I think someone found a disproportionate number of Parkinson's patients , who tested positive for the HP bacteria and there have been suggestions that the gut plays a role in the disease (as well as the brain)
Any slight abnormality that is found to be prevalent among us is of interest as we are so keen to find a cure and the normal route of research is too slow for us, we would like someone to stumble upon the causative agent out of the blue, with readymade treatment included, of course. And we all try to find what caused our own PD version.
The difficulty of the tests (of any research into PD for that matter) you are suggesting are that A. the sample of patients taking part is very small, B, PD is a disease of many different aspects (might be more than one disease), C. It is a disease that is particularly sensitive to the placebo effect, D.progress is very variable, some are still without drugs after 8-10 years without having followed your or chewexperts dietary advice. I was diagnosed almost 15 years ago and have seen a lot of trials come and go where the final conclusions only came up negative.. A lot of money has gone into research over the last 50 years. (this site is run by the biggest contributor to research into PD in the UK )
I am sure looking after your general health is beneficial. Good luck, I wish you a lot of patience and persistence.