Memory and thinking problems associated with binge drinking

Consuming eight or more alcoholic drinks per week puts drinkers at increased risk of brain injury associated with memory and thinking problems.

This is according to a new study published in Neurology, an American Academy of Neurology medical journal.

The study, conducted by researchers from the University of Sao Paulo’s Medical School in Brazil, does not prove heavy drinking causes brain injury, but shows an association.

The brain lesions are called hyaline arteriolosclerosis — a condition that causes the small blood vessels to narrow, becoming thick and stiff.

This makes it harder for blood to flow, which can damage the brain over time.

“Heavy alcohol consumption is a major global health concern linked to increased health problems and death,” said study author Alberto Fernando Oliveira Justo.

In South Africa binge-drinking at weekends and over the holidays, where more than one in five drinkers are classified as “heavy episodic” consumers of alcohol, has become a norm.

Prof Charles Parry, a specialist scientist at the South African Medical Research Council’s Mental Health, Alcohol, Substance Use and Tobacco Research Unit, said the use of alcohol was a big public health concern in South Africa.

“According to the 2024 World Health Organization’s Global Status Report on alcohol and health and treatment of substance use disorders, South Africans ranked fifth out of 47 countries in the African region in terms of the average daily intake of alcohol per drinker per day, at 27.2g of absolute alcohol,” said Parry.

The University of Sao Paulo study examined how alcohol affects the brain as people get older.

“Our research shows heavy alcohol consumption is damaging to the brain, which can lead to memory and thinking problems,” said Justo.

The study included 1,781 people who had an average age of 75 at death. All had brain autopsies.

Researchers examined brain tissue to look for signs of brain injury including tau tangles (build up of the protein associated with Alzheimer's) and hyaline arteriolosclerosis.

They also measured brain weight and the height of each participant. Family members answered questions about participants’ alcohol consumption.

Researchers then divided the participants into four groups: 965 people who never drank, 319 moderate drinkers who had seven or fewer drinks per week, 129 heavy drinkers who had eight or more drinks per week and 368 former heavy drinkers.

Researchers defined one drink as having 14g of alcohol, which is about 350ml of beer, 150ml of wine or 45ml of distilled spirits.

Of those who never drank, 40% had vascular brain lesions. Of the moderate drinkers, 45% had vascular brain lesions.

Of the heavy drinkers, 44% had vascular brain lesions. Of the former heavy drinkers, 50% had vascular brain lesions.

After adjusting for factors that could affect brain health such as age at death, smoking and physical activity, heavy drinkers had 133% higher odds of having vascular brain lesions compared to those who never drank, former heavy drinkers had 89% higher odds and moderate drinkers, 60%.

Researchers also found heavy and former heavy drinkers had higher odds of developing tau tangles, with 41% and 31% higher odds, respectively.

Former heavy drinking was associated with a lower brain mass ratio, a smaller proportion of brain mass compared to body mass and worse cognitive abilities. No link was found between moderate or heavy drinking and brain mass ratio or cognitive abilities.

In addition to brain injuries, impaired cognitive abilities were observed only in former drinkers.

Researchers also found that heavy drinkers died an average of 13 years earlier than those who never drank.

“We found heavy drinking is directly linked to signs of injury in the brain, and this can cause long-term effects on brain health, which may impact memory and thinking abilities.

“Understanding these effects is crucial for public health awareness and continuing to implement preventive measures to reduce heavy drinking,” said Justo.

When it comes to South Africa, Parry said when looking at the harm associated with drinking, an extremely important indicator is the extent of heavy episodic drinking .

This is defined as the proportion of drinkers who report consuming 60g of alcohol (five standard drinks) on a single occasion at least once in the past 30 days.

“Over one in five drinkers in South Africa (21.2%) are classified as being heavy continuous drinkers, comprising 28.0% of male drinkers and 9.2% of female drinkers. This refers to average consumption of at least 60g of AA a day in the past year.”

Parry said a number of measures were needed to curb high alcohol consumption, among them reforming the alcohol excise tax by applying it based on absolute alcohol content (AA), just over two standard drinks of 12g absolute alcohol every day.

Following government’s recent 6.75% sin tax increase on alcohol, consumer insights company Eighty20 looked at its impact using MAPS — which contains data from 20,000 face-to-face interviews — for insight.

According to Eighty20, apart from generating government revenue, the tax also aims to discourage the consumption of harmful substances and attempts to alleviates strain on the healthcare system caused by alcohol-related health issues and violence.

Sin tax generates significant revenue for the government-alcohol tax alone provided R41.5bn in 2022/23.

This contributes to South Africa's national budget, which includes total revenue of R2.1-trillion against total expenditure of about R2.5-trillion.

“Roughly, 43.6-million adults are contributing to VAT through their daily expenditure, withsin tax opening another source of revenue from the citizenry. About half of these adults drank alcohol in the past month,” said Eighty20.

“The Covid alcohol bans gave insight into the impact of alcohol on society. Quite often it is individuals who do not consume alcohol who carry the cost of these negative externalities, either through interpersonal violence or through a shared burden on the health system. 

“One study found that the alcohol bans reduced injury-induced mortality in the country by at least 14%, with the majority of this reduction occurring among men. It also found a significant drop in violent crimes including homicide, assaults and reported rape cases.”