I have only anecdotal evidence on this question and in time I'm sure the hardcore research will catch up. Yes, I think that correcting methylation is a worthy pursuit in efforts to heal from pd. But you need to have a sophisticated knowledge of biochemistry to fine tune methylation pathways. The folks who have that knowledge plus the clinical expertise are docs who work under the rubric of functional medicine, integrative medicine or Bioindividualised medicine.

Rather than throwing b12 or SAMe or glutathione at the problem in a random fashion they first run functional tests to see how u are performing as a methylator, not just looking at serum levels. Then they know what precursors to introduce, when and where and how to avoid triggering feedback inhibition. They also investigate underlying causes. Leaky gut seems to be extremely common. Triggers for that are common allergens like gluten, dairy or soy.

Folks are very focused on gluten as an issue but I suggest that you consider parasites and fungal overgrowth equally as they are just as implicated in dysbiosis. My functional med doc says that 80 percent of stool samples she submits are coming back positive for parasites (including my own and an acquaintance with pd). The problem is there if you look for it. This creates two problems. Toxins getting thru and malnutrition. I have shown up some major nutritional deficiencies which are now being corrected. I am also being treated for fungal overgrowth in gut as well as parasite. There's a long road ahead. Parasites are not easy to eliminate.

One such doc I spoke to said that when you treat such underlying conditions in pwps, their symptoms either abate or vanish completely. Worth a try. Pd aside, we'd all benefit from cleaning up our gut.