TORONTO • Work that involves complex thinking and interaction with other people seem to help protect against the onset of Alzheimer's disease, according to research presented at the Alzheimer's Association's International Conference in Toronto.

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.

"You can never totally forget about the importance of a good diet, but in terms of your risk of dementia, you are better able to accommodate some of the brain damage that is associated with consuming this kind of (unhealthy) diet," said Mr Matthew Parrott, a post-doctoral fellow at the Rotman Research Institute in Toronto, who presented the study.

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 - could better tolerate WMH-related damage if they worked primarily with other people rather than with things or data.

Jobs involving "mentoring" - such as social worker, physician, school counsellor, psychologist, and pastor - were considered most complex, said Ms Elizabeth Boots, a research specialist at the University of Wisconsin and the study's presenting author. Work involving taking instructions or helping was considered the 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.

THE WASHINGTON POST