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.
Like a plant-based diet, a vegan diet excludes animal-derived foods, but also involves a moral aspect. In addition to dietary choices, many vegans adjust their lifestyle by avoiding non-food products like clothing and makeup containing animal-derived materials. In fact, many say thereâs no such thing as a vegan diet.