However a simple online alcohol intervention program might be all it takes to change people's health outcomes, scientists from the University of NSW say.

Studies have shown drinking is the single most dangerous modifiable risk factor for dementia, in comparison to things like smoking, obesity, high blood pressure and diabetes, professors at the Centre of Healthy Brain Ageing say.

Even low levels of alcohol use - up to seven standard units a week - are associated with small but significant changes in the brains of older adults.

Nearly half a million Australians are diagnosed with dementia - which is the country's second leading cause of death - and that number is expected to more than double by the middle of the century.

But it's never too late to slow cognitive decline, researchers say.

"People who consume alcohol regularly have a genuine chance of preventing dementia if proper action is taken," explains Dr Louise Mewton, Scientia Fellow and lead investigator of the Rethink My Drink study.

Excessive alcohol consumption is an under-recognised problem among the baby boomer generation, the centre's co-chairs, professors Perminder Sachdev and Henry Brodaty, said.

One in five Aussies over the age of 60 are said to exceed official guidelines, enjoying more than two drinks a day - a greater percentage than any other age group.

"Its harm is not fully appreciated," the professors said in a joint statement. "This study is a great first step in demonstrating that something can be done about it."

Participants in the Rethink My Drink research will be asked to complete assessments over a year that will focus on alcohol use, memory and quality of life, with a view to helping them reduce consumption.

The program was deliberately launched before Christmas when people are more inclined to binge drink, Dr Mewton said.

"Before the festive season begins is the perfect time to arm yourself with the tools you need to start a healthy relationship with alcohol," she said.

Australian Associated Press