WHAT'S GOOD FOR THE BODY IS GOOD FOR THE BRAIN!

Scientists have known since the 1970s that a good bout of exercise boosts cognition in the short term. But recent research has discovered that cardiovascular health plays a huge role in dementia risk.

“What’s good for the heart is good for the brain,” says Yves Joanette, scientific director of the Canadian Institutes of Health Research’s Institute of Aging. “You have two for the price of one, if you exercise and eat well.”

One 2011 meta-analysis found that those who exercised more than three times a week decreased their risk of dementia by 38 per cent. Another published in 2014 reported that those who stuck closely to the heart-healthy Mediterranean diet had 33 per cent less risk of cognitive impairment compared to those who ate that way the least often.

These numbers are “huge,” says Louis Bherer, scientific director of the PERFORM Centre at Concordia University, a facility devoted to prevention and healthy lifestyle research. “There is no comparable intervention or pills you can take right now to protect you better than that.”

As in most things dementia-prevention, when it comes to exercise there’s no such thing as too soon. In Finland, researchers have been following 2,000 individuals who were middle-aged when they signed up in the 1970s and ’80s. In 1998, the scientists re-examined them. The participants who were physically active in their leisure time at least twice a week in middle age were 50 per cent less likely to develop dementia in later life compared to those who were sedentary, even after controlling for other risk factors.

Troubling research from the U.S. hints that the link between physical activity and brain health starts far earlier. In a study of 30 obese and 30 lean adolescents, New York University School of Medicine researchers found that the obese teens scored lower on mental flexibility and attention tests and had lower academic achievements. MRI scans uncovered subtle changes in their brain structure. (The researchers were examining the link between obesity in twins and brain abnormalities, not dementia risk.)

But there’s no such thing as too late, either. A Canadian research team co-led by Bherer and Francis Langlois found that a three-month exercise intervention improved both physical and cognitive function in frail elderly adults.

“I would start as soon as possible,” says Bherer. He jokes with his university students that they can remain couch potatoes for now, “but when you’re 45, you don’t have a choice anymore. If you want to save your brain, you’ve got to kick your ass.”

The same trends emerge in research on diet and cognition. Another report from the Finnish group found that mid-life cardiovascular risk factors such as obesity and hypertension — which diet and exercise can help control — increase the risk of later-life cognitive impairment. Older adults who switch to a Mediterranean diet — high in vegetables, fruit, nuts, legumes, fish and whole grains; low in saturated fat and red meat; moderate intake of alcohol — show better cognition scores and slower mental decline.

Carol Greenwood, a professor at the University of Toronto’s department of nutritional sciences and a senior scientist at Baycrest, notes that scientists have been frustrated when trying to study the effects of individual nutrients like antioxidants: nothing seem to offer the same benefits as an overall healthy diet.

“We want people not to focus on an individual food but what the plate looks like,” she says. “People are going from blueberries yesterday to pomegranate today to kelp and fish today. It’s confusing: they’re being bombarded.”

Yet the fundamentals of a healthy diet have not budged, and Greenwood argues that “Mediterranean diet” is a misnomer. Cuisines worldwide, from Asia to Africa, feature the same plant-based focus, and all of these are easy to recreate in a big city.

“You don’t have to live on an idyllic Greek isle,” she says.