Five large glasses of wine a week is maximum before DNA starts to age

Excessive consumption of alcohol shrinks the caps on chromosomes, which can cause Alzheimer’s disease

THE answer to the age-old question of “How many drinks is really too many?” is anything more than five large glasses of wine, according to scientists from Oxford University.

Any more than this and the alcohol starts to take its toll on our DNA, affecting the caps on the end of our chromosomes called telomeres. Damage to these areas has been linked to Alzheimer’s and cardiovascular disease. People with healthier, longer telomeres are also thought to have longer lifespans.

Data from almost half a million people enrolled in the UK Biobank were used by the team to look for telltale genetic markers which show how much alcohol a person drinks. Their telomere length was measured in a laboratory after taking DNA from a swab.

The NHS recommends people do not drink more than 14 units a week and that this should be spread over at least three days to avoid binge-drinking.

The scientists found that a small amount of alcohol does not affect our DNA, but beyond the 17-unit threshold this changes and our telomeres come under attack. The top 40 per cent of drinkers, who consumed more than 17 units of alcohol a week, were found to have some telomere shrinkage caused by alcohol consumption. However, the remaining 60 per cent of people, who drink less than 17 units a week, were found to be genetically undamaged.

Someone who drinks 32 units a week, or about 10 large glasses of 13 per cent ABV wine, is biologically three years older than someone on 10 units a week (roughly three large glasses of wine), for example. But the research found no link between consumption and biological ageing below the 17-unit threshold, with someone having a one dram of whisky a week as unaffected as someone who has a glass of wine every weeknight.

“This finding suggests a ... minimum amount of alcohol consumption is required to damage telomeres,” the researchers write in their study, published in Molecular Psychiatry.

Exactly how alcohol intake is linked to telomere damage is unknown. One harmful mechanism suggested by the researchers is that the breakdown of alcohol molecules leads to oxidative stress and inflammation which are hazardous to DNA. The study’s lead author, Dr Anya Topiwala from Oxford Population Health, said: “Shortened telomeres have been proposed as risk factors which may cause ... severe age-related diseases such as Alzheimer’s disease.”