A book entitled "Excitotoxins: The Taste that Kills" by Russell L. Blaylock, M.D. will answer that question for you. He is a neurosurgeon also involved in research so he has done repeated animal experiments. So I rarely have aspartame now. It did give me headaches, which is a result of the effect it is having by over stimulating the brain which can cause tangles. He said anyone who has Alzheimer's disease in the family should stay away, so I did for that reason too besides the headaches.

My opinion, is based on a LOT of my own research on the Internet and books, since I cured my own in 2003. Sure, it is true that blood sugar levels do make the pain worse, but they do not cause it. But B vitamin deficiencies can bring it on and many drugs, especially the fluoroquinolone class of antibiotics, but the effect will not happen to absolutely everyone, but very often will in someone who is B vitamin depleted, like a person on metformin or a person who drinks, or in my case where a hospital flooded me with 40 lbs of liquid in three days and I got a kidney infection as a result of their poor treatment. So the Cipro was required and I got neuropathy within 8 of the 10 days I was supposed to take it, but I stopped early once I found on the Internet that others had been caused the same problem of neuropathy after Cipro. I've helped someone else who got worse after Avelox. Levaquin can also cause the problem. So even if you have excellent blood sugar control, you can get neuropathy for the damage caused by killing off friendly bacteria which is needed to absorb B6 through the intestines. The solution is very complicated, but I did it through supplements. It is easy to break an egg, but harder to put it back together and doctors just don't bother, so the standard treatment is medications to change the perception of pain. It annoys me a LOT that no one wants to take the longer route, but the people themselves care. It's the doctors who can't be bothered. Sometimes it happens after surgery. Also during surgery often antibiotics are used in a precautionary way hoping to ward off an infection. Someone I helped had got neuropathy both due to Cipro and also as it was used as a prophylactic around a surgical procedure. So it is not as likely to be caused by high sugars, IMHO as it is the drugs that people with diabetes are put on, but doctors would rather blame it on uncontrolled sugars than be told a drug could cause it, as that implicates them.