|
 Scientists have discovered that
breakdown of alcohol by the body forms a substance that can
damage DNA dramatically and increase chances of cancer, with
people of Asian descent at a greater risk.
Researchers from the University of Minnesota found that
when human body breaks down, or metabolises, the alcohol in
beer, wine and hard liquor, one of the substances formed is
acetaldehyde, a substance with a chemical backbone that
resembles formaldehyde, a known human carcinogen.
Scientists also have known from laboratory experiments
that acetaldehyde can cause DNA damage, trigger chromosomal
abnormalities in cell cultures and act as an animal
carcinogen.
"We now have the first evidence from living human
volunteers that acetaldehyde formed after alcohol consumption
damages DNA dramatically," Silvia Balbo, who led the study,
said.
"Acetaldehyde attaches to DNA in humans - to the genetic
material that
makes up genes - in a way that results in the formation of a 'DNA adduct.'
It's acetaldehyde that latches
onto DNA and interferes with DNA activity in
a way linked to
an increased risk of cancer," Balbo added."Alcohol, a lifestyle carcinogen, is metabolised into
acetaldehyde in the mouth, and acetaldehyde is forming DNA
adducts, which are known major players in carcinogenesis," Balbo said in a statement.
Balbo pointed out that people have a highly effective
natural repair mechanism for correcting the damage from DNA
adducts. Most people thus are unlikely to develop cancer from
social drinking, although alcohol is associated with a risk of
other health problems and accidents.
In addition, most people have an enzyme called alcohol
dehydrogenase, which quickly converts acetaldehyde to acetate,
a relatively harmless substance.
However, about 30 per cent of people of Asian descent-
almost 1.6 billion people- have a variant of the alcohol
dehydrogenase gene and are unable to metabolise alcohol to
acetate.
That genetic variant results in an elevated risk of
esophageal cancer from alcohol drinking. Native Americans and
native Alaskans have a deficiency in the production of that
same enzyme.
To test the hypothesis that acetaldehyde causes DNA
adducts to form in humans, Balbo and colleagues gave 10
volunteers increasing doses of vodka (comparable to one, two
and three drinks) once a week for three weeks.
They found that levels of a key DNA adduct increased up to
100-fold in the subjects' oral cells within hours after each
dose, then declined about 24 hours later. Adduct levels in
blood cells also rose.
The study was presented at the 244th National Meeting &
Exposition of the American Chemical Society. |
