I like your out of the box thinking and willingness to look at PD from multiple perspectives. I know acetaldehyde is a toxic byproduct of having candidiasis, usually in the gut. But i believe if one has an overgrowth of candida that it is the result usually of antibiotic usage. I think in terms of gut dysbiosis, where there is a disruption in the balance of friendly virsus pathogenic bacteria. Once this balance has shifted toward favoring a predominance of pathogenic organisms, we are in trouble. There is good evidence to suggest the efficasy of human probiotic infusion to improve the health of the human microbiome. The gut and the brain are connected.