A drug that keeps one young forever?

London: A ‘fountain of youth' drug which could help people stay fit and healthy long into old age has been unveiled by doctors.

In tests, tiny amounts of the drug lenalidomide massively boosted immune system chemicals key to fighting off invaders from bugs to tumours. Concentrations of one of the protective compounds rose more than 100-fold.

Bolstering the body's defences could also make vaccines such as the flu jab more effective in those whose immunity has weakened with age, reports the Daily Mail.

An elixir of youth has long been a lasting theme of science fiction. In the 1985 film "Cocoon", starring Hume Cronyn and Jack Gilford, a group of elderly people are rejuvenated by aliens after swimming in their secret ‘lifeforce'.

Edward Goetzl of the University of California who has hailed the drug as a ‘fountain of youth pill', said: "We are definitely aiming for longer, healthy lifespan and a shorter period of frailty."

Goetzl began by studying levels of immune system chemicals called cytokines in a group of elderly adults, according to a California statement.

He found that amounts in healthy pensioners mirrored those of much younger people. But in frail pensioners vulnerable to infection, levels were low. Further work showed that lenalidomide could raise their levels in a way that no other pill or potion could.