How soon should you think about preventing dementia?

by Paula Goodyer for The Sydney Morning Harold:

As early as the 20s and 30s and certainly by the time we're in our 40s, according to researchers from the Centre for Healthy Brain Ageing 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-lifespan approach to preventing dementia,'' she says.Maintaining a healthy weight is a start. Gain too many kilograms 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.By the age of 50, many people have gained weight, often beginning in their 30s, but staying at a healthy weight can make a difference to general and brain health later on, Gates says.Healthy habits are no guarantee of evading dementia but can be a big help. About half the risk of dementia is related to lifestyle factors, centre co-director Perminder Sachdev says. Exercise may be the most important protective factor for ageing brains. Ideally, it should start early and be maintained into later life, though 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 judgments], and lower dementia risk,'' Gates says. ''While our brains shrink with age, there's evidence regular exercise can help counteract this by increasing the numbers of brain cells and the connections between them, along with the extra blood flow needed to sustain this new growth.''A mix of aerobic and strength exercises is advantageous because different exercises appear to have different positive effects on the brain.''Aerobic exercise, such as walking, running or cycling, stimulates more of a protein called brain-derived neurotrophic factor that promotes the growth of new brain cells. But resistance training helps the body produce more of a hormone called insulin growth factor 1 that's important for improving the blood supply to the brain,'' Gates says.How can younger people be convinced to start thinking about brain health at an age when dementia is the last thing on their minds? The centre has begun training a team of people in their 20s and 30s as fitness ambassadors to create awareness of the issue. These ambassadors are also encouraging others to take part in fitness events, such as the City2Surf, for their own health's sake and to raise money for research into brain ageing.There could be signs that ageing brains are taking a turn for the better. Following Danish research that showed people in their 90s living in 2010 appeared to be mentally sharper than those of a similar age living in 1998, a recent British study found fewer people than expected were developing dementia in Britain.If these findings hold up in other countries, it could mean lower levels of dementia in the future, says Henry Brodaty, a 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 US, which may have more of an impact on dementia compared with Denmark and the UK.''