Why Controlling Insulin Resistance May Be Key to Slowing Brain Aging

Insulin Resistance

Brain health is a critical component of wellness. A healthy brain enables us to remember, learn, and think clearly. Where would we be without those skills? Brain health is most important for mental wellness, which affects the quality of life. So, it’s important to do what’s possible, based on current knowledge, to preserve brain health.

Brain aging is a complex process and one that scientists don’t fully understand but we do know what some risk factors are for dementia. A head injury can cause brain damage and increase the risk of dementia later and genetics are a factor, but lifestyle habits also play a role.

Scientists are discovering that insulin resistance–a condition linked with high blood sugar levels—can promote cognitive decline. Fortunately, lifestyle plays a role in insulin sensitivity and in preventing insulin resistance. Let’s look at how insulin resistance contributes to brain aging and why improving insulin sensitivity could help you stay mentally healthier.

Insulin Resistance Is Shockingly Common

Did you know that insulin resistance affects almost 10% of people worldwide? The biggest risk factor for insulin resistance is obesity, but genetic predisposition, stress, lack of sleep, and certain medications can also accelerate brain aging and increase the risk of dementia. When cells are resistant to insulin, glucose stays in your bloodstream longer and, eventually, it can lead to prediabetes and type 2 diabetes.

Insulin Resistance is a Precursor to Type 2 Diabetes

You hear a lot about insulin resistance, but what is it? Insulin resistance is a condition in which cells do not respond optimally to insulin. Insulin is an important hormone that helps ferry glucose from your bloodstream into cells where they can use it to make energy. Glucose is beneficial inside a cell as an energy source, but damaging and harmful to your health when too much stays in your bloodstream.

With insulin resistance, too much glucose hangs out in your bloodstream because your cells don’t respond as well to insulin. Your pancreas releases higher amounts of insulin to compensate for the impaired insulin response but eventually, it can’t keep up with the demand and blood sugar levels begin to rise. With insulin resistance, your blood glucose is higher than normal, but not at the level of type 2 diabetes. At this stage, it’s called prediabetes. But insulin resistance can progress to full-blown type 2 diabetes. Plus, insulin resistance can also cause a rise in blood pressure and increase the risk of cardiovascular disease.

Insulin Resistance Affects Many Organs

Insulin resistance affects all major organs in your body: your liver, kidneys, heart, and muscles, as well as your brain. So, it’s not just your waistline that suffers when you’re insulin resistant. Your brain is also not immune to insulin resistance. It needs insulin to function properly, as the brain is an insulin-sensitive organ.

Brain cells rely on sugar as their primary fuel source, and they require ample supply to function properly. Your brain is one of the major consumers of glucose, so insulin resistance also affects its activity and even how it ages. Plus, insulin resistance is a precursor to diabetes and heart disease, making it an important health issue that you should discuss with your doctor.

Insulin resistance and the Risk of Dementia

You may be surprised to learn that insulin resistance and diabetes are risk factors for developing dementia. This includes Alzheimer’s disease and vascular dementia (the second most common type of dementia). It’s less clear whether insulin resistance affects other types such as frontotemporal dementia, Lewy body disease (which accounts for about 20% of all dementias), and mixed dementia. The link between Alzheimer’s and type 2 diabetes is so strong that some people refer to Alzheimer’s disease as type 3 diabetes.

Studies show that people with diabetes have a higher prevalence of dementia than those without it–and the link is even stronger in women than men. This suggests that women with type 2 diabetes may be at greater risk for cognitive impairment than men with poor blood sugar control.

Does Taming Insulin Resistance Reduce the Risk of Dementia?

There’s growing evidence that maintaining a healthy blood glucose level helps prevent dementia and supports brain health. Healthy blood sugar management promotes the growth of new brain cells and helps keep existing ones healthy. Plus, it can help you focus better and improve memory retention by enhancing communication between neurons in your brain.

Maintaining healthy blood sugar also improves mood and reduces feelings of anxiety. Blood sugar fluctuations can cause rapid spikes and falls in blood glucose that affects your mental health and mood.

Studies also show that people with Alzheimer’s disease have impaired insulin function and that drugs used to treat diabetes can improve some markers of brain function at the cellular level. Those are all good reasons to improve how your cells respond to insulin, right?

Strategies for reducing insulin resistance:

  • Maintain healthy body weight. Obesity is the number one risk factor for insulin resistance.
  • Eliminate refined carbohydrates from your diet and eat more fiber-rich foods, including fruits and vegetables.
  • Meet the recommended guidelines for physical activity — at least 30 minutes of moderate activity on most days. Move more often! Include strength training in your routine too.
  • Manage your stress level with techniques such as meditation and deep breathing exercises.
  • Get at least 7 hours of quality sleep per night.
  • Check a fasting blood glucose level every six months.


There are no treatments that significantly slow or stop the progression of Alzheimer’s disease. The best hope is prevention and that starts with lifestyle habits. One of those is to prevent insulin resistance. While there are still many unanswered questions about how blood sugar affects our brains, understanding the link between these two things could lead to better ways of preventing dementia and other neurodegenerative diseases down the line.


  • “Insulin Resistance and Diabetes | CDC.” cdc.gov/diabetes/basics/insulin-resistance.html.
  • “Insulin Resistance | ADA – American Diabetes Association.” diabetes.org/healthy-living/medication-treatments/insulin-resistance.
  • “Insulin and Insulin Resistance — The Ultimate Guide.” 24 Jul. 2019, healthline.com/nutrition/insulin-and-insulin-resistance.
  • Cetinkalp S, Simsir IY, Ertek S. Insulin resistance in brain and possible therapeutic approaches. Curr Vasc Pharmacol. 2014;12(4):553-64. doi: 10.2174/1570161112999140206130426. PMID: 23627981.
  • Ferreira LSS, Fernandes CS, Vieira MNN, De Felice FG. Insulin Resistance in Alzheimer’s Disease. Front Neurosci. 2018 Nov 13;12:830. doi: 10.3389/fnins.2018.00830. PMID: 30542257; PMCID: PMC6277874.
  • “Study finds strong link between insulin resistance and dementia.” 29 Mar. 2017, belmarrahealth.com/study-finds-strong-link-insulin-resistance-dementia/.
  • “What’s the relationship between diabetes and dementia?.” 12 Jul. 2021, health.harvard.edu/blog/whats-the-relationship-between-diabetes-and-dementia-202107122546.

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