More studies are showing that contrary to popular, advertising-influenced beliefs, neither milk nor meat ‘does a body good’. A 2001 study concluded that meat/dairy-based diets substantially increase the risk of Parkinson’s disease. The problem is the animal fat and cholesterol associated with these diets. Parkinson’s disease is a phenomena mostly experienced by Americans and Europeans: population groups consuming large quantities of meat and dairy. People groups whose diets are more plant-based (Chinese, Japanese, Sub-Saharan African, etc.) have much lower rates of this disease. Because a vegan diet is not artery clogging and is more nutritive, it provides more protection for the brain, thereby maintaining its integrity despite advanced age.

McCarty MF. Does a vegan diet reduce risk for Parkinson’s disease? Med Hypotheses. 2001 Sep;57(3):318-23. PubMed PMID: 11516224.