HEALTH / Second Opinion

AS WE age, brain cells die, never to be replaced: some estimates put the rate at 10,000 a day from a total of 100 billion. Standard medical teaching has been that heavy drinking of alcohol accelerates this natural loss of brain cells, but recent research from Denmark has added to the evidence that this view may need to be modified.

Without doubt, prolonged heavy drinking damages the brain: it shrinks it. Studies of living alcoholics and post mortem examinations of their brains have consistently shown that the internal, fluid spaces in the brain become larger, and that the actual volume of the cerebral cortex - the part that does the thinking - is reduced. The assumption has been that this loss of brain volume is due to the death of brain cells, but that view has now been challenged.

The Danish researchers collected brains from 55 alcoholics and counted brain cells in defined regions. The results were compared with those from brains of people who had no evidence of alcohol abuse. No differences were found, although the alcoholics did have smaller brains. Discussing their results in a recent Lancet article, the Danish researchers conclude that it is the white lining of the nerve pathways that is damaged by alcohol, not the nerve cell nuclei.

The important conclusion is that recovery is possible from alcohol-induced brain damage. Indeed, there is some evidence from other studies that when alcoholics give up drinking, brain shrinkage gradually reverses. Unfortunately, the majority of drinkers who reach this state drink until they are dead.

Whether it is nerve cells or white matter that gets damaged, the effect of alcohol on the brain is obvious, at least in heavy drinkers. Long before there are signs of dementia, they become slow thinkers, their conversation becomes repetitive and unresponsive to others, and their memories begin to fail.

Wide publicity has been given to the findings of studies showing that people who regularly drink small amounts of alcohol - one pint of beer a day or its equivalent in wine or spirits - have a lower rate of heart disease than total abstainers. Remarkably little research has been done on the effects of long continued moderate drinking on the brain, livers and stomach, all of which are damaged by heavy drinking (defined as four pints or more of beer a day, less for women.)

These are not just academic arguments. The amount people drink in a country such as Britain is determined largely by price, and that is determined by the Government. Is moderate drinking good for health, or at least neutral? If it is, as many doctors like to believe, then is it possible to have a nation of moderate drinkers without having a minority of alcoholics and problem drinkers? The disheartening figure is the proportion of people who drink to excess: most experts agree that around 10 per cent of the adult population drink half the total amount of alcohol in a country.

Most research on the effects of alcohol is done on the people who need medical treatment for the damage caused by their drinking. What is missing is research on the silent majority, who drink regularly but never become noisily drunk or argumentative. How much harm are they doing to their health?