Diabetes impacts the mind by means of power use, blood vessels, and irritation. Some remedies could gradual or forestall dementia.
The connection between diabetes and dementia is changing into steadily extra evident. Current research spotlight how disturbances in blood sugar regulation can impair mind perform, whereas mind issues can, in flip, have an effect on glucose management. Under are ten research-based findings that designate how the 2 circumstances are intertwined.
1) Diabetes raises the chance of dementia
People with diabetes face roughly a 60% better probability of creating dementia in comparison with these with out the illness. Repeated episodes of low blood sugar are additionally related to a 50% increased likelihood of cognitive decline.
2) Insulin resistance impacts the mind too
Insulin resistance – the principle driver of kind 2 diabetes – happens when cells fail to reply appropriately to insulin. As a result, excess glucose remains in the bloodstream, leading to harmful consequences.
Although this resistance is most often seen in the liver and muscles, it also occurs in the brain. In Alzheimer’s disease, this reduced response to insulin may limit the brain’s ability to use glucose for fuel, contributing to the loss of cognitive abilities.
3) A brain sugar shortage in dementia
While the brain accounts for only 2% of total body weight, it consumes around 20% of the body’s energy. In dementia, nerve cells seem to lose the capacity to effectively use glucose.
This combination of impaired glucose use and insulin resistance has sometimes been informally referred to as type 3 diabetes.
4) Alzheimer’s can raise diabetes risk
People with Alzheimer’s often have higher fasting blood glucose, even if they don’t have diabetes. This is a form of pre-diabetes. Animal studies also show that Alzheimer’s-like changes in the brain raise blood glucose levels.
Also, the highest genetic risk factor for Alzheimer’s, the APOE4 genetic variant, reduces insulin sensitivity by trapping the insulin receptor inside the cell, where it cannot be switched on properly.
5) Blood vessel damage links both conditions
Diabetes damages blood vessels, causing complications in the eyes, kidneys and heart. The brain is also at risk. High or varying blood glucose levels can injure vessels in the brain, reducing blood flow and oxygen delivery.
Diabetes can also weaken the brain’s protective barrier, letting harmful substances in. This leads to inflammation. Reduced blood flow and brain inflammation are strongly linked to dementia.
6) Memantine: a dementia drug born from diabetes research
Memantine, used to treat moderate to severe Alzheimer’s symptoms, was originally developed as a diabetes medication. It didn’t succeed in controlling blood glucose, but researchers later discovered its benefits for brain function. This story shows how diabetes research may hold clues for treating brain disorders.
7) Metformin might protect the brain
Metformin, the most widely used diabetes drug, does more than just lower blood glucose. It gets in to the brain and may lower brain inflammation.
Some studies suggest that people with diabetes who take metformin are less likely to develop dementia, and those who stop taking it may see their risk increase again.
Trials are testing its effects in people without diabetes.
8) Weight-loss injections may reduce plaque buildup
GLP-1 receptors agonist drugs, such as semaglutide (Ozempic, Wegovy), lower blood glucose and support weight loss. Records show that people with diabetes on these drugs have a lower dementia risk. Comparing GLP1 drugs to metformin, studies have found that they were even more effective than metformin at reducing dementia risk.
Two major trials, Evoke and Evoke Plus, are testing oral semaglutide in people with mild cognitive impairment or early mild Alzheimer’s.
9) Insulin therapy might help the brain
Since insulin resistance in the brain is a problem, researchers have tested insulin sprays given through the nose. This method delivers insulin straight to the brain while reducing effects on blood sugar.
Small studies suggest these sprays may help memory or reduce brain shrinkage, but delivery methods remain a challenge. Sprays vary in how much insulin reaches the brain, and long-term safety has not yet been proven.
10) SGLT2 inhibitors may lower dementia risk
New evidence suggests that compared to GLP-1 receptor agonists, SGLT2 inhibitors, (a type of diabetes drug) are superior at reducing dementia risk, including Alzheimer’s and vascular dementia, in people with type 2 diabetes. These tablets lower blood sugar by increasing sugar removal in urine. This study builds on early evidence suggesting they lower dementia risk by reducing inflammation in the brain.
This growing body of evidence suggests that managing diabetes protects more than the heart and kidneys, it also helps preserve brain function.
Questions remain whether diabetes drugs only reduce the diabetes-associated dementia risk or whether these drugs could also reduce risk in people without diabetes.
However, diabetes research has been very successful in creating at least 13 different classes of drugs, multiple combination therapies, giving rise to at least 50 different medicines. These reduce blood sugar, improve insulin sensitivity and reduce inflammation. A “side-effect” may be better preservation of brain health during aging.
Written by:
- Craig Beall, Associate Professor in Experimental Diabetes, University of Exeter
- Natasha MacDonald, PhD Candidate, Biochemistry, University of Exeter
Adapted from an article originally published in The Conversation.
Craig Beall currently receives funding from Diabetes UK, Breakthrough T1D, Steve Morgan Foundation Type 1 Diabetes Grand Challenge, Medical Research Council, NC3Rs, Society for Endocrinology and British Society for Neuroendocrinology.
Natasha MacDonald receives funding from Diabetes UK.
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