While blood sugar has always been an indication of our dietary health, these new findings reveal that it could also affect our brain function and cognition as we age.
The study, led by epidemiologist Wuxiang Xie from Imperial College London, tracked 5,189 people – 55 per cent women, with an average age of 66 years – and assessed their cognitive function alongside their HbA1c, or glycated haemoglobin, levels between 2004-2005 to 2014-15.
HbA1c measures blood sugar control over time so can be a more accurate source of information on the stability of a person’s blood sugar levels and how well they are being managed.
While all participants in the study showed a level of cognitive decline over the course of the study related to ageing, researchers found that those with greater levels of HbA1c experienced an increased rate of decline.
While previous studies have shown a similar link between diabetes and conditions such as Alzheimer’s, this is the first study to use HbA1c levels, indicating a link between higher blood sugar levels and cognitive decline, whether or not the person is technically diabetic or not.
Alzheimer’s Research UK’s Chief Scientific Officer David Reynolds told Science Alert that while the study showed a correlation between blood sugar control and cognitive decline there was still work to be done.
“One strength of this large study is that it followed people over time to show a faster decline in memory and thinking in those with poorer blood sugar control,” says Mr Reynolds.
“But it does not shed any light on the potential mechanisms underlying this decline.”
While work is still underway to understand these underlying factors, the study findings, published in Diabetologia, provides the best indication we have that diets high in sugar can cause harm to not just the body but the mind as well.