So if you Google "vegetarian risk Parkinson's" you will be flooded with articles saying that vegetarian is best for PD and that PD risk is lower for vegetarians. I am not disputing this.
But... I was reading this very short paper: sci-hub.st/10.1016/S0016-50...
Dietary Lectins As the Environmental "Unknown Pathogen" in Parkinson's Disease
"Luca Toti, Gregory M. Holmes, R. Alberto Travagli
In the search for environmental clues that might trigger the development of Parkinsons' disease (PD), Braak's group observed the early onset of gastrointestinal (GI) symptoms in PD patients and hypothesized that an "unknown pathogen" penetrates the GI walls and enters the central nervous system via retrograde transport through the vagus nerve, ultimately reaching nigrostriatal dopaminergic neurons to induce their degeneration. Dietary plants, in general, are rich in glycoprotein-lectins which can penetrate the wall of GI tract by endocytosis or via a lectin receptor (saccharide)-mediated mechanism. Lectins, by virtue of their permeability, could act as a chaperon for viruses and toxin(s). Moreover, a vegetarian diet that comprises plant lectins is related to a greater incidence of PD compared to a diet dominated by meat consumption. We aimed to test whether dietary lectins are the environmental clues that might trigger the development of GI impairments that are observed in the early phases of PD. Sprague-Dawley rats of either sex were gavaged daily for 5 consecutive days with fluorescent conjugated lectins from Pisum Sativum (0.1% in 150μl of PBS).
To maximize contact time and absorption, CCK (3μg/kg/ip) was injected 15min prior to the gavage to reduce gastric emptying. Control rats received a PBS solution with 0.1% lectin-free retrograde tracer. Gastric emptying was assessed, starting 7 days prior to the first gavage (baseline), using the non-invasive [13C]-octanoic acid breath test. 10-13 weeks after the treatment, the rats were anaesthetized, gastric motility and tone were recorded with strain gauges applied to the corpus surface. Tyramine (270pmoles/60nl), thyrotropin releasing hormone (TRH; 100pmoles) at the level of the dorsal vagal complex (DVC) or NMDA (5.25nmoles) at the level of the substantia nigra pars compacta or bethanechol (50μg/
kg/iv) were injected. At the conclusion of the experiment, animals were fixed for brainstem immunohistochemistry (IHC) After 13 weeks animals gavaged with a solution of lectin 0.1% (N=6) show a significant decrease in gastric emptying compared to control animals (N=4).
The gastric motility and tone results are summarized below. IHC staining shows that in lectin-conjugated treated animals, but not in control animals, labeling is present in both TH-IR +ve and TH-IR -ve DVC neurons (n=2). Our data indicate that dietary lectins induce gastric impairment that could be caused by their transport into GI-projecting brainstem areas, mimicking the early stages of the PD as hypothesized by Braak's group. Supported by: NIH DK55530"
It has this line: Moreover, a vegetarian diet that comprises plant lectins is related to a greater incidence of PD compared to a diet dominated by meat consumption.
I am trying to get more information on this.