Parkinson's disease (PD) is a type of movement disorder. It happens when nerve cells in the brain don't produce enough of a brain chemical called dopamine. Sometimes it is genetic, but most cases do not seem to run in families. Exposure to chemicals in the environment might play a role.
Why Vegans are Often Deficient in Vitamin B12. The few plant foods that are sources of B12 are actually B12 analogs. An analog is a substance that blocks the uptake of true B12, so your body's need for the nutrient actually increases.
The basics of a vegan diet. As a vegan youâll be avoiding all animal-derived foods â so as well as meat and fish that means no eggs, dairy or even foods like honey. Youâll also be avoiding animal by-products like rennet used in cheese making, gelatine in desserts and certain E numbers including the red food dye cochineal (E120).