Two studies looked at how complex work and social engagement counteract the effects of unhealthy diet and cerebrovascular disease on cognition.
One found that while a "Western" diet (characterised by red and processed meats, white bread, potatoes, pre-packaged foods, and sweets) is associated with cognitive decline, people who ate such food could offset the negative effects and experienced less cognitive decline if they also had a mentally stimulating lifestyle.
Occupations that afforded the highest levels of protections included lawyer, teacher, social worker, engineer and doctor; the fewest protections were seen among people who held jobs such as labourer, cashier, grocery shelf stocker, and machine operator.
In another study, researchers found that people with increased white matter hyperintensities (WMHs) - white spots that appear on brain scans and are commonly associated with Alzheimer's and cognitive decline - were able to better tolerate WMH-related damage if they worked primarily with other people rather than with things or data.
Occupations involving "mentoring" - such as social worker, physician, school counsellor, psychologist, and pastor - were considered most complex, said Elizabeth Boots, a research specialist at the University of Wisconsin and the study's presenting author.
Work involving taking instructions or helping was considered least complex. The study, conducted by the Wisconsin Alzheimer's Disease Research Centre and Wisconsin Alzheimer's Institute, focused on people who were cognitively healthy but at risk for Alzheimer's.
"By showing that cognitive reserve is already at work early in the disease process, we believe this could have potential implications for early intervention, such as identifying those with potentially lower reserve and suggesting ways to boost that reserve in some way," Boots said, adding that it could be possible for those with lower reserve to implement more complex skills into their daily lives."
Staying intellectually active whether it be your job or other kinds of activities may actually be beneficialThe studies support previous findings that more stimulating lifestyles are associated with better cognitive outcomes later in life, and bolster the importance of intellectual engagement, said Ronald Petersen, director of the Mayo Clinic Study of Ageing and the Mayo Alzheimer's Research Centre.
"Physical activity has been reasonably well-documented, but with intellectual activity the data get pretty soft. . .these two studies speak to that," he said. "What it may mean is the development of Alzheimer's Disease or cognitive change with ageing need not be a passive process; you can do something about it. . .staying intellectually active whether it be your job or other kinds of activities may actually be beneficial."
When it comes to training your brain, speed may be more important than content. Researchers at AAIC presented 10-year results from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study, which looked at the impact of different kinds of brain training on 2785 older adults across the US.
They were divided into three groups who received classroom-based memory strategies, classroom-based reasoning strategies, and computerised speed-of-processing training, along with a control group. The groups had 10 60-minute training sessions over five weeks, and some received booster sessions a year and three years after the training.
After 10 years, only the speed-of-processing group showed an effect: a 33 per cent reduction in new cases of cognitive impairment or dementia, which rose to 48 per cent among those who had participated in the booster session. The other two training groups did not show a significant difference from the control group.