A diet high in sugar not only leads to diabetes and obesity but now researchers have revealed it can stop a protein from working efficiently.
Experts have confirmed there are biological links between dementia and high blood sugar.
Researchers at University of Bath compared brain samples of 30 people with and without Alzheimer’s disease and tested them for protein glycation, a modification caused by high glucose levels in the blood.
The team found that a particular enzyme was glycated in the brains of people with Alzheimer’s disease and that glycation stopped the enzyme from working properly.
The enzyme, known as ‘macrophage migration inhibitory factor’ or MIF, has been previously implicated in the inflammatory response that occurs in the brains of people with Alzheimer’s disease.
Dr Clare Walton, Research Manager at Alzheimer’s Society said: “We know that diabetes can double a person’s risk of developing dementia but we still don’t really understand how the two conditions are linked - this study offers a vital clue.
The researchers have found a specific effect of high blood glucose on an enzyme in the brains of people with Alzheimer’s, providing a plausible biological mechanism connecting the two conditions.
“With diabetes on the rise, a better understanding of how it affects brain cells can help us to find ways to help people with diabetes manage their risk of dementia.
“Alzheimer’s Society is currently funding a clinical trial to see whether a diabetes drug can be used as a dementia treatment.”
Professor Jean van den Elsen, from Bath's Department of Biology and Biochemistry, said: "We've shown that this enzyme is already modified by glucose in the brains of individuals at the early stages of Alzheimer's disease. We are now investigating if we can detect similar changes in blood.
"Normally MIF would be part of the immune response to the build-up of abnormal proteins in the brain, and we think that because sugar damage reduces some MIF functions and completely inhibits others that this could be a tipping point that allows Alzheimer's to develop.
Dr Rob Williams, also from the Department of Biology and Biochemistry, added: "Knowing this will be vital to developing a chronology of how Alzheimer's progresses and we hope will help us identify those at risk of Alzheimer's and lead to new treatments or ways to prevent the disease.
Every week 4,500 people are diagnosed with diabetes across the UK.
Type 2 diabetes occurs when the body does not produce enough insulin or the insulin produced does not work properly.
The condition, which can be caused by being overweight and poor diet can cause blindness, limbs to be amputated and even kidney failure.