Living longer is all in the genes

Advances in genetic science could see future generations not only live longer but stay healthy and enjoy a better quality of life. Photo / Thinkstock

In Justin Timberlake's latest Hollywood blockbuster In Time, people can live for hundreds of years.

The gene that controls ageing has been switched off so everyone stops getting older at 25.

But there's a catch - once you hit 25 you have to start buying time to stay alive.

The rich live forever while the poor die young.

Away from the big screen, the idea of being able to put more than 100 candles on your birthday cake is one that would thrill many people.

But even if the dream becomes reality the big question is what would you do with all that extra time?

What sort of life would you have? Would you find a new career, spend time running around with your grandchildren, or languish in a nursing home?

Everything is possible, say scientists working on ways to help people not only live longer but stay healthy and enjoy a better quality of life.

Renowned Australian geneticist David Sinclair, who is based at Harvard Medical School in the United States, has spent years researching ways to develop medicines to keep people free of diseases well into old age.

He envisages a day when you can pop a pill for diabetes and also be protected against heart disease.

"I can imagine a future where 90-year-olds play tennis with their great grandchildren," he said.

"We are not talking about an extra 100 years or anything, but I think gradually we will learn how to make people get through their 50s, 60s and 70s without any disability or disease.

"It's not just about keeping people around for longer, it's about keeping them healthier in their middle years.

"The difference though is these medicines don't just work on one disease. We expect they may be prescribed for one disease but they will protect against 15 others."

But if people can stay physically fit thanks to these future drugs, what about their brains?

Over the next four decades the number of Australians developing the degenerative brain condition dementia is expected to quadruple.

Even if people with dementia are physically healthy, the memory loss, confusion and personality changes associated with dementia can have a major impact on their lives.

Baroness Susan Greenfield, an Oxford University professor who specialises in the physiology of the brain, says it is vital to keep people's brains healthy if they will be living longer.

The key to that, she says, is discovering what is special about the particular brain cells that are vulnerable to being destroyed by neurodegenerative conditions.

If scientists can do that, the door would be open to developing drugs to prevent the damaged cells from dying.

"People would be able to take a medication before the symptoms come on," Prof Greenfield said. "That's the dream."

Just like in Timberlake's movie, our genes hold the key to our longevity, scientists believe.

Professor Sinclair has focused his work on sirtuins, a class of gene which controls the ageing process and conditions associated with old age such as neurodegeneration.

He has shown in laboratory tests that when mice are given more sirtuins they live up to 25 per cent longer and are protected from heart disease, Alzheimer's and even cancer.

The 42-year-old geneticist has been working on developing synthetic molecules that "switch on" sirtuins in the body in the hope one day they will form the basis of drugs to protect people from the effects of ageing.

The molecules are 1000 times more powerful than the much-touted "fountain of youth" resveratrol, a sirtuin-boosting plant compound found in red wine.

Fans of resveratrol believe if it is taken at relatively young ages the powerful antioxidant found in blueberries, grapes and peanuts can help reverse diseases such as diabetes and cancer in old age.

"A main effect of these molecules, including resveratrol, is to boost up the energy [producers] of the body, the mitochondria," Professor Sinclair said.

"The mice we treat (with the synthetic molecules) have much more mitochondria and energy in their cells and they can run twice as far on a treadmill."

So if you can be in relatively good health with loads of energy heading towards your 100th birthday and beyond, what will you do with your time?

Keep working, says Professor Greenfield, who last week joined Professor Sinclair to deliver the University of NSW's 2011 Medicine Dean's Lecture on the possibility of happy and healthy ageing.

Prof Greenfield has come up with what she calls The Second Fifty Years Scheme, which would team up older workers with young graduates to help them set up businesses.

Instead of retiring in their 60s, people could choose to receive seed funding from the government to set up a business with a graduate who had all the latest skills in a particular field but not the experience of the older worker.

Prof Greenfield believes it makes perfect sense.

"Instead of saying everyone should go to university and everyone should retire, you could match people up and let there be a cross-generational enterprise," she said.

"You wouldn't be forced to do this. But wouldn't it be more interesting and fulfilling for you than being patronisingly given Sudoku to play with or pensioned off on the golf course?"

But Professor Greenfield says for such a scheme to succeed society's attitude towards the elderly must change.

"It should be something you are working towards and celebrate rather than something you dread and fear," she said.

"Just look at people like Desmond Tutu or the Queen or Warren Buffett. These are people in their 80s who are still being very lively and constructive and they are doing things that help the world.

"There's no reason why you automatically have to decline."

- AAP