Many of us are living longer but not necessarily healthier. The problem is that ''people are outliving their brains'', says Richard Carmona, former surgeon-general of the US, in an interview with the Telegraph, London,

According to the Alzheimer’s Australia website, there are more than 332,000 Australians living with dementia and more than 1700 new cases identified in Australia each week.

We also know that changes in the brain begin to develop up to 20 or 30 years before dementia takes hold.

In his book 30 Days to a Better Brain, Dr Carmona wrote: ''We actually get by with substantial loss of brain function without realising that changes have occurred.''

The good news, however, is that ''just like the rest of your body, your brain can get better''.

Although the cause of Alzheimer’s is not fully understood, your genes play a ''role'' in its development. But so do your lifestyle choices.

In his book, Dr Carmona said a new field called epigenetics suggests ''it is possible to alter one’s genetic destiny by changing non-genetic factors such as lifestyle choices''.

And technically that’s right, said Elizabeth Coulson, associate professor at the Queensland Brain Institute.''“But it’s not as simple as suddenly drinking orange juice and turning the gene for getting Alzheimer’s off. With epigenetics there are things like smoking and possibly even exercise that do change the probability of whether different genes get turned on and off.''

A recent report titled Is the Incidence of Dementia Declining? also proposed that healthier lifestyles could reduce the risk of dementia.

While there are no guarantees, diet and exercise are good for everyone at every age, said Colin Masters, executive director at the Mental Health Research Institute at the University of Melbourne.

But not everyone will go on to get Alzheimer’s or dementia.

''There are some people whose brains are perfectly intact even though they live to 100 or 120, so it's the rest of their bodies that disintegrate,'' Professor Masters said.

''We don't quite know how yet to identify the completely intact brains, but the incidence of Alzheimer's disease, for example, possibly decreases after the age of 90,'' he said.

Despite this, many of us don’t know how to take care of our brain.

Taking care of our brain

Your Brain Matters is the first dementia risk reduction program in the world. Provided by Alzheimer’s Australia, the website offers five steps to brain health.

''While we are living longer, we’ve come to expect that we can also live younger,'' Dr Carmona said.

''We need to have strong, agile minds that can keep up with and help maintain our strong bodies.''

Alzheimer's Australia offers support, information, education and counselling. Contact the National Dementia Helpline on 1800 100 500.

SMH