Learning about dementia and how to keep our brains healthy as we age is a never-ending task for Canadian researchers.

Earlier this week, Vancouver hosted a conference that brought together clinicians and experts for the country’s largest dementia research initiative, the Canadian Consortium on Neurodegeneration in Aging (CCNA) .

Dr. Howard Chertkow, one of the country’s leading brain health researchers, says there are a lot of things people can do to not only protect their brains but keep them healthy as they age.

Chertkow, the CCNA’s scientific director and co-scientific director of Baycrest’s Kimel Family Centre for Brain Health & Wellness in Toronto, said physical activity such as aerobic exercise – at least 150 minutes a week – is important.

“Walk to the store rather than driving,” he said in an interview conducted by email. “Get your weight down to where you know it should be.”

He also suggests being social as well as eating and sleeping well. In addition, people should immediately treat any physical, vascular or mental health conditions including high blood pressure, diabetes and depression.

“Many of the strategies serve to build up cognitive reserve and brain resilience, and the other strategies help fight deposition of toxic proteins in the brain,” he said.

The following is a Q&A with Chertkow on what is known and unknown about dementia and brain health:

What has research found about the link between biological stress and dementia?

Stress is different for each individual. What stresses one person is tolerable to another. However, it is quite clear that people under chronic stress have brain changes (shrinkage of brain areas related to high cortisol levels, for instance) and also have increased risk of developing dementia. For instance, older people looking after a spouse with a serious chronic disease (such as dementia) themselves are at higher risk of developing early dementia themselves.

But stress isn’t the only risk – people who are lonely, people who report lacking a “sense of purpose” in their life, people who are depressed – all of these are associated with increased risk of developing dementia. The underlying biology of these associations remains obscure, but the implication is clear – any program aimed at preventing dementia must not ignore the social dimensions of aging.

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Does chronic inflammation play a role in cognitive decline?

There are two important aspects to chronic inflammation – what is going on in the body and what is going on in the brain. In the brain there is research (a lot of it from Canadian researchers) that Alzheimer disease is characterized by activation of “innate” inflammatory cells such as microglia, which has a deleterious effect. Without such activation, the cascade of processes causing Alzheimer disease dementia is far less likely to occur. Current work is focused on understanding if there are approaches for therapy that “cool” this deleterious neuroinflammation.

At the same time, there is a phenomenon of low level inflammation in older individuals in the body (outside the brain) that may be a second pathway affecting the health of brain cells. This “ inflammaging ” discharges inflammatory chemicals called cytokines into the blood, and these can reach the brain as well. The presence of these cytokines is much more likely to be found in individuals with dementia than those with normal thinking. So what causes the peripheral inflammation? The biggest driver appears to be obesity, although poor diet, poor sleep, smoking, and exposure to pollution can also be factors. Exercise and weight loss are the most effective interventions to reduce the inflammation seen in the blood. Brain diets like the MIND diet may also help reduce inflammation.

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Does excess body fat influence the health of our brains?

Yes, absolutely! As mentioned above, peripheral inflammation plays a role in cognitive decline in the brain and the biggest driver of this appears to be obesity. Furthermore, we know that most dementias are a combination of bad proteins (which cause Alzheimer’s disease and Lewy body dementia) and bad blood flow (causing so called vascular dementia). And diabetes as well as pre-diabetes are big drivers of bad blood flow in older people. So to the extent that obesity predisposes to diabetes, it will affect the brain blood flow and contribute in an important way to cognitive decline.

How important is laughter to cognitive health?

A positive mental attitude, less neuroticism, less stress, less depression, less anxiety all statistically reduce the chance of developing dementia. At the CCNA conference, we had a session of Laughter Yoga, to get the participants in the mood for networking and socializing. Laughing certainly feels good. Can such strategies promoting laughter actually affect long term cognitive health? This remains to be shown.