When you hear the word Alzheimer’s, your first thought probably isn’t blood sugar. But what if it should be? More and more researchers are starting to call Alzheimer’s “Type 3 diabetes” — and while the medical community isn’t officially changing the name just yet, the idea is worth exploring.
Why? Because this way of thinking doesn’t just give Alzheimer’s a new label. It changes how we understand what’s happening in the brain — and maybe, just maybe, how we can prevent or slow it down.
The Brain–Blood Sugar Connection
We’ve long known there’s a strong link between type 2 diabetes and Alzheimer’s. People with diabetes have higher rates of cognitive decline, and the mechanisms overlap:
Oxidative stress & inflammation (think internal rust and fire)
Protein damage and nerve cell death
Genetics that may predispose people to both
For years, scientists thought the brain wasn’t particularly sensitive to insulin. Turns out — it is. Your brain cells actually have insulin receptors, and they use insulin to:
Build and maintain connections (a.k.a. synapses, where memories form)
Help neurons survive stress
Support learning and memory
So if insulin isn’t working properly in the brain, the whole system starts to falter. This may help explain why we see hallmark Alzheimer’s changes like amyloid plaques, tau tangles, and memory loss.
What the Genes Are Saying
A 2025 study found that certain genes in charge of glycolysis (that’s how your brain cells turn glucose into usable energy) were dialed down in people with Alzheimer’s. The worse the gene activity, the more tau tangles showed up.
Translation? The brain is literally struggling to turn fuel into energy — which could accelerate the damage.
Do Diabetes Meds Protect the Brain?
Here’s where things get really interesting:
Metformin (a common diabetes drug) seems to calm inflammation, fight oxidative stress, and even shore up the blood-brain barrier.
Semaglutide (a GLP-1 agonist you may have heard of for diabetes and weight loss) was linked to a significantly lower risk of Alzheimer’s in one big population study.
Now, researchers don’t know if these drugs should (or could safely) be used in people who don’t have diabetes but are at risk for Alzheimer’s. But the evidence is promising.
So… Is Alzheimer’s Type 3 Diabetes?
Not quite. Plenty of people with Alzheimer’s have never had diabetes. And the disease is almost certainly multifactorial — meaning it’s caused by a messy mix of factors like genetics, nutrition, stress, and overall health.
But thinking of Alzheimer’s as “Type 3 diabetes” does one powerful thing: it gives us a new way to intervene earlier. Instead of only focusing on removing plaques once they’re already there, maybe we can work on preventing the metabolic dysfunction that sets the stage.
What This Means for You
Even though researchers are still working out the details, the takeaway is crystal clear:
Protect your blood sugar, protect your brain.
Prioritize balanced meals with protein, healthy fats, and fiber.
Move your body daily — exercise makes your brain more insulin-sensitive.
Sleep and stress management matter just as much as diet.
Your brain runs on fuel. If the fuel system is glitchy, the engine sputters. But with small, consistent lifestyle changes, you can keep those neurons firing on all cylinders for years to come.
Bottom line: Whether we end up calling it Alzheimer’s or “Type 3 diabetes,” the message is the same — caring for your metabolism is one of the best long-term investments in your brain health.
If this article sparked questions or if you’d like more personalized tips, I’d love to hear from you.
Hi Alison – It truly is amazing how everything, oftentimes, comes down to just a few things that we can do to make life easier and more manageable. It is not that things are simple, but if we take care of ourselves early on, we may be able to prevent situations that are difficult. I understand we can’t prevent everything, but we can certainly make it easier. As I get older, I am finding the value and importance in diet, exercise and movement. I am also finding the value in my mental clarity as I focus on a positive mindset. Do you recommend any natural supplements in addition to prescribed medication? I don’t have this condition and certainly hope I never will, but as a preventative measure, I’m wondering what I can do right now to offset any symptoms or simply be healthier. Thank you for educating us with your blog posts on these important topics!
Hi Alison,
Timing of your post couldn’t be more personal for me. My annual check-up with my family physician was quite à-propos: my sugar levels are too high and he inclined for me to start taking type-2 diabetes pills to lower them.
I’m in shape, work out 3X a week. My food intake is pretty darn good – no fast-food, etc… but like he said, it might be hereditary as well.
So, we’re going to meet up with a dietician and see how I can help my body stay in great shape. Late 50’s sure wasn’t planned like this! Thanks for the reminder to take care of our temple!