Three drinks every day enough to damage brain function

By MARTIN JOHNSTON and REUTERS

Knock back three cans of beer a day long-term and you are likely to develop the same kind of brain damage as alcoholics in hospital.

It will be less extensive, yet it could be enough to subtly impair day-to-day functioning, a US study has found.

Brain scans and memory tests revealed that men who quaffed more than 100 drinks a month and women who drank more than 80 suffered some problems.

Around 4 per cent of New Zealand drinkers consumed at this level of three or more drinks a day on average, Massey University alcohol expert Professor Sally Casswell said last night. A 2000 study showed that 87 per cent of New Zealanders aged between 15 and 65 drank.

Dr Dieter Meyerhoff and colleagues from the University of California at San Francisco examined 46 chronic heavy drinkers and 52 light drinkers.

The heavy drinkers - consuming an average of over 100 drinks a month for men and 80 for women - had been drinking at that level over three years before the study.

The researchers used imaging scans to look at the participants' brain structures, measured their levels of brain substances associated with healthy brain function and put them through standard psychological tests.

The heavy drinkers were significantly impaired on measures of working memory, processing speed, attention, executive function, and balance.

Measures of brain chemicals and structures showed similar damage to that seen in alcoholics in hospitals or treatment centres, although to a lesser extent.

Such changes could be too subtle to notice, but might still interfere with decision-making, emotional regulation, memory, motivation and muscle control.

"Socially functioning heavy drinkers often do not recognise that their level of drinking constitutes a problem that warrants treatment," the researchers wrote in the journal, Alcoholism: Clinical & Experimental Research.

Professor Casswell said the findings showed there was no such thing as a totally safe level of drinking.

Alcohol Advisory Council chief executive Mike MacAvoy said he agreed that heavy drinking damaged the brain slightly.

"The thing they don't talk about is that once people stop drinking the brain has a remarkable capacity to recoup some of its lost cognitive function, not necessarily 100 per cent, but it might be very close."