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Brain Health 101: How Insulin Resistance Affects You and What to Do About It
- Shannon Kasun
- Jan 13
- 3 min read
Updated: Feb 19
By Shannon Kasun, CerePro Neuroscience Specialist
I grew up next to a train station. The ear-shattering whistle of an approaching or departing train quickly became a familiar background noise. Over time, it no longer woke me up at night, disrupted my focus on homework, or distracted me during phone calls. Nothing about the train changed—it still screeched as its brakes clamped the rusted tracks—but I changed. I stopped reacting to it.
This phenomenon mirrors what happens during insulin resistance. Insulin, a hormone released by the pancreas, helps move glucose (sugar) from the bloodstream into cells, where it’s used for energy. When you consistently consume foods with a high glycemic index—like white bread, white rice, and baked goods—your pancreas is forced to produce excessive amounts of insulin to regulate your blood sugar levels.
Eventually, these elevated insulin levels become a constant presence, much like the train whistle from my childhood. Overexposure leads your cells to stop responding to insulin— the way I no longer react to the train—a state known as “insulin resistance.”
Why Is Insulin Resistance Bad for Your Brain?
Insulin resistance can severely impair brain function. When brain cells (neurons) fail to respond to insulin, glucose cannot enter the cells, leading to energy deficits that disrupt their function. This condition may harm neuroplasticity—the molecular foundation of learning and memory—as well as impair neurotransmission, receptor regulation, metabolism, cognition, and mood (Arnold et al., 2018).
Under normal conditions, insulin supports neuron survival. It binds to receptors on neurons, triggering a cascade of signals that prevent apoptosis (programmed cell death) and preserve neuronal health (van der Heide et al., 2006). However, chronic insulin resistance undermines these protective effects.
After insulin performs its role, it is broken down by insulin-degrading enzyme (IDE), which also degrades amyloid-beta, a protein associated with Alzheimer’s disease. When insulin levels are persistently elevated, IDE becomes overwhelmed, leaving amyloid-beta to accumulate, potentially contributing to Alzheimer’s.
These consequences of insulin resistance can contribute to neurodegeneration and cognitive decline, as seen in Alzheimer’s disease. In fact, some researchers refer to Alzheimer’s as “Type 3 diabetes” due to its strong link with insulin resistance.
How to Prevent Insulin Resistance and Support Brain Health
A healthy diet is a powerful tool for preventing insulin resistance and promoting brain health. Here’s how to get started:
Limit Sugar Intake: The human body is not designed to process more than 15 grams of sugar per day (Bredesen, 2020). For context, a Starbucks Caramel Frappuccino contains about 60 grams of sugar—four times the recommended amount.
Focus on Low Glycemic Foods: Incorporate foods with a glycemic index below 35 into your meals. Harvard Medical School offers a comprehensive list of glycemic indices for common foods: Glycemic Index List
Elevate Veggies: Make vegetables the star of your plate, not just a side dish. Opt for raw or lightly cooked vegetables to preserve nutrients and avoid glycotoxins created by grilling or frying. A personal favorite is Israeli salad, made with diced cucumbers, tomatoes, onions, lemon juice, and olive oil—delicious and detoxifying!
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