New research published in the British Medical Journal has found that moderate alcohol consumption may have protective effects against dementia. This claim is controversial as years of conflicting evidence have come before it. There’s no doubt that alcohol has a bad reputation when it comes to health, but it is becoming increasingly clear that the story may be much more complicated.
Dementia is described as a collection of symptoms related to the decline of cognitive function, including memory impairment, confusion and abnormal behaviour. It affects around 50 million people globally, with 10 million new cases being diagnosed annually. It is estimated that there will be as a many as 82 million people affected by 2030. As with many neurological disorders, isolating a clear cause is near impossible. Finding lifestyle factors that affect the onset of dementia can, therefore, help to delay its impact.
As with many neurological disorders, isolating a clear cause is near impossible
This new study is a 23-year follow-up of the Whitehall II cohort study, involving 10,308 adults recruited between 1985 and 1988. It found that those who consumed moderate amounts of alcohol (defined as 7-14 units per week) were at lower risk of developing dementia in later adult life than those who abstained from drinking altogether. The decrease is thought to be mainly due to a reduction in the number of cases of vascular dementia, the second most common cause of dementia after Alzheimer’s disease.
In spite of these results, it is important to recognise the many limitations of the study. As in most lifestyle-related research, there are many confounding variables which cannot be controlled such as diet and stress levels, which may affect the onset of dementia. Because of this, there are many studies which contradict the idea that moderate alcohol consumption is beneficial.
Those who consumed moderate amounts of alcohol (defined as 7-14 units per week) were at lower risk of developing dementia in later adult life than those who abstained from drinking altogether
The study finds that an increase of just seven units above the 14-unit boundary can increase the probability of dementia by 17%. However, in many countries, the recommended consumption of alcohol is much higher than 14 units, such as in Ireland where the recommended weekly limit is 21 units. It is clear that more research must be done to standardise the recommendations in order to protect people from the detrimental effects of binge drinking.
The study also finds evidence that drinking a large amount of alcohol has the opposite effect on the development of dementia. High levels of alcohol consumption increase blood pressure and cholesterol levels, putting more strain on the blood vessels in the brain, leading to the development of vascular dementia.
In many countries, the recommended consumption of alcohol is much higher than 14 units, such as in Ireland where the recommended weekly limit is 21 units
As with any incurable condition, lifestyle recommendations are likely to remain important in controlling the onset of dementia. However, when it comes to alcohol, recommendations are still contradictory and confusing. In spite of this, this research adds to the growing collection of evidence that suggests that, at least in some ways, alcohol may have a more complex impact on health than we think.