There is no doubt that alcohol abuse is bad for the brain - but could there be health benefits for moderate drinkers?

Who are moderate drinkers?
They are people who drink alcohol every week, but not to excess.

Drinking "in moderation" is usually taken to mean consuming seven to 14 units of alcohol a week, equivalent to six pints of average-strength beer or seven glasses of wine.

The UK guidelines say that drinking no more than 14 units a week on a regular basis will keep health risks to a low level.

Light drinkers are those who drink fewer than that - between one and seven units.

So moderate drinking is OK?
The research is contradictory and so the answer isn't straightforward.

Some research suggests that drinking one or two units of alcohol a day - particularly red wine - could be of benefit to brain health, but other scientists are more sceptical.

A study published on Thursday in the British Medical Journal found that moderate drinkers were at lowest risk of dementia, compared to heavy drinkers and non-drinkers, but this may be because they tend to lead generally healthy lives and are less likely to smoke or eat unhealthily.

Another study found that, even in moderation, drinking alcohol could increase the risk of dementia.

How can alcohol damage the brain?
Drinking alcohol can cause your blood pressure and blood cholesterol to rise which, in turn, can damage the blood vessels supplying the brain, causing problems like vascular dementia.

It can also damage memory.

Continuous heavy drinkers, including binge drinkers and those who are dependent on alcohol, are most at risk from harming their brains in this way and developing dementia.

Recent research from France found that people who were dependent on alcohol or had a health issue caused by regular heavy drinking were three times more likely to develop dementia than other people.

Heavy drinkers are more likely to be smokers, have depression and lead unhealthy lives, which also increases the risk of dementia.

Another study of drinking habits in 19 countries found that regular excess drinking could shorten a person's life by between one and two years.

The same research warned that people who drank more than 18 alcoholic drinks a week could lose four to five years of their lives.

Is there any safe level, in that case?
The chief medical officer in England says that drinking any level of alcohol carries a health risk for anyone.

The more you drink on a regular basis the greater the risk of developing a range of health problems.

These include liver disease, cancer, heart attacks and stroke.

Current UK guidelines advise that men and women should drink no more than 14 units of alcohol a week.

Experts say keeping to this limit and cutting out heavy drinking episodes during the week, while keeping several days alcohol-free each week, lowers the risk of health problems - as well as accidents and injuries.