The big catch is that vegan diets seem to be protective against the progression of Parkinson’s disease: https://pubmed.ncbi.nlm.nih.gov/11516224/
As is often the case, the truth is probably a lot more nuanced than “x causes y”.
As is often the case, the truth is probably a lot more nuanced than “x causes y”.
> Three recent case-control studies conclude that diets high in animal fat or cholesterol are associated with a substantial increase in risk for Parkinson's disease (PD); in contrast, fat of plant origin does not appear to increase risk.
> In aggregate, these findings suggest that vegan diets may be notably protective with respect to PD. However, they offer no insight into whether saturated fat, compounds associated with animal fat, animal protein, or the integrated impact of the components of animal products mediates the risk associated with animal fat consumption.
That is, the underlying cause could very well just be high cholesterol, and that the carnivores in the study were more likely to have high cholesterol than the vegan groups, either due to lifestyle choices (despite veganism itself not implying any sort of healthy lifestyle, there might be a stronger overlap with those choosing veganism and those leading a healthy lifestyle than for carnivores), or due to difference in dietary cholesterol intake.
Later: "Surprisingly, tobacco smoking is also markedly protective with respect to PD"
In general, the conclusions of it are weak because it's a very weak paper. These vegan diets were compared against what? I can't be bothered to follow all sources, but this paper doesn't seem to pose this question either, which is a noticeable omission which smells of agenda.
Are they comparing against people eating random junk like most of the Western world? Then of course any diet eliminating of our ultra-processed food is healthier, be it vegan, pescatarian, ketogenic, paleo, carnivore, Mediterranean, etc.