Are certain foods better for people with Parkinson disease (PD)? Are others harmful?
A recent review article explores the idea that eating some foods and avoiding others could be a nutrient prescription for Parkinson disease.1
More and more studies are pointing toward the benefits—and risks—of certain foods in PD. Specifically, some nutrients may decrease the risk of PD or delay its progression. Some investigations show that high intake of fruits and vegetables slows disease progression. Because plant nutrition is rich in anti-oxidants, fruits and vegetables may stave off the high oxidation found in people with PD. Levels of naturally occurring anti-oxidants, including glutathione, are low in the brains of people with PD.
In an interview about the recently published study, The Emerging Role of Nutrition in Parkinson’s Disease,1 author Dr. Potashkin noted, “nutrient-rich vegetables and fruits not only supply much needed fiber to prevent constipation, they also supply fluid to help keep the patient hydrated. In addition, they supply essential polyphenols to help maintain the overall health of the patient.”
Polyphenols are a type of anti-oxidant. Other anti-oxidants supplied by fruits and vegetables with potential benefit in PD include carotenoids, lycopene, riboflavin sulforaphane, and erucin. Nicotine-containing vegetables, such as tomatoes, potatoes, and peppers could also help, potentially due to the nicotine content and effects on the acetylcholine system, or due to anti-oxidant effects of other nutrients found in the vegetables.
Many recent articles have also pointed toward the healthy benefits of omega-3 polyunsaturated fatty acids (PUFAs). These nutrients include: alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid. Although no specific study has examined the effect of omega-3 fatty acids in people with PD, there have been several investigations showing that these PUFAs help promote neuronal health. A recent rat study showed that when the animals ate insufficient omega-3 fatty acids for 2 years, this caused degeneration of dopamine-producing cells in the substantia nigra2—exactly what happens in PD. More studies in humans are needed however, to establish a clear link between omega-3 fatty acid deficiencies and PD.
Dairy products seem to increase the risk of PD, especially in men. There may be a link between milk consumption which, in some studies, has been shown to decrease plasma uric acid levels. High uric acid levels may correspond with lower PD risk, but this effect is apparently limited to men. It is possible that dopamine neuron toxins are present in dairy products, including pesticides. The dairy effect is specific to milk: researchers have not found a similar association between other dairy products, such as cheese and yogurt. The milk-Parkinson’s disease theory must be viewed with some caution, since some studies point toward this association, but other studies show no milk-Parkinson’s disease link.1
Despite several studies indicating that specific food groups may have an influence on PD symptoms, more research is needed to establish strong links. Dr. Potashkin cautions “The total elimination of any one food group lacks sufficient scientific evidence at this time.”
Dr. Potashkin described several studies in progress and the current need for more, stating “There are several clinical trials currently testing caffeine, green tea, ketogenic diets, and vitamin D, among others, in Parkinson disease. We need more large prospective randomized controlled studies designed to test whether a well-balanced diet of nutrient-rich foods, including vegetables and fruits and moderate amounts of omega-3 fatty acids, tea, caffeine, and wine may slow the progression of PD.”