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.
Although these diets seem similar, they are not the same. A plant-based diet emphasizes vegetables, grains, legumes and fruit, nuts and seeds, spices, with little or no animal products. A vegan diet is a plant-based diet with no food from animal sources. The term veganism can also refer to a lifestyle that rejects the use of animal products for any reason.