A review of the primary nutritional and environmental factors associated with Parkinson’s disease

Parkinson’s disease is a progressive nervous system disorder that produces both motor and nonmotor symptoms. This literature review begins by examining evidence for several possible origins for the disease:  does it begin in the brain and progress to the gut, or vice versa, or does it begin in both places concurrently?  Next, we examine several environmental factors that have been shown to either increase or decrease risk of Parkinson’s disease. These are primarily nutritional factors, specifically caffeine, nicotine, and dairy products. Studies in both animals and humans provide weak evidence that increased consumption of low fat dairy is associated with an increased risk of Parkinson’s disease development. Additionally, there is strong evidence that nicotine has a neuroprotective effect which also lowers the risk.  Finally, there is similarly strong evidence that caffeine exerts neuroprotective effects which lower the overall risk of developing Parkinson’s disease.