This after-meal blood sugar spike may raise Alzheimer’s risk
- Date:
- January 15, 2026
- Source:
- University of Liverpool
- Summary:
- Spikes in blood sugar after eating may be more dangerous for the brain than previously thought. In a massive genetic study, people with higher post-meal blood sugar had a much greater risk of Alzheimer’s disease. The effect couldn’t be explained by visible brain damage, suggesting hidden biological pathways may be involved. Researchers say managing blood sugar after meals could become a key strategy for reducing dementia risk.
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A research team from the University of Liverpool has reported new evidence suggesting that sharp increases in blood sugar following meals may raise the risk of Alzheimer's disease. The findings point to after-meal glucose levels as a potential factor in long-term brain health.
For years, studies have shown that conditions such as hyperglycemia, diagnosed type 2 diabetes mellitus, and insulin resistance are linked to poorer brain health. These metabolic problems have been associated with higher chances of cognitive decline and various forms of dementia. However, exactly how blood sugar disruptions contribute to these brain changes has remained unclear.
Large Genetic Study Using UK Biobank Data
To explore this connection, researchers examined genetic and health information from more than 350,000 UK Biobank participants between the ages of 40 and 69. The analysis focused on key indicators of how the body manages sugar, including fasting glucose levels, insulin levels, and blood sugar measured two hours after eating.
The team used Mendelian randomization, a genetic method that helps researchers assess whether certain biological traits are likely to play a direct role in disease risk. This approach allowed them to test whether different measures of blood sugar regulation could be linked to the development of dementia.
Post-Meal Blood Sugar Linked to Alzheimer's Risk
The analysis showed that individuals with higher blood sugar levels after meals had a 69% higher risk of developing Alzheimer's disease. This specific pattern of elevated glucose, known as (postprandial hyperglycemia), stood out as a key factor.
Importantly, the increased risk was not explained by overall brain shrinkage or damage to white matter. This suggests that elevated after-meal blood sugar may affect the brain through more subtle biological processes that are not yet fully understood.
Implications for Prevention and Future Research
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."
Story Source:
Materials provided by University of Liverpool. Note: Content may be edited for style and length.
Journal Reference:
- Andrew C. Mason, Nasri Fatih, Reecha Sofat, Christopher T. Rentsch, Liam Smeeth, Krishnan Bhaskaran, Nish Chaturvedi, Victoria Garfield. Disentangling the relationship between glucose, insulin and brain health: A UK Biobank study. Diabetes, Obesity and Metabolism, 2025; DOI: 10.1111/dom.70353
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