Can healthy lifestyle choices help prevent dementia?
By Dr Eider M Arenaza-Urquijo
(posted 16th December 2016)
There is now much evidence to support the idea that healthy lifestyle choices may play an important role in the prevention of Alzheimer’s disease. Studies show that keeping mentally and physically active may offer protection against developing cognitive decline and dementia.
For almost four years, we have been using advanced neuroimaging techniques in our Caen laboratory in order to understand how lifespan mental and physical activities influence our brain, notably in later life. We have used magnetic resonance imaging (MRI) to measure the volume, structure and neural activity of the brain and positron emission tomography (PET), a technique that allows measuring the metabolic activity of the brain.
Several neuroimaging studies point to the idea that mental and physical activities throughout life are related to preserved brain structure and function in later life. In our laboratory, we have studied the brains of a group of people aged between 60 and 80 years old in relation to the number of years they attended school (as an indicator of mental activity early in life). Participants who spent longer at school had more preserved brain tissues, elevated metabolic function and stronger connections between different brain regions. These regions included the hippocampus and the frontal lobe – both especially vulnerable to ageing and Alzheimer’s disease processes. The stronger connections between these areas sustained better performances in functions such as memory or attention in participants who spent longer at school.
So is it ever too late to adopt healthy lifestyle habits? A recent review that collected and analyzed multiple research studies indicates that even making changes later in life could reduce the risk of developing Alzheimer’s disease. In line with this idea, we recently showed that older adults (60-90 years) who are currently more frequently engaged in mental or physical activities – such as reading or playing games, walking or gardening – had larger hippocampal and frontal regions. Notably, both kinds of activities seem to have a positive effect on these brain structures in a complementary way.
Unfortunately, having a healthy lifestyle does not necessarily prevent you from developing Alzheimer’s disease. The development of dementia is a complex process that involves several factors, such as genetics, lifestyle and environment. Studies, however, suggest that positive lifestyle factors may counteract the harmful deleterious effects of genes. In a recent study we observed that people carrying the highest known genetic risk for Alzheimer’s disease but who were highly cognitively engaged, had elevated metabolic function in some brain areas relating to memory performance. Moreover, when Alzheimer’s disease pathology is present in the brain, the brains of individuals with a higher engagement in cognitive and physical activities might be better equipped to compensate for the pathology, meaning that the onset of the symptoms might be delayed.
As part of the Silver Santé Study, we are translating all this promising evidence into a mental training program for adults aged 65 years or older, who will take part in the study for 18 months. This will allow us to observe how their brain structure and function change in response to training. We hope this will provide us with a better understanding of the mechanisms underlying mental activity in later life and how that relates to brain and cognitive health.
Arenaza-Urquijo et al., Neuroimage, 2013 https://www.ncbi.nlm.nih.gov/pubmed/23796547
Arenaza-Urquijo, de Flores et al., Brain Imaging and Behavior, 2016 https://www.ncbi.nlm.nih.gov/pubmed/27757821
Arenaza-Urquijo et al., Neurology, 2015 https://www.ncbi.nlm.nih.gov/pubmed/26408498
Arenaza-Urquijo et al., Frontiers in Aging Neuroscience, 2015 https://www.ncbi.nlm.nih.gov/pubmed/26321944