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.
These vegan-like diets eliminate all animal products, including meat, poultry, fish, eggs, dairy and honey. Everything you eat â including whole grains, fruits, vegetables, legumes, nuts and seeds â is derived from plants. Research reflects that following a plant-based diet has health benefits, if you do it correctly. A plant-based diet is also more likely to result in weight loss than a vegan diet.