The population is ageing, and the older we become the more likely it is that we risk deterioration of our cognitive functions, such as memory, decision-making and problem solving. Research indicates several possible contributors to these changes, with several studies demonstrating an association between not having teeth and loss of cognitive function and a higher risk of dementia.
One reason for this could be that few or no teeth makes chewing difficult, which leads to a reduction in the blood flow to the brain. However, to date there has been no direct investigation into the significance of chewing ability in a national representative sample of elderly people.
Now a team comprised of researchers from the Department of Odontology and the Aging Research Center (ARC) at Karolinska Institutet and from Karlstad University have looked at tooth loss, chewing ability and cognitive function in a random nationwide sample of 557 people aged 77 or older. They found that those who had difficulty chewing hard food such as apples had a significantly higher risk of developing cognitive impairments. This correlation remained even when controlling for sex, age, education and mental health problems, variables that are often reported to impact on cognition. Whether chewing ability was sustained with natural teeth or dentures also had no bearing on the effect.
The results are published in the Journal of the American Geriatrics Society (JAGS). The study was financed with grants from several funds, including the Swedish Council for Working Life and Social Research and the Swedish Research Council.
Duangjai Lexomboon, Mats Trulsson, Inger Wårdh & Marti G. Parker Chewing Ability and Tooth Loss: Association with Cognitive Impairment in an Elderly Population Study
Journal of the American Geriatrics Society, online ahead of print 4 October 2012