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.
A vegetarian diet can be perfectly healthy; in fact, a vegetarian or vegan diet can improve digestion and skin tone, give you more energy and help you lose weight. But many vegetarians and vegans don't realize that their diets could be lacking in vital nutrients, vitamins and minerals. If you follow a vegetarian diet, you could be at risk of developing health problems including chronic fatigue, lowered immune response and even malnutrition.