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.
There is no need to eat fatty, sugary, and refined packaged foods, nor fish, meat, eggs, and dairy products. A vegan diet, supplemented with vitamin B 12, helps keep you slim and resistant to illness while providing all the nutrients necessary for optimal health.