Most people dismiss this common health condition as harmless—just something to “keep an eye on.” But shocking new research reveals it may already be silently aging your brain, putting you on a fast track to memory loss and cognitive decline. Even more surprising? The damage can continue—even if your numbers look “normal” on the surface. Fortunately, scientists have also uncovered simple lifestyle shifts that can slow down, or even reverse, this hidden brain-aging process. Keep reading to find out what might be sabotaging your memory—and how to take back control.
Key Takeaways
- Prediabetes Ages the Brain – People with prediabetes showed signs of brain aging before any symptoms of cognitive decline.
- Lifestyle Matters – High physical activity and healthy habits significantly reduced brain aging, even among diabetics.
- Diabetes = Higher Dementia Risk – Controlled diabetes aged the brain by 2.3 years, and uncontrolled diabetes aged it by over four years.
The Shocking Link Between High Blood Sugar and Memory Problems
Rates of diabetes have exploded to such an extent that it now affects between a quarter and a third of seniors.
This disease increases your risk of heart disease, stroke, kidney disease, and much else. But it also has an even darker side. It doubles the risk of dementia and increases brain aging.
There’s no question type-2 diabetes is a serious risk factor for cognitive decline, which is why dementia is sometimes referred to as type-3 diabetes. Even people with prediabetes, which affects more than a quarter of the population, have a much greater risk of cognitive decline and vascular dementia.
The Hidden Brain Crisis in Diabetes
When doctors scan the brains of people with diabetes using MRI technology, they discover something alarming: the brain is quietly deteriorating even before any memory problems or confusion appear. These scans reveal that diabetic brains are actually shrinking, developing damage to tiny blood vessels, and accumulating microscopic injuries throughout the tissue. It's like watching a house slowly crumble from the inside while the exterior still looks fine.
When Your Brain Ages Faster Than You Do
Perhaps even more concerning is what scientists call "accelerated brain aging"—essentially, your brain becoming older than it should be based on how many birthdays you've celebrated. Researchers can now calculate something called a "brain age gap" by comparing how old your brain looks on scans versus your actual chronological age. When this gap widens, it signals trouble ahead: higher chances of memory loss, dementia, and even a shortened lifespan.
The Promise of Early Detection
The exciting news is that if doctors could catch this accelerated aging early enough, they might be able to intervene before serious damage occurs. New computer modeling techniques can now estimate your brain's biological age by analyzing various features visible on MRI scans—the same types of changes already documented in diabetic patients. This could open the door to preventive treatments that slow or even stop this premature brain aging process.
While numerous studies had already connected diabetes to faster brain aging, they all suffered from the same limitation: they only captured a snapshot in time, like taking a single photograph instead of filming a movie. What researchers really needed was to follow people over many years to see how their brains changed. Additionally, no one had investigated whether prediabetes—that warning stage before full diabetes—also affects brain aging, or whether healthy lifestyle choices could protect the brain from blood sugar damage.
Recognizing these critical knowledge gaps, a team of researchers from the prestigious Karolinska Institute in Stockholm, Sweden decided to tackle these unanswered questions head-on. They set out to conduct the kind of long-term, comprehensive study that could finally reveal whether prediabetes threatens brain health and whether lifestyle interventions could serve as a shield against diabetes-related brain aging.2
Prediabetes Isn’t “Mild”—It’s Accelerating Brain Decline
Their study included 31,229 dementia-free British adults aged between 40 and 70. At the start of the study detailed information was obtained on their medical history and blood sugar levels, finding that 43.3% had prediabetes and 3.7% had diabetes.
Data was also collected on cardiometabolic risk factors (obesity, high blood pressure, harmful levels of blood fats), and lifestyle behaviors (smoking, drinking, and physical activity).
All participants underwent up to two brain MRI scans over 11 years of follow-up, and brain age was estimated using a machine learning model to calculate the brain age gap.
The findings showed:
- Prediabetics had a brain age gap of six months
- Diabetics (controlled diabetes) had a brain age gap of 2.3 years
- Diabetics (uncontrolled diabetes) had a brain age gap of more than four years
- The brain age gap increased over time in people with diabetes
- The gap was higher in those with more cardiometabolic risk factors
- Men had a higher gap than women for both prediabetes and diabetes
The gap was reduced among people with high physical activity who abstained from smoking and heavy alcohol consumption. The findings confirmed the results of earlier studies showing diabetes accelerates brain aging, but they’ve now revealed much more.
Lifestyle is The Key to Defeating Diabetes
In addition, as they wrote in Diabetes Care, “our results provide compelling evidence that prediabetes may accelerate brain aging during the very earliest stages of dementia development.[and] emphasize the significance of a healthy lifestyle for not only cardiometabolic health but also the brain.”1
Abigail Dove, who led the research, said: “Having an older-appearing brain for one’s chronological age may constitute an early warning sign for dementia. On the positive side, it seems that people with diabetes may be able to influence their brain health through healthy living.”
Although participants’ exercise data was included in the study and is an important part of a healthy lifestyle, their diet wasn’t featured in the study, yet this is key to reversing diabetes and preventing prediabetes from advancing to diabetes.
As physician scientist Professor Nita Gandhi Forouhi from the University of Cambridge writes: “Nutrition therapy has been emphasized for decades for people with type 2 diabetes, and the vital importance of diet and nutrition is now also recognized for type 2 diabetes prevention.”3
Two successful methods of reversing diabetes we’ve previously featured are a low carb diet or low calorie diet.
Summary
A large-scale study from Sweden’s Karolinska Institute shows that both prediabetes and type 2 diabetes accelerate brain aging, increasing dementia risk. Using brain MRIs and machine learning to calculate “brain age gaps,” researchers found that individuals with prediabetes had a brain age six months older than their actual age, while those with uncontrolled diabetes showed gaps over four years. However, healthy lifestyle habits like regular exercise, not smoking, and limiting alcohol were shown to reduce the brain age gap, offering hope for prevention and reversal.
Frequently Asked Questions
What is the brain age gap?
It’s the difference between your brain’s biological age and your actual chronological age. A larger gap means accelerated brain aging.
How does diabetes affect brain aging?
Diabetes causes brain shrinkage, vascular changes, and lesions, all contributing to cognitive decline and increased dementia risk.
Can prediabetes also cause brain aging?
Yes. Even before full-blown diabetes develops, people with prediabetes show measurable increases in brain age.
What lifestyle changes help reduce brain aging?
Regular physical activity, avoiding smoking, and limiting alcohol consumption have all been shown to reduce the brain age gap.
Can brain aging from diabetes be reversed?
While full reversal is uncertain, the study suggests a healthy lifestyle can slow or potentially reverse some of the brain aging effects.
- Dove A, et al. Diabetes, Prediabetes, and Brain Aging: The Role of Healthy Lifestyle. Diabetes Care. 2024 Oct 1;47(10):1794-1802.
- Karolinska Institutet. A healthy lifestyle may counteract diabetes-associated brain ageing. 04-09-2024.
- Forouhi NG. Embracing complexity: making sense of diet, nutrition, obesity and type 2 diabetes. Diabetologia. 2023 May;66(5):786-799.
Michael Sellar
Michael Sellar is a British writer who has spent over 30 years in the natural health industry. He has worked as a consultant nutritionist, lecturer to natural health professionals, newsletter editor, and writer. He also created and managed a website for twenty years promoting the work of natural therapists in his local community. He lives in rural England.
