Blood sugar spikes linked to higher risk of Alzheimer's disease: Study

A new study led by researchers from the University of Liverpool has found that spikes in blood sugar after meals may increase the risk of Alzheimer's disease.

Whilst research has long suggested that hyperglycaemia, diagnosed type 2 diabetes mellitus and insulin resistance strongly relate to worse brain health, specifically increasing the risk of cognitive decline and dementias, the underlying mechanisms are poorly understood.

Using data from the UK Biobank, the team analysed genetic data from over 350000 individuals aged between 40 and 69 years of age. They focused on markers of how the body processes sugar, including fasting glucose, insulin levels and blood sugar measured two hours after eating. Using a technique called Mendelian randomisation, they tested whether these traits were likely to play a causal role in dementia risk.

The results found that people with higher post-meal blood sugar (postprandial hyperglycaemia) had a 69% greater risk of developing Alzheimer's disease. This was not explained by changes in overall brain size or damage to white matter, suggesting that the risk may operate through more subtle mechanisms.

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 commented: “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.”

Reference:

Andrew C. Mason et al, Disentangling the relationship between glucose, insulin and brain health: A UK Biobank study, Diabetes, Obesity and Metabolism (2025). DOI: 10.1111/dom.70353