Source: The Times (UK)
Contact: letters@thetimes.co.uk

Alcoholics who dry out risk brain damage

BY NIGEL HAWKES, SCIENCE EDITOR

ALCOHOLICS who are "drying out" produce high levels of
chemicals that can kill brain cells, a study of men in Salvation
Army hostels has shown.

The chemicals, called kyurenines, peak on the fourth day of
detoxification. The peak coincides with a loss of memory,
suggesting that it is the production of excessive amounts of
kyurenines that causes characteristic memory loss among
longterm alcoholics.

Adrian Bonner, who produced the research with his
colleague Colin Martin of the Addictive Behaviour Centre at
Roehampton Institute, London, said: "The more often a
person has dried out and then relapsed, the more likely is it
that he has brain damage. We believe that a lot of this
damage might be avoided if kyurenine production could be
controlled by diet or by drugs during drying out."

The two researchers collaborated with the Salvation Army in
the research, which involved taking blood and urine samples
and conducting tests of brain function in 150 alcoholics in the
Army's hostels. They measured the levels of kyurenines for
several weeks and compared them with tests of brain
function.

Kyurenines are related to the mood chemical serotonin, both
of which are produced by the breakdown of tryptophan, an
amino acid that is found in food.

Only a small proportion of the tryptophan goes to produce
serotonin. The bulk is broken down in the liver to form
kyurenines and a related chemical, quinolinic acid.

Dr Bonner suspects that in alcoholics, the biochemistry is
altered so that more dietary tryptophan is diverted to the
liver, producing excessive levels of kyurenines and low levels
of serotonin. Without exception, the alcoholics they studied
were clinically depressed, indicating low serotonin levels.

Kyurenines are known to be linked to seizures ¡ often
experienced by alcoholics drying out ¡ while quinolinic acid
alters the functioning of brain proteins important in memory.

The elevated levels found during drying out could kill brain
cells in the hippocampus, so that repeated periods of
intoxication followed by drying out would bring about brain
degeneration. "The important thing is that we know the
process can be controlled by diet," Dr Bonner said.

"By altering the carbohydrates and proteins in the diet, or by
using drugs to target the enzymes in the liver that break down
tryptophan, we might be able to reduce the brain damage.
That could have enormous implicatons for the treatment and
rehabilitation of alcoholics."

First results of the study were presented last month at a
conference in Sweden. Now the researchers plan to extend
the study internationally, again with the help of the Salvation
Army.

Copyright 1997 The Times Newspapers Limited.