Nerve damage begins before glucose reaches diabetic range. This is the most important thing patients are not told. That is because it is the window when the damage can still be reversed.
Why “your sugar is fine” is not the same as “your nerves are fine”
The cutoffs for diagnosing diabetes were set by the risk of eye and kidney disease. They were not drawn around nerves. Small nerve fibers appear to be damaged at blood sugar levels below those lines.
So a patient with an A1c of 5.9 and burning feet is told again and again that their sugar is normal. It is normal by a cutoff built for a different problem. The nerves are reporting something the number was never built to catch.
What that means in practice
- Small-fiber symptoms come first: burning, tingling, night pain and skin that is too sensitive. They arrive years before numbness.
- Standard nerve conduction testing is often normal, because it measures large fibers. A normal test does not rule this out.
- This is the reversible stage. Small fibers grow back. Once large-fiber loss has set in, the conversation changes.
Both points are covered in more detail under small fiber neuropathy and can diabetic neuropathy be reversed.
What we actually look at
A fasting glucose and an A1c are averages and cutoffs. Neither shows what happens to you after a meal. That is where the damage is being done.
Post-meal glucose and glucose variability are the numbers that tell you something. Continuous glucose monitoring is how you see them. Two people with the same A1c can have totally different spikes. It is the spikes that track with nerve injury.
What changes the trajectory
The evidence for acting at this stage is better than at any later stage. None of it is exotic. Lose weight when that applies. Change the shape of the blood sugar curve, not just its average. Address insulin resistance head on. And correct the other things quietly adding to the injury: B12, thyroid and alcohol. See metabolic care.
The step worth adding is measurement. Advice based on an A1c every three months is advice given blind. Advice based on a two-week continuous glucose trace is specific: this meal, this time of day, this pattern.
Why this matters more than the label
Patients often get stuck on whether they meet the bar for diabetes. Here it barely matters. The nerves do not know where the cutoff is. Waiting to cross it before acting means waiting until part of the damage can no longer be undone.
Do you have burning or tingling feet, and were you told your sugar is borderline? That combination is worth investigating properly, not just watching. See also burning feet at night.
To get checked, call or text us. We are at 12174 Natural Bridge Rd, Suite 110, St. Louis, MO 63044.
Common questions
My A1c is 5.8. Can that cause neuropathy?
Yes, it can be associated with small-fiber damage, especially when post-meal spikes are large. The cutoff for diabetes was not drawn around nerve risk.
My nerve test was normal. Does that settle it?
No. Standard nerve conduction studies measure large fibers. Early diabetic nerve damage hits small fibers. It can be there even with a normal test.
Is it reversible at this stage?
This is the stage where recovery is truly realistic, because small fibers grow back. That is the case for acting now instead of waiting.
Can Diabetic Neuropathy Be Reversed? goes through it in detail.
Do I need continuous glucose monitoring?
It is the most useful single test at this stage, because it shows the swings and post-meal spikes that an A1c averages away.
Which supplements are worth taking, and the one to stop.
Sources
- Ziegler D et al. Neuropathy in prediabetes. Diabetes/metabolism research and reviews, 2023. PubMed 37470302
- Stino AM et al. Peripheral neuropathy in prediabetes and the metabolic syndrome. Journal of diabetes investigation, 2017. PubMed 28267267
- Thaisetthawatkul P et al. Prediabetes, diabetes, metabolic syndrome, and small fiber neuropathy. Muscle & nerve, 2020. PubMed 32012301
- Elafros MA et al. Towards prevention of diabetic peripheral neuropathy: clinical presentation, pathogenesis, and new treatments. The Lancet. Neurology, 2022. PubMed 36115364
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