Over the last decade, it has become clear that just as changes in diet and exercise will improve physical fitness, the 'ageing' brain also benefits from simple changes in environment and lifestyle.
And as people live longer, protecting against the decline in mental function is becoming increasingly important, Professor Ian Robertson, director of the Institute of Neuroscience at Trinity College Dublin, told those attending the British Association for the Advancement of Science meeting in Dublin.
"The biggest threat to being able to function well and properly is our brains," he told journalists.
"There is very strong evidence, particularly in the over-50s, that the degree to which you maintain your mental faculties depends on a handful of quite simple environmental factors," added Professor Robertson.
Aerobic fitness is one of the best ways of boosting activity and structure of brain cells, he said, citing a training programme that showed over 60s had an improved mental ability after only four months, while people who continued such a programme for three years avoided the drop in mental sharpness experienced by people not exercising.
Avoiding high stress levels and continuing a rich, social life are also important, as is healthy diet, said Professor Robertson, citing the role of antioxidants in protecting the brain from ageing.
A fellow Trinity professor, Marina Lynch, further emphasised the role of the diet, pointing to new research into fish oils.
A Scottish study published last year found that cognitive function at age 64 was better in a subgroup of persons who received a fish oil supplement compared with a subgroup which received no supplement.
"Studies have identified the anti-inflammatory properties as well as the restorative qualities of omega-3," she said.
Lynch said the biggest surprise of the latest discovery was that omega-3 appeared not only to replace anti-inflammatories that dwindle with age but also to stem a corresponding rise in chemicals that cause the cell inflammation in the first place.
"These effects seem to cobble together to restore the ability of people to maintain memory as they grow older," added Professor Lynch.
The proportion of the population aged 65 and over has been increasing rapidly in recent decades. In 2000 16 per cent of the population was over 65; it is estimated that this will increase to 24.89 per cent by 2050, said the researcher.