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.
Vegetarians Lack. Both vegetarian and non-vegetarian diets have advantages. Both vegetarian and non-vegetarian diets have advantages. Vegetarian diets tend to be rich in antioxidants, certain vitamins, and healthy fats. Non-vegetarian diets, by contrast, tend to contain more protein, iron, zinc, calcium, and vitamin B-12.