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Discovery Shows New Vitamin C Health Benefits
Discovery Shows New Vitamin C Health Benefit
Source: Science Daily January 12, 2005
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.
Source: Science Daily January 12, 2005
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.