Alcohol consumption in excess has well-documented negative effects on both short- and long-term health, one of which is brain damage that can lead to Alzheimer's disease or other forms of dementia.

Can alcohol consumption increase dementia risk?

Excessive alcohol consumption over a lengthy time period can lead to brain damage, and may increase your risk of developing dementia. However, drinking alcohol in moderation has not been conclusively linked to an increased dementia risk, nor has it been shown to offer significant protection against developing dementia.

As such, people who do not currently drink alcohol should not be encouraged to start as a way to reduce dementia risk. Conversely, those who drink alcohol within the recommended guidelines are not advised to stop on the grounds of reducing the risk of dementia, although cutting back on alcohol consumption may bring other health benefits.

How can alcohol damage the brain?

Heavy alcohol consumption over a long period of time can lead to brain damage. People who drink heavily over a long period of time are more likely to have a reduced volume of the brain's white matter, which helps to transmit signals between different brain regions. This can lead to issues with the way the brain functions.

Long-term heavy alcohol consumption can also result in a lack of vitamin thiamine B1 and Korsakoff's Syndrome, a memory disorder affecting short term memory.

Is moderate alcohol consumption safe for the brain?

Some research has indicated that individuals who drank in moderation were less likely to develop Alzheimer's disease or any other form of dementia than those who consumed zero alcohol.

Some protective effects of alcohol have been seen on the brain, such as reduced thickness of blood (called plasma viscosity) and increased levels of healthy cholesterol (also known as HDL cholesterol) in the body. Both of these effects have been suggested to help lower the risk of developing dementia.

However, the evidence produced by studies that link moderate alcohol consumption with a lower likelihood of Alzheimer's disease does have some flaws. For example, many of these studies classified 'non-drinkers' as both people who have given up alcohol consumption due to health reasons (such as previous alcoholics) and lifetime non-drinkers.

What should I take away from this research?

The link between alcohol and dementia (or lack thereof) in non-drinkers however is not fully understood and individuals who do not currently drink alcohol should not start as a method of protection against the development of dementia.

From the evidence collected to date, it is not possible to determine what effect drinking within the NHS recommended alcohol guidelines has on a person's risk of dementia.