Dementia might not strike until late in life, but the problems that increase the risk start earlier than we think. Photo: Getty
How soon should you think about preventing dementia? As early as the 20s and 30s and certainly by the time we're in our 40s, say researchers from the Centre for Healthy Brain Ageing (CHeBA) at the University of NSW.
"Dementia might not take hold until later in life but the accumulated insults to the brain that can contribute to its onset can begin decades before," says clinical neuropsychologist Nicola Gates who believes we need a loud message about maintaining brain health that targets people long before they reach their 60s. "People don't realise they can start influencing how well their brain ages from a young age – it's time we took a whole-of-life-span approach to preventing dementia."
Staying at a healthy weight is a start. Gain too many kilos and up goes the risk of high blood pressure. This can damage blood vessels including those that feed the brain – which is why healthy blood pressure lowers your dementia risk. Being overweight also increases the chances of type 2 diabetes, adding a further risk for developing dementia.
By the age of 50 many people have gained weight - often kilos that began creeping on at 30. But staying at a healthy weight can make a difference to both general health and brain health later on, says Gates.
Healthy habits are no guarantee of evading dementia, but they're a big help. Around half the risk of dementia is related to lifestyle factors, says Professor Perminder Sachdev, co-director of CHeBA who says that exercise may be the most important protective factor for ageing brains. Ideally it should start early and be maintained into late life – although it's never too late to start.
"People who exercise have better cognitive function, especially memory and executive function (the brain skills involved in organisation, planning and judgements), and lower dementia risk," adds Gates. "While our brains shrink with age, there's evidence that regular exercise can help counteract this by increasing both the numbers of brain cells and the connections between them, along with the extra blood flow needed to sustain this new growth."
There's an advantage for doing a mix of aerobic and strength exercises because different exercises appear to have different positive effects on the brain.
"Aerobic exercise like walking, running or cycling stimulates more of a protein called brain-derived neurotrophic factor (or BDNF) that promotes the growth of new brain cells. But resistance training helps the body produce more of a hormone called insulin growth factor 1 (IGF-1) that's important for improving the blood supply to the brain," she says.
How do you convince younger people to start thinking about brain health at an age when dementia is the last thing on their minds? CHeBA has started the ball rolling by training a team of people in their 20s and 30s as 'fitness ambassadors' to create awareness of the issue in the media and among their peers. These ambassadors are also encouraging others to take part in fitness events like the City2Surf for their own health's sake and to raise funds for research into brain ageing.
But there could be signs that ageing brains are taking a turn for the better. Just after Danish research reported that people in their 90s living in 2010 appear to be mentally sharper than 90-somethings living in 1998, a recent British study found that fewer people than expected were developing dementia in the UK.
If these findings hold up in other countries, it could mean less dementia in the future, says Professor Henry Brodaty, Scientia Professor of Ageing and Mental Health at the University of NSW.
"The implication is that environmental factors may be leading to this reduction - mainly better education levels," he says. "However, we have an epidemic of diabetes and obesity in Australia and the USA which may have more of an impact on dementia compared to Denmark and the UK."
The Centre for Healthy Brain Ageing is still recruiting more Fitness Ambassadors Australia-wide. If you're passionate about fitness and spreading the word about dementia prevention email firstname.lastname@example.org or call (02) 9382 3398.