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MEGADOSES of vitamin C might lead to cancer, warn chemists.

Vitamin C helps mop up the destructive free radicals blamed for ageing. But
in large doses, it may have the opposite effect by breaking down natural fatty
acids in the body into potentially damaging compounds, researchers at the
University of Pennsylvania reported recently.

Now Peter Cragg, Karl Pavey and their colleagues at the University of
Brighton have set out to discover if these breakdown products really do harm
DNA. They bound strands of human DNA to a gold-coated quartz crystal and passed
a current through the crystal to make it vibrate. They also incubated vitamin C
with a fatty acid for 2 hours, and then passed the resulting mixture over the
crystal.

With high levels of vitamin C鈥攅quivalent to taking 2 grams per
day鈥攖he frequency at which the crystal vibrated dropped. This change
indicates that something had changed the mass of the DNA by binding to it, which
would cause problems when the DNA came to replicate. 鈥淵ou鈥檒l see a mistake in
the replication,鈥� says Cragg.

This means high doses of vitamin C may lead to cancer, the researchers warn.
鈥淭here are a lot of people taking very high doses,鈥� says Pavey. 鈥淚t鈥檚 easy to
walk into a health-food store and buy 1-gram tablets.鈥� In Britain, the
recommended daily dose is just 30 milligrams.

But the researchers have only tested free DNA. In the body, the harmful
molecules would have to cross into the cell nucleus. 鈥淎lthough the 2-gram dose
was very damaging, we don鈥檛 know how much of that would get to the DNA in the
cell,鈥� says Pavey.