When the study conclusions have no basis in logic, that's when!
It is important to understand that this conclusion was pure speculation by Jane E Brody of the New York Times. According to scientists Brody didn't interview, e.g. Bruce Ames of University of Califonia, the DNA damage, if any, is quickly repaired by B-vitamin based enzymes, and most food, such as onions and alpha sprouts, have been shown by these same experiments to cause "DNA Damage".
This is simply more evidence of the ongoing campaign, disguised as news, to discredit vitamin C. There is no experimental proof or evidence of any connection between vitamin C intake and the diseases warned about in these news articles. In fact, direct evidence to the contrary exists that vitamin C prevents these diseases.
Following Contributed by
Richard M. Humphrey
Yahoo! News Local Headlines
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Thursday April 9 11:30 AM EDT
Too much Vitamin C can hazard health
NEW YORK, April 9 (UPI) _ Nobel laureate Linus Pauling used to tout
the benefits of massive doses of Vitamin C, but a British study says
taking more than 500 milligrams of the vitamin can be hazardous to the
genes.
Pauling, a chemist, used to take 12,000 milligrams a day.
But a report by chemical pathologists at the University of Leicester
in the current issue of Nature says instead of the antioxidant
benefits many expect from taking the vitamin supplement, they get the
opposite effect.
In a six-week study of 30 healthy men, the researchers found the
vitamin allowed free radicals to attack the adenine bases of DNA,
converting them to unhealthy levels of oxoadenine.
The research backs up laboratory studies done by Dr. Victor Herbert of
New York's Mount Sinai School of Medicine.
Herbert told the New York Times that vitamin C taken as supplements
converts harmless ferric iron to harmful ferrous iron, which attacks
the heart and other organs. Naturally occurring vitamin C has no such
harmful effect, he says.
The recommended daily intake of Vitamin C in the United States and
Britain is 60 milligrams a day, which can be obtained in foods, such
as six ounces of orange juice.
_-
Copyright 1998 by United Press International.
All rights reserved.
Reuters New Media
Yahoo! News Health Headlines
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Wednesday April 8 6:34 PM EDT
High Doses Of Vitamin C May Be Harmful
LONDON (Reuters) -- The benefits of taking high doses of vitamin C as
a daily dietary supplement are questionable, and the practice may even
be harmful, according to a team of British researchers.
Dr. Ian D. Podmore and colleagues from the University of Leicester,
UK, report that vitamin C may have a deleterious effect when taken in
daily doses of 500 milligrams (mg). Their findings follow a trial of
30 healthy volunteers who were given doses of 500 mg -- or about eight
times the UK recommended daily allowance -- for a period of 6 weeks.
In the April 9th issue of the journal Nature, the researchers report
that at a dose of 500 mg/day vitamin C has both a damaging pro-oxidant
as well as a beneficial antioxidant effect on two important markers of
molecular damage, 8-oxoguanine and 8-oxoadenine.
"This is the first time that anybody has ever looked at doses or at a
supplementation dose in vivo, in human subjects, where we've managed
to measure genetic damage using the markers as indicated, 8-oxoguanine
and 8-oxoadenine," co-researcher Dr. Joseph Lunec told Reuters in an
interview.
Lunec said that at 500 mg/day vitamin C has the potential of reducing
oxidative stress in humans, but superimposed upon this is the
pro-oxidant, deleterious effect.
"The bottom line is that the dose (500 mg) is not necessarily the
optimal dose to use as a supplement," he said.
In their paper, the researchers note that the body's antioxidant
defences resist oxygen radicals that have the potential of damaging
DNA. However, if the balance of defences is altered, this can result
in oxidative stress. This stress can give rise to biomolecular damage
that may play a role in diseases such as cancer.
"Because we know DNA damage is a sequeli of oxidative stress and these
are supposedly antioxidants, then theoretically vitamin C should
reduce the oxidative stress," Lunec said.
"But in fact we've shown that although it does have a capacity at 500
mg to reduce that oxidative stress in humans, there is a deleterious
effect superimposed upon that," he added.
Lunec said that the value of taking high doses of vitamin C
supplements has been questioned in the past because it has been shown
that "...as soon as you saturate your tissues you begin to excrete the
vitamin C." The current study suggests that high doses may be doing
damage as well.
"We shouldn't tell people to take as much vitamin C as they can to
supplement their food," he said. SOURCE: Nature (1998;392:559)