Researchers at the National Institute on Aging have come up with another good reason to take your vitamins. A folic acid deficiency may increase the brain's susceptibility to Parkinson's disease, according to a study published in a recent issue of the Journal of Neurochemistry. Scientists administered a chemical that induces Parkinson'slike symptoms to mice and found that those with low amounts of dietary folic acid developed severe symptoms of Parkinson's disease while the mice with adequate folic acid in their diets exhibited only mild symptoms of the disease.