A new study challenges long-held beliefs about alcohol and brain health, revealing a surprising finding – that there may be no safe amount to drink if you want to protect your mind from dementia.

Researchers have uncovered evidence that the comforting notion that light-to-moderate drinking can provide cognitive benefits may not be true. The research directly links alcohol consumption to an increased risk of developing dementia.

Projected estimates indicate that worldwide, the number of people living with dementia could balloon from more than 57 million in 2019 to nearly 153 million by 2050.

This trend points to an urgent need for effective prevention strategies, particularly as research continues to elucidate the complexities of known modifiable risk factors for the condition, one being alcohol consumption.

Research published earlier this month in eClinicalMedicine found that increased predicted alcohol consumption based on genetic factors is positively linked with a greater risk of developing dementia among current drinkers.

The findings cast doubt on the idea that any level of alcohol consumption is safe for dementia prevention.

While heavy drinking is a well-established risk factor for dementia, whether there is a similar association between light-to-moderate alcohol consumption and dementia has remained a subject of debate.

Past studies often contained biases, such as “abstainer bias”, where non-drinkers tend to be compared with drinkers who may enjoy better health or cognitive function, skewing the results.

These analyses sometimes didn’t account for cognitive decline occurring before the study or interactions with pre-existing health conditions.

Claire Sexton, Alzheimer’s Association senior director of scientific programs and outreach, told The Epoch Times that there remains some debate regarding the impact of light-to-moderate alcohol consumption.

“Some studies suggest that, among adults at midlife and older, light-to-moderate drinking may be associated with lower risk of cognitive decline compared with not drinking,” she said.

She added: Others show that moderate levels of alcohol may be associated with adverse brain outcomes, including lower hippocampal volumes.”

In this latest study, researchers examined data from the UK Biobank, screening nearly 314,000 white British adults who currently drink.

They looked for any direct relationship between light-to-moderate alcohol consumption and dementia risk using advanced genetic techniques, specifically Mendelian randomisation (MR), to lessen biases typical in observational studies.

Specifically, MR refers to the use of genetic variation to address whether modifiable factors cause different outcomes, such as disease.

Participants provided information about their drinking habits, with researchers tracking dementia cases through hospital and death records over 13.2 years. The average alcohol consumption recorded was 13.6 units per week, with nearly half of the participants exceeding the UK’s recommended limit of 14 units per week.

Men reported higher consumption than women, averaging 20.2 units weekly compared to women’s 9.5 units. Interestingly, a greater proportion of women (68.6 per cent) adhered to the recommended limits, compared to only 34.2 per cent of men.

The researchers observed a J-shaped pattern in their analysis, where low levels of drinking (11.9 units per week) were linked with the lowest dementia risk. However, this risk increased at higher consumption levels, especially among men, who showed the lowest dementia risk at 16.8 units of alcohol per week. 

While this J-shaped curve suggests a protective effect from moderate drinking, the study’s genetic analysis revealed a more nuanced reality.

The findings indicated that individuals possessing genes associated with greater alcohol consumption were more likely to develop dementia, particularly women.

According to researchers, this suggests that alcohol may have a direct role in elevating dementia risk, especially among people who consume higher amounts. In men, the risks of alcohol may be masked by other associated risk factors, including smoking.

The study concluded that a linear relationship exists between alcohol intake and the likelihood of developing dementia, which contradicts prior epidemiological findings suggesting that moderate alcohol intake conferred protective benefits.

The MR analysis indicated that these protective claims could stem from biases such as abstainer bias and confounding factors such as participants’ socio-economic status.

“This study reports that higher levels of current alcohol consumption were linked with increased incidence of dementia among current drinkers and found no ‘safe’ level of alcohol consumption,” Sexton noted. 

Although the researchers combined linear and non-linear MR analyses to strengthen their conclusions, they also acknowledged limitations. These include reliance on self-reported drinking habits and the demographic homogeneity of the UK Biobank participants, which potentially affected the findings’ applicability to broader populations.

The protective association between light-to-moderate alcohol consumption and dementia might be confounded by healthier lifestyle choices prevalent among moderate drinkers or the socio-economic factors influencing alcohol consumption patterns.

Drinking behaviours are related to many lifestyle factors, which couldn’t be controlled in most conventional epidemiology studies. These limitations highlighted the challenges of confounding and reverse causality in alcohol-related epidemiology studies.

Dr Asish Gulati, a board-certified neurologist in Washington, D.C., affiliated with George Washington University Hospital, told The Epoch Times in an email that alcohol can significantly impact brain health, “particularly in areas responsible for memory and cognition”.

She explained that two key components of alcohol, ethanol and acetaldehyde, are neurotoxic and can lead to inflammation and structural changes in the brain – especially in the hippocampus, which is essential for memory formation and spatial navigation.

[Neurotoxic substances are those that can harm the nervous system, potentially leading to psychiatric disorders or neurodegenerative diseases in humans].

“Research shows that the hippocampus is particularly vulnerable to alcohol, and even moderate consumption can lead to its shrinkage. Additionally, alcohol use can contribute to overall brain shrinkage and disrupt white matter integrity, which affects brain function,” Gulati wrote.

She explained that long-term drinking is associated with various cognitive impairments, including difficulties with learning, memory recall, and executive functioning.

“The negative effects of alcohol on brain health are profound,” she said, highlighting the importance of moderation and abstinence and awareness of its potential consequences

The hippocampus is part of the brain that is responsible for memory and learning. This small structure helps one remember, in the short term as well as in the long-term, and gain awareness from one’s environment. It is at risk of injury or damage from underlying conditions like Alzheimer’s disease.

Gulati warned that the brain’s ability to recover from alcohol-induced damage is limited, especially following long-term, heavy consumption.

She pointed out that damage to neurons and critical brain structures, particularly those involved in cognitive functions like memory, is often permanent.

She said that there is some neuroplasticity in the brain that allows for minor recovery in the early stages or with moderate alcohol intake but that chronic exposure can result in irreversible harm. However, ceasing alcohol consumption and adopting a healthy lifestyle can promote recovery.

Neurogenesis, or the formation of new neurons, can occur, particularly in the hippocampus, and this can lead to improvements in cognitive functions, said Gulati.

She added: “Though complete recovery may not be possible, significant benefits can arise from lifestyle changes and abstaining from alcohol.”

“The current study found a positive linear relationship between any level of alcohol consumption and dementia risk,” said Gulati.

She elaborated: “While the focus on current drinkers of white British descent may limit the generalisability of the findings, the results underscore the necessity for increased caution regarding any alcohol intake owing to its potential detrimental effects on cognitive health.”

• A dispatch originally published in The Epoch Times (Health). George Citroner reports on health and medicine, covering topics that include cancer, infectious diseases and neurodegenerative conditions.