"COFFEE could protect from radioactivity"

["Franta, Jaroslav" <frantaj@aecl.ca>]

posted at
http://www.newscientist.com/cgi-bin/pageserver.cgi?/ns/19990626/newsstory3.h
tml

Four-minute warning 
Rob Edwards, New Scientist, 26 June 1999
DRINKING COFFEE could protect people from radioactivity, according to
scientists in India who have found that mice given caffeine survive
otherwise lethal doses of radiation.   A team from the Bhabha Atomic
Research Centre in Bombay injected 471 mice with varying amounts of caffeine
and then exposed them to 7.5 grays of gamma radiation--usually a lethal
dose. But 25 days later, 70 per cent of the mice given 80 milligrams of
caffeine per kilogram of body weight one hour before radiation exposure were
still alive. By contrast, all 196 of the mice not given caffeine and exposed
to the same dose of radiation had died.   Higher doses of caffeine--100
milligrams per kilogram--also led to the majority of the mice surviving over
the same period, as did administering the drug just half an hour before
irradiation. But all those given a lower dose of 50 milligrams per kilogram
died, along with mice that were only injected with caffeine after they had
been irradiated.   Kachadpillill C. George, who led the research, points to
earlier studies which suggest that caffeine--1,3,7-trimethylxanthine--reacts
with the hydroxyl radicals produced when cells are irradiated. This, he
says, could prevent the radicals from damaging cells and shutting down vital
bodily functions, such as the production of blood cells in bone marrow. Bone
marrow failure was the main cause of death among the irradiated mice.
George suggests that a better understanding of the protection offered by
caffeine might lead to improvements in the way that radiation is used to
treat cancer. His study is published in the latest Journal of Radiological
Protection (vol 19, p 171).   Other scientists are cautious about
interpreting George's results, however. Peter O'Neill, a radiation
researcher from the Medical Research Council's Radiation and Genome
Stability Unit at Harwell in Oxfordshire, agrees that caffeine reacts with
hydroxyl radicals. "But it may require very high concentrations in order to
protect cells from these radicals," he says.   A cup of fresh coffee
typically contains between 80 and 100 milligrams of caffeine while instant
coffee contains slightly less, according to Audrey Baker of the European
Coffee Science Information Centre in Oxfordshire. A person weighing 70
kilograms might therefore need to drink at least 100 cups to receive the
same dose as the mice. However, George believes that smaller amounts of
caffeine might protect people from lower doses of radiation than those used
in his experiment.   George is aware of the difficulty of extrapolating his
data from mice to humans. "But at the same time," he says, "it does suggest
that coffee might have some beneficial effects in protecting against
radiation."  	


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