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.
What Do Vegans Eat? Veganism is a type of vegetarian diet that excludes meat, eggs, dairy products and all other animal-derived ingredients. Many vegans also do not eat foods that are processed using animal products, such as refined white sugar and some wines.