Here are the two reports. It does seem that the references were reversed.
Will correct this in the next printing. Sally Fallon
#1
Page 20: "The second study, published in Cancer Research, Septmenber 1999,
showed that high-dose vitamin C supplementation can accelerate the progession
of atherosclerosis by increasing the rate of intimal thickening."
Who are the authors of this study and what is the title?
#2
Page 21: "The final and perhaps most daunting report was the Los Angeles
Atherosclerosis Study, published in 2000 (?Where), which concluded that
500 mg vitamin C ingested daily is genotoxic, which means that synthetic
vitamin C can interfere with DNA and potentiate the growth of malignant
tumors"?
_Cancer Res._ (javascript:AL_get(this, 'jour', 'Cancer Res.');) 1999 Sep
15;59(18):4555-8. _Related Articles,_
(
http://www.ncbi.nlm.nih.gov/entrez/quer ... d=10493506) _Links_
(javascript:PopUpMenu2_Set(Menu10493506);)
(
http://www.ncbi.nlm.nih.gov/entrez/util ... long&pmid=10493506)
Stromal cell oxidation: a mechanism by which tumors obtain vitamin C.
_Agus DB_
(
http://www.ncbi.nlm.nih.gov/entrez/quer ... ract&term="Agus+DB"[Author]) , _Vera JC_
(
http://www.ncbi.nlm.nih.gov/entrez/quer ... ract&term="
Vera+JC"[Author]) , _Golde DW_
(
http://www.ncbi.nlm.nih.gov/entrez/quer ... ract&term="Golde+DW"[Author]) .
Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York,
New York 10021, USA.
d-agus@ski.mskcc.orgHuman tumors may contain high concentrations of ascorbic acid, but little is
known about how they acquire the vitamin. Certain specialized cells can
transport ascorbic acid directly through a sodium ascorbate cotransporter, but in
most cells, vitamin C enters through the facilitative glucose transporters
(GLUTs) in the form of dehydroascorbic acid, which is then reduced
intracellularly and retained as ascorbic acid. Mice with established hematopoietic and
epithelial cell xenografts were studied for the accumulation of injected
ascorbic acid and dehydroascorbic acid. Most hematopoietic and epithelial tumor
cell lines can only transport vitamin C in the oxidized form (dehydroascorbic
acid) in vitro; however, when grown as xenografts in mice, they rapidly
accumulated vitamin C after administration of radiolabeled ascorbic acid. The
involvement of the GLUTs in vitamin C uptake by the xenografted tumors was
demonstrated by competitive inhibition with D-glucose but not L-glucose. Because the
malignant cells were not capable of directly transporting ascorbic acid, we
reasoned that the ascorbic acid was oxidized to dehydroascorbic acid in the
tumor microenvironment. Tumor accumulation of vitamin C in animals injected
with ascorbic acid was inhibited by coadministration of superoxide dismutase,
implying a role for superoxide anion in the oxidation of ascorbic acid.
Whereas the epithelial cancer cell lines could not generate superoxide anion in
culture, the minced xenograft tumors did. Our studies show the transport of
dehydroascorbic acid by GLUTs is a means by which tumors acquire vitamin C and
indicate the oxidation of ascorbic acid by superoxide anion produced by cells
in the tumor stroma as a mechanism for generating the transportable form of
the vitamin.
PMID: 10493506 [PubMed - indexed for MEDLINE]
Vitamin C: friend or foe?
_Better Nutrition_ (
http://www.findarticles.com/p/articles/mi_m0FKA) ,
_June, 2000_ (
http://www.findarticles.com/p/articles/mi_m0FKA/is_6_62) by
_Patricia Andersen-Parrado_
(
http://www.findarticles.com/p/search?tb=art&qt="Patricia+Andersen-Parrado")
The story behind the headline
Vitamin C is one of those supplements that has always been synonymous with
safe. It's right up there with multi-vitamins in terms of what even
conventional medical doctors routinely advise their patients to take as a kind of
"insurance policy."
So, the recent news that vitamin C supplementation may increase one's risk of
developing atherosclerosis certainly came as a surprise.
This finding was presented at the American Heart Association's 40th Annual
Conference on Cardiovascular Disease Epidemiology and Prevention.
While interesting, it is important to note that this paper has not yet been
published in a peer-reviewed medical journal. And, there are prominent
nutrition experts who cast doubt on the findings.
In this study, the researchers measured the thickness of the wall of a neck
artery on 573 healthy men aged 40 to 60 over an 18-month-period. They found
that the men who took 500 mg of vitamin C daily had an increase in arterial
wall thickness that was 2.5 times greater than men who did not use supplements.