It is possible that we can grow biologically younger – and they key is in our blood, according to a scientist.

The biomedical gerontologist – an ageing expert – says that one day we won’t die from old age or ill health – only as a result of road accidents.

That is according to Briton Aubrey de Grey, who is chief science officer and co-founder of the SENS Research Foundation in Mountain View in California.

His company is one of an increasing number of Bay Area researchers pursuing the fountain of youth – focusing on isolating a factor in blood to turn back the hands of time.

The idea is that giving the plasma of the young to the old could help to reverse the effects of ageing.

And while it’s a concept that calls to mind vampire lore and stories of bathing in blood, research has suggested it’s not just pie in the sky.

Indeed, researchers at Stanford University, led by neuroscientist Tony Wyss-Coray, showed in a 2014 study that infusions of blood from young mice reversed cognitive and neurological impairments in old rodents.

Now biotech start-ups are racing to replicate this in humans, to achieve what we only know in science-fiction movies: eternal youth and health.

“The risk of death will remain the risk of death from causes other than aging — like being hit by a truck,” Dr de Grey told CBS SF Bay Area.

“We don’t know how soon we’re going to defeat aging. We should be able to keep people truly in a youthful state of health, no matter how long they live and that means the risk of death will not rise. Plasma transfusions are big hot property right now.”

A year after the Stanford research, biotech company Alkahest in San Carlo, California, experimented a step further in a series of trials injecting the blood plasma of 18-year-old humans into old mice.

They found that similar effects to the original study – human blood did rejuvenate both the body and brain, improving cognition and allowing them to frolic about like their younger counterparts.

Knowing that mice are biologically similar to humans, the researchers believed a similar technique could one day be used to benefit us.

Meanwhile, there may be science behind the fairytales of vampires feeding on the life blood of young maidens.

Blood plasma taken from young people and given to those with mild to moderate Alzheimer’s disease appears to help ward off its symptoms.

It has long been hoped that giving the blood of the young to the old could help to reverse the signs of ageing.

A study has now found so-called ‘vampire transfusions’ may help people with dementia regain the capacity to perform basic daily tasks, such as making their own meals, paying bills and remembering to take their medications.

This is what happened, according to researchers at Stanford University when they gave 18 people with Alzheimer’s disease the blood plasma of 18 to 30-year-olds.

Although this was an early-stage trial, set up only to determine if such transfusions were safe, the authors were surprised by the results.

The breakthrough follows a Stanford study in 2014 which found the blood of young mice rejuvenated the brain tissue of old mice and made them better able to learn.

At the time, the researchers said young blood may contain ingredients, as yet unknown, which are able to ‘recharge’ the brain.

The new findings were presented at the 10th annual Clinical Trial on Alzheimer’s Disease conference in Boston.