Isekai Yakkyoku - Vol. 14 Ch. 70 - Parkinson's Disease

[Defeqel]

This is also going up against the limits of modern knowledge. Depending on when this was written, we've only "recently" discovered that drugs that remove the similar plaques involved with Alzheimer's, doesn't necessarily help the patient. Google Donanemab, and the controversy about their approval in 2024. Patient groups and Alzheimer's groups clamored for it, the science behind it was pretty bad, so the actual Science people said it's not worth it as a drug. Patient groups won out, for an incredibly expensive drug that has horrid side effects and doesn't have many benefits. The other "new" drug, Lecanemab also is pretty ineffective overall. I'd guess the author may have known about some of the clinical studies, but not the results when this was originally written. So they may not want to jump the gun on unproven therapies. Even if you use magic.

Not to mention we've had studies about a subset of people whose one branch of the vagus nerve (IIRC) was cut and it drastically reduced the chances of developing Parkinson's. There has also been studies about lectins (toxins) traveling via nerves. So at least one cause of Parkinson's seems to be leaky gut which allows those lectins in. We also have studies where a keto diet improves the symptoms, but it is difficult to assess whether it is due to lessening the effects of Parkinson's itself, or improvements to general brain health, improvements to gut health, or something else.

It is always a risk with stories like these: the science "changes" over time, which then also ages the story that so heavily relies on it.