The blood sugar and brain ledger

I ran a school cafeteria in Fresno for twenty years. I know what 600 kids eat for lunch, I know what a sheet cake costs per slice, and I know that numbers do not lie as easily as people do. At 55 my doctor told me my A1c was 6.1. That put me in the prediabetes range, and it made me start reading.

What I did not expect was how much of that reading would be about the brain.

Why blood sugar and memory ended up on the same page

The link is not a theory somebody made up to sell supplements. People with diabetes have a higher risk of dementia. A 2024 analysis that pooled 15 studies with more than ten million people put the increase at about 59% (Cao, 2024). The same analysis found that episodes of very low blood sugar also raised the risk, which matters for anyone on diabetes medication.

How it happens is still being studied. High blood sugar damages small blood vessels, including the ones in the brain. Insulin also does work in the brain beyond moving sugar around, and when the body stops responding well to insulin, the brain may be affected too. The NIDDK page on insulin resistance and prediabetes explains the body side of this clearly.

What this ledger is

I keep notes the way I kept inventory: columns, numbers and sources. Three entries so far:

The numbers: what A1c and fasting glucose results mean, and what the research says about each range and the brain.
The supplements: berberine, cinnamon, banaba leaf, olive leaf and kudzu flower, side by side, with the doses that were actually studied.
The cautions: what happens when you stack blood sugar supplements on top of diabetes medication, and the questions I took to my pharmacist.

Why supplements are in here at all

Because they are everywhere now. A few years ago blood sugar supplements and memory supplements were sold separately. Now many memory products are built around blood sugar ingredients, with ads that talk about "type 3 diabetes." If you have seen those ads and wondered whether it is real, there is a good explainer on type 3 diabetes, explained without the hype that matches what I found in the research: a serious scientific idea, not an official diagnosis.

My own rules

I am not a doctor, and my care plan comes from mine. But here are the rules I set for myself after a year of reading:

Food and walking first. The American Diabetes Association's page on diagnosis is clear that prediabetes can often be turned around with lifestyle changes, and mine came down to 5.8 in a year.
Get the A1c checked at least once a year, more often if it is climbing.
No supplement goes in my cabinet until my pharmacist has seen the label.
If a product does not list milligrams, I treat its claims with a grain of salt. Not literally. I am watching my sodium too.

Everything in this ledger has a source next to it. If you find a number that is wrong, tell me. In a cafeteria, if the count was off, you recounted. Same here.

Diabetes Medication and Memory Supplements: What to Check FirstTaking metformin or insulin and thinking about a memory supplement? Signs of low blood sugar, drug interactions to ask about, and a simple home testing plan.Berberine, Cinnamon, Banaba, Olive Leaf: A Blood Sugar LedgerFive blood sugar supplement ingredients side by side: the doses studied, trial sizes, what changed, and the caution that comes with each one.Prediabetes Numbers and the Brain: A1c, Fasting Glucose, MemoryA1c and fasting glucose ranges explained, what the research links to memory at each level, why low blood sugar matters too, and the tests worth asking for.

Rosa Delgado managed a school cafeteria in Fresno for twenty years and learned she had prediabetes at 55. She keeps this ledger of what the research says about blood sugar and the brain. She is not a doctor; her own care plan comes from hers.