Red wine could help us live longer, scientists have claimed – reviving a furious debate over an ingredient once dubbed the ‘elixir of youth,’ the Daily Mail reports.

Resveratrol, which protects red grapes, cacao beans and Japanese knotweed against infections and drought, has divided experts for a decade over reports it could make humans live longer.

Now a study claims it could prolong our lives after all, because it imitates another protective enzyme – and just a ‘couple of glasses’ of red wine may be enough to benefit.

The study, published in the journal Nature, claimed it was time to finally ‘dispel much of the mystery and controversy about how resveratrol really works.’

Tests on mice previously showed resveratrol increased their lifespan and stamina and prevented diabetes, but critics complained it was being used in ‘unrealistically high doses.’

So the new study’s authors used a much weaker dose, up to 1,000 times smaller than before.

Their breakthrough then came when they combined resveratrol with an enzyme called TyrRS, which binds to the nucleus of a cell when it is under stress.

They found that when resveratrol and TyrRS were combined – as can happen naturally in the body – the pair imitating a cell-healing amino acid called tyrosine.

That process in turn activated a protein called PARP-1 which has a ‘DNA-repair factor thought to have a significance influence on lifespan’, the researchers said.