to
occur... The degree of oxidation will also vary with fat content. The
more polyunsaturated fat in the meat, the more peroxidation will occur.
Saturated fat is resistant to oxidation, so meat with a higher
saturated fat content will be safer to eat. Unfortunately, most
animals nowadays are given feed high in polyunsaturated fats ans so
their tissues also contain more of this fat. So the meat we eat has
undergone more lipid peroxidation than that eaten by our grandparents.
And then there's this report from www.sciencedaily.com that also
makes the connection between the kinds of fat you eat and the damage in
the body (as well as the role of antioxidant substances), though the
journalist (as usual) fails to mention that saturated fatty acids do
not go rancid in your body and do not cause damage. They raise serum
cholesterol levels slightly (in general) which is fine if you stay away
from the unsaturated fatty acids (except in trace amounts) and cook
food with a high lipid content correctly (boiled is best, and do not
consume homogenized dairy).
1/12/2005
Discovery Shows New Vitamin C Health Benefits
CORVALLIS - Researchers in the Linus Pauling Institute at Oregon State
University have made a major discovery about the way vitamin C
functions in the human body - a breakthrough that may help explain its
possible value in preventing cancer and heart disease.
The study, which explores the role of vitamin C in dealing with the
toxins that result from fat metabolism, was just published in a
professional journal, Proceedings of the National Academy of Sciences.
It contradicts the conclusions of some research that was widely
publicized three years ago, which had suggested that this essential
nutrient might actually have toxic effects.
The new OSU study confirmed some of the results of that earlier
laboratory study, which had found vitamin C to be involved in the
formation of compounds potentially damaging to DNA. But that research,
scientists say, only provided part of the story about what actually
happens in the human body.
The newest findings explain for the first time how vitamin C can react
with and neutralize the toxic byproducts of human fat metabolism.
"This is a previously unrecognized function for vitamin C in the human
body," said Fred Stevens, an assistant professor in the Linus Pauling
Institute. "We knew that vitamin C is an antioxidant that can help
neutralize free radicals. But the new discovery indicates it has a
complex protective role against toxic compounds formed from oxidized
lipids, preventing the genetic damage or inflammation they can cause."
Some earlier studies done in another laboratory had exposed oxidized
lipids - which essentially are rancid fats - to vitamin C, and found
some reaction products that can cause DNA damage. These test tube
studies suggested that vitamin C could actually form "genotoxins" that
damage genes and DNA, the types of biological mutations that can
precede cancer.
But that study, while valid, does not tell the whole story, the OSU
researchers say.
"It's true that vitamin C does react with oxidized lipids to form
potential genotoxins," said Balz Frei, professor and director of the
Linus Pauling Institute, and co-author on this study. "But the process
does not stop there. We found in human studies that the remaining
vitamin C in the body continues to react with these toxins to form
conjugates - different types of molecules with a covalent bond - that
appear to be harmless."
In human tests, the OSU scientists found in blood plasma
extraordinarily high levels of these conjugates, which show this
protective effect of vitamin C against toxic lipids.
"Prior to this, we never knew what indicators to look for that would
demonstrate the protective role of vitamin C against oxidized lipids,"
Stevens said. "Now that we see them, it becomes very clear how vitamin
C can provide a protective role against these oxidized lipids and the
toxins derived from them. And this isn't just test tube chemistry, this
is the way our bodies work.
"This discovery of a new class of lipid metabolites could be very
important in our understanding of this vitamin and the metabolic role
it plays," Stevens said. "This appears to be a major pathway by which
the body can get rid of the toxic byproducts of fat metabolism, and it
clearly could relate to cancer prevention."
Oxidation of lipids has been the focus of considerable research in
recent years, the scientists say, not just for the role it may play in
cancer but also in other chronic diseases such as heart disease,
Alzheimer's disease, and autoimmune disorders.
The toxic products produced by fat oxidation may not only be relevant
to genetic damage and cancer, researchers believe, but are also very
reactive compounds that damage proteins. For instance, there's a
protein in LDL, the "bad" cholesterol in your blood, which if damaged
by toxic lipids can increase the chance of atherosclerotic lesions. In
continuing research, the OSU team plans to study the role of this newly
understood reaction between vitamin C and toxic lipids in
atherosclerosis. In clinical studies they plan to examine the blood
chemistry of patients who have been diagnosed with coronary artery
disease, compared to a healthy control group.
"In the early stages of atherosclerosis, it appears that some of these
toxic lipids make white blood cells stick to the arterial wall, and
start an inflammatory process that ultimately can lead to heart disease
or stroke," Frei said. "When we better understand that process and the
role that micronutrients such as vitamin C play in it, there may be
strategies we can suggest to prevent this from happening."
The new findings, the OSU scientists say, also point to new biomarkers
that can be useful in identifying oxidative stress in the human body.
They may provide an indicator of people who may be at special risk of
chronic disease.
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