Exercise and healthy diets associated with better cognitive functioning

Findings published this week in the Journal of Public Health reveal that both younger and older Canadian adults who engage in regular physical activity, consume more fruits and vegetables and are normal weight or overweight have overall better cognitive functioning.

Regular engagement in physical activity and healthy eating has long been associated with a reduced risk for a range of chronic conditions. For older adults, there is a growing body of evidence that exercising may delay the onset of cognitive decline. Similarly, compounds found in fruits and vegetables have been shown to fight illnesses and help maintain healthy processes in the body. Given the increasing rates of inactivity and obesity in the world, researchers are interested in understanding the relationship between clusters of risk factors for cognitive decline, and how lifestyle factors might help prevent or delay it.

Previous studies in Spain and Korea have shown that older adults who eat more fruits and vegetables perform better in mentally stimulating activities than older adults who report eating a lower amount. However, very few studies have investigated the relationships between physical activity and eating fruit and vegetables and the effect it has on the brain for both younger and older adults.

This study examined cross-sectional data from 45,522, 30 years of age and older, participants from the 2012 annual component of the Canadian Community Health Survey. Cognitive function was assessed using a single 6-level question of the Health Utilities Index, which assessed mental processes, such as thinking, memory, and problem solving. Participants were analyzed by their age, level of physical activity, body mass index, and daily intake of fruit and vegetables. Using general linear models and mediation analyses, researchers assessed the relationship between these factors and participants' overall cognitive function.

The results showed that higher levels of physical activity, eating more fruits and vegetables, and having a BMI in the normal weight (18.5-24.9 kg/m2) or overweight range (25.0-29.9 kg/m2) were each associated with better cognitive function in both younger and older adults. Further, by way of mediation analysis (via the Sobel test), it was determined that higher levels of physical activity may be in part responsible for the relationship between higher daily fruit and vegetable consumption and better cognitive performance.

Dr. Alina Cohen, PhD, explains: "Factors such as adhering to a healthy lifestyle including a diet that is rich in essential nutrients, regular exercise engagement, and having an adequate cardiovascular profile all seem to be effective ways by which to preserve cognitive function and delay cognitive decline." Further that "It is pertinent that we develop a better understanding of the lifelong behaviors that may contribute to cognitive decline in late life by implementing a life-span approach whereby younger, middle-aged, and older adults are collectively studied, and where lifestyle risk factors are evaluated prior to a diagnosis of dementia."