You have to careful when you eat protein if you take Carbidopda/ Levidopa. Protein interferes with the proper absorption of that medication. You should eat it at least 1/2 hour before and one hour after. Some guidelines call for double that.
Parkinson’s can also cause constipation and if this is the case for you, you should eat easily digestible food. If it’s bad enough you should put your food into a food processor.
I don’t know of any supplements you can’t take. Some people with Parkinson’s can’t retain vitamins B12 and D3 from food and need to take those supplements. There are a lot of supplements that are commonly taken by PWP’s. Calcium and magnesium for leg cramps. Melatonin for sleep. CBD or Cannabis for pain, and many more that I can’t currently remember.
The Q & A section has a search function where you can read previous questions and answers. There’s a ton of useful information available there.
Meant to add....but it can cause loose BMs which can be a problem.
I agree with Dale's response above. Magnesium can help with constipation as well. After all, mag sulfate is used as a colonoscopy prep.