GCG and Parkinson disease: In the end, VSL#3 supplementation activates GLP-1, and alleviates fatty liver and body mass index (NCT01650025).330 Multistrain probiotics treatment including Bifidobacterium bifidum, Bifidobacterium longum, Enterococcus faecalis, Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus gasseri, Lactobacillus reuteri, and Lactobacillus rhamnosus displays effective for the treatment of constipation in PD (NCT03377322).32 Besides, leptin as a probiotic substance affects gut microbiota and vagus nerve, which plays an important role in liver and brain function.