Sharp rises in blood sugar after meals may raise Alzheimer’s risk, according to genetic analysis of more than 350,000 adults.
The findings point to after-meal glucose, rather than overall blood sugar, as a possible factor in long-term brain health.
Researchers examined genetic and health data from over 350,000 UK Biobank participants aged 40 to 69, focusing on fasting glucose, insulin, and blood sugar measured two hours after eating.
The team used Mendelian randomisation, a genetic method that helps test whether biological traits may play a direct role in disease risk.
People with higher after-meal glucose had a 69 per cent higher risk of Alzheimer’s disease.
This pattern, known as postprandial hyperglycaemia (elevated blood sugar after eating), stood out as a key factor.
The increased risk was not explained by overall brain shrinkage (atrophy) or white matter damage, suggesting after-meal glucose may affect the brain through other pathways not yet fully understood.
Dr Andrew Mason, lead author, said: “This finding could help shape future prevention strategies, highlighting the importance of managing blood sugar not just overall, but specifically after meals.”
Dr Vicky Garfield, senior author, added: “We first need to replicate these results in other populations and ancestries to confirm the link and better understand the underlying biology.
“If validated, the study could pave the way for new approaches to reduce dementia risk in people with diabetes.”
