Blood Glucose & Your Brain

Two facts worth considering:

1. Your brain runs on glucose, and if there’s not enough, it won’t work well
2. Blood sugar levels are definitely something where it’s entirely possible to have too much of a good thing

This much is not too tricky to reconcile.

After all, your car might run on gasoline, but filling the tank to overflowing and dowsing your car in it will not improve its performance, to put it mildly.

So, when it comes to blood glucose and the brain, where does the danger zone lie? When does it stop being a “extra fuel” and start being “we dowsed it in fuel and now it’s a burning wreck”?

It’s about the big picture

Recently, researchers (Dr. Lina Jin et al.) analyzed neuroimaging, metabolomic, and genetic data from the UK Biobank and found that higher blood glucose levels were strongly associated with faster brain aging.

How much data is that, you ask?

The best-performing model was applied to 37,458 UK Biobank participants to calculate the brain age gap (BAG), which measures how much older or younger a person’s brain is (according to epigenetic clocks) compared with their chronological age:

❝Using 1,079 imaging-derived phenotypes (IDPs) from 4,333 healthy participants, we trained and validated machine learning models for brain age prediction, with a least absolute shrinkage and selection operator (LASSO) regression model achieving the best performance (mean absolute error = 3.26 years, R² = 0.68). Brain age gap (BAG) was then estimated in 37,458 participants. Association analyses in 21,780 individuals identified nine plasma metabolites significantly linked to BAG after Bonferroni correction, with glucose showing the strongest effect (β = 0.32, P = 9.90 × 10⁻¹²).❞

And as for how much this matters: the brain usually shrinks after your 30s or 40s, but accelerated brain aging is linked to earlier memory loss, cognitive decline, and a higher risk of neurological, psychiatric, and neurodegenerative disorders.

In fewer words: higher blood glucose levels were associated with an increased risk of all-cause dementia, Alzheimer’s disease, vascular dementia, Parkinson’s disease, stroke, depression, and anxiety.

And in particular, higher glucose concentrations were linked to poorer cognitive performance, reduced movement function, and worse mental health outcomes.

Structurally, the study saw consistent results too: elevated blood glucose was associated with smaller brain volumes across 80 cortical, subcortical, and cerebellar regions, indicating widespread structural changes rather than effects confined to a few brain areas. That’s a lot, and there are not many worse things you can do in this regard (if you do want ideas for doing worse, though, options include Don’t Shrink Your Brain With This Habit and How Does Alcohol Cause Blackouts?).

The effects of chronically elevated blood sugar levels are thus also quite related to what we talked about in: The Surprising Place Fat Can Accumulate To Shrink Your Brain ← since that also pertained, ultimately, to metabolic mishaps.

As for what all this means in practical terms: all these findings strongly suggest (do not outright prove, because the study was associative, but it seems very clear) that glucose metabolism can be a modifiable pathway influencing brain aging, reinforcing the idea that maintaining healthy blood glucose levels can help preserve brain health and reduce the risk of age-related brain disorders.

If you’d like to read the paper in full for yourself, here it is: Metabolomic signatures of brain aging: A multimodal and genetic study

Want to learn more?

To learn more about how to most easily and effectively manage your blood sugar levels, do swing by these previous main features of ours:

• Improve Your Insulin Sensitivity!
• 10 Ways To Balance Blood Sugars
• Eating For Energy (In Ways That Actually Work)
• Glycemic Index vs Glycemic Load vs Insulin Index
• Which Sugars Are Healthier, And Which Are Just The Same?

And to learn much more deeply about this, check out this excellent book that we reviewed:

Why We Get Sick – by Dr. Benjamin Bikman ← this is about insulin resistance, and, importantly, the invisible insulin resistance that precedes blood sugar imbalances by many years (it goes unnoticed because the pancreas will dutifully keep cranking out more and more insulin to keep the blood sugars stable, until one day it just can’t keep up anymore, and then and only then does prediabetes get diagnosed).

Take care!