By Yasmin Noone

Alzheimer’s disease prevention strategies are "double-edged swords" which, if adhered to strictly over a number of years, can either prevent the manifestation of the disease or do little to avoid the inevitable, an expert said. 

Professor Yaakov Stern from Columbia University's (USA) Taub Institute for the Research on Alzheimer's Disease and the Ageing Brain, has delivered a positive message about society’s ability to potentially beat the disease but still warns people that to-date, there is no ‘one-size fits all’ proven intervention recipe for the prevention of Alzheimer’s disease.

According to Prof Stern, this is because every brain is unique and what works to delay the onset of dementia in one person might not yield the same impact in another.  

Explaining why at the Australian Psychological Society symposium, Optimising Healthy Brain Ageing Symposium, held in Sydney yesterday, Prof Stern referred to the concept of ‘cognitive reserve’: where two people, with completely different lifestyles and dietary habits, have the same amount of Alzheimer’s changes occur in their brain yet one person is extremely affected by the disease and the other exhibits no or little manifestation.

He added that people with reserve cognitive capacity do lose brain cells as a result of the disease but because they have a sufficient reserve of cells, they do not fall within the effected range where dementia sets in.

Prevention strategies – like pumping weights, doing Tai Chi, adopting a healthy diet, drinking green tea, or even playing brain-training games – can help protect the brain reserve but the extent to which it will delay the onset of Alzheimer’s will vary person-to-person.

“Studies suggest there a whole load of exposures across the lifespan to do with increased reserve,” said Prof Stern.

“All of these things appear to be a protection.

“Yet the question here is really about interventions: How do we take this concept [of cognitive reserve] and make people age more successfully?

“The evidence suggests that it is good to remain active, exercise and be socially engaged. But, [it’s hard to say, from the evidence], how much cognitive engagement you should have. For example, should you do a course for a week or learn to fence?

“There is a lot of research going on right now to see what kind of interventions can improve ageing…But there is no definite rule of thumb that can give people [specific direction on interventions] as the research isn’t there yet.”

For example, he said, although studies suggest that exercise can potentially prevent or delay the onset of the disease, “we can’t say that if you exercise 20 minutes a day, you won’t get Alzheimer’s disease”.

“Some people who do everything right won’t get the disease. For others, [doing exercise and living a healthy life will] just mean that they might get it later than they would have otherwise.”

Prof Stern wants the public to be educated about the types of strategies they can adopt to reduce their risk of developing the disease however they should be aware that such preventative techniques “won’t stop the disease but [could potentially] put it off”.

“It’s a positive message but it comes with a note of caution. We don’t want people to feel like we have solved Alzheimer’s…[And], we don’t want to over-promise or say things that have not yet been supported by research.”

But, he concluded, Alzheimer’s research is currently at a “hopeful” stage and at some point soon, scientists will have more conclusive evidence about prevention interventions.

“We understand now that brain is more plastic than we have ever appreciated, even as we age.

“There are a lot of studies going on and we will sort of chip away at the problem…We also know the sorts of activities we can do to help [delay the onset of Alzheimer’s].”

Prof Stern’s advice to people wanting to possibly prevent the early onset and reduce their risk of developing the disease is to therefore life the best life they can.

“I think that people should do what they like to do. The trick is to remain engaged and engage in activities that you like.

“If you like to garden, garden. You don’t have to play chess. Just remain active and engaged. It’s when you close in and stop doing things that is really the issue.”