With new evidence demonstrating how blood sugar issues impact on the brain and vice versa, there is growing evidence of the link between diabetes and dementia.
There are a number of evidence-based findings that indicate the association between diabetes and dementia.
The first is risk – studies have shown that people with diabetes have a 60% greater risk of developing dementia and people who experience regular low blood sugar have a 50% increased risk of cognition decline.
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Another insight is how insulin resistance affects the brain. Too much sugar in the blood can affect the brain, and for people with Alzheimer’s disease, insulin resistance can make it difficult for brain cells to use glucose as a source of energy, resulting in a decline in cognitive function.
In addition, in people with dementia, brain cells may also lose the ability to use glucose properly. This, combined with insulin resistance, is referred to unofficially as type 3 diabetes.
Insulin sprays, developed to deliver insulin straight to the brain, may also boost memory or lessen brain shrinkage, although long-term safety of this treatment has not yet been tested.
Another key finding is that people with Alzheimer’s commonly have higher fasting blood glucose, even without diabetes, which is a type of pre-diabetes. A significant risk factor for Alzheimer’s, the APOE4 genetic variant, impairs insulin sensitivity.
Another factor linking diabetes and dementia is blood vessel damage. Diabetes harms blood vessels, which can reduce blood flow in the brain’s blood vessels.
Additionally, diabetes can impair the brain’s protective barrier which can lead to inflammation, something that is linked to dementia.
The role of medication has shed further light on the link between diabetes and dementia. The drug memantine was originally developed as diabetes drug and while it didn’t work at managing blood sugar, benefits for brain function were found. This demonstrates how diabetes research could lead to discoveries in cognitive function.
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Another diabetes drug, metformin, has been shown to potentially reduce brain inflammation, with some research highlighting how people taking the drug are less at risk of developing dementia.
Another treatment, GLP-1 weight loss jabs, has shown to reduce dementia risk, while trials are ongoing to test the effects of this medication on individuals with mild cognitive impairment or early mild Alzheimer’s.
New research has identified that SGLT2 inhibitors may reduce the risk of dementia in those with type 2 diabetes, with experts saying they may work by reducing inflammation in the brain.
What is still not clear is whether diabetes drugs only reduce dementia risk in people with diabetes or whether they would benefit people without diabetes.
