Don't forget that curcumin (tumeric) closes the blood/brain barrier, whilst stress opens it. Parkies have been shown to have a defective blood/brain barrier, which allows toxins into the brain. These toxins circulate harmlesly in the blodsream of a normal person.
Ron
Blood-brain barrier dysfunction in Parkinson’s disease
KL Leenders, R Kortekaas, AL Bartels, J Oostrom, A Willemsen, J Bart
S77, P257

The blood-brain barrier is defective in PD patients, according to this study. PET imaging of verapamil was used to measure activity of the P-glycoprotein system, which transports unwanted substances out of the endothelium back into the blood. Comparing five PD patients to five controls, the authors found significant differences in the brain penetration of verapamil (18% higher for PD patients, p=0.02) only in the midbrain region. All patient values were higher than all controls. The authors suggest, “A faulty BBB function on the basis of genetic predisposition might in the course of years allow toxic compounds—or compounds normally circulating in the blood but not passing the BBB—to enter the brain in certain regions and damage vulnerable cells.”