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 recent study indicated that the average vegan diet is higher in vitamin C and fibre, and lower in saturated fat than one containing meat. In addition, statistics show that vegans have a lower BMI (height-to-weight ratio) than meat eaters â in other words, they are skinnier.