Mischley LK, Lau RC, Bennett RD. Role of diet and nutritional supplements in Parkinson’s disease progression. Oxid Med Cell Longev. 2017;2017:6405278.
This study was a cross-sectional analysis of an online platform created by the author (Laurie Mischley, ND, PhD). The platform enrolls Parkinson’s patients in a longitudinal research study. The patients self-report their Parkinson’s symptoms, diet diary, and supplement intake.
The study population included 1,053 people with idiopathic Parkinson’s disease; 93% of the participants were Caucasian, with an average of 5.2 years since diagnosis.
Study Parameters Assessed
Parkinson’s symptoms, progression severity, diet (by recall), and supplement intake; symptoms were assessed using the patient-reported outcomes in Parkinson’s disease (PRO-PD) scale, an outcome tool created by the author.
Primary Outcome Measures
The analysis compared each patient’s rate of disease progression to their diet and supplement intake to search for any statistically significant associations.
The results below show which foods and supplements were significantly (P<0.05) associated with a slowed progression or a more rapid progression of Parkinsonian symptoms.
|DELAYED PROGRESSION||MORE RAPID PROGRESSION|
|Fresh fruits and vegetables||Canned fruits and vegetables|
|Nuts and seeds||Diet and non-diet soda|
|Non-fried fish||Fried foods|
|Fresh herbs and spices||Cheese|
Parkinson’s disease is an extremely debilitating condition and is poorly understood.1 Conventional options are limited, and studies suggest that many Parkinson’s patients turn towards diet, natural medicine, and supplements to slow disease progression.2 However, little is known about their efficacy. The present study is an effort to shed light on the effects of diet and supplement use on Parkinson’s disease progression.
Many of the findings of this study are not too surprising. Most of the dietary items associated with delayed progression are elements of a Mediterranean-style diet. This style of eating is anti-inflammatory and has been shown to be associated with fewer cases and later onset of Parkinson’s disease.3 Fish oil has been shown repeatedly to be neuroprotective4 and indeed this study found an association between fish intake and a delayed progression of Parkinsonian symptoms.
Most of the dietary items associated with delayed progression are elements of a Mediterranean-style diet.
The association of consumption of canned foods with a more rapid progression of Parkinson’s disease is intriguing. Because this association persisted after adjustment for income it is less likely to be related to diminished access to health care (which often accompanies low income status). Could there be something in the cans themselves? The authors postulate that bisphenol A (BPA) or aluminum, a known neurotoxin,5 might be contributory.
The association of soda consumption with more rapid progression of disease may be due to specific neurotoxicants, such as aspartame.6 The association with fried foods may be related to lipid peroxidation. The association of ice cream, yogurt, and cheese with rapid progression is consistent with prior research; a meta-analysis of dairy intake and Parkinson’s disease showed an association of dairy intake with Parkinson’s in a dose-dependent manner.7 Both iron supplements and beef, which has a high iron load, were associated with rapid progression in this study, consistent with the suggestion that iron drives symptom progression due to its oxidative nature.8
While coenzyme Q10 (CoQ10) showed early promise in Parkinson’s disease, more recent randomized controlled trials failed to show benefit.9 It is interesting that the association between delayed progression and CoQ10 in this study was no longer statistically significant after adjustment for income. The author postulates that CoQ10, an expensive supplement, might be a surrogate for high income status which itself was associated with a delayed progression, possibly due to better access to health care.
This study has some excellent strengths. The researchers adjusted all results for age, gender, years since diagnosis, and income level, and the results give us some initial clues regarding the effect of diet and supplements on Parkinson’s disease. Of course, there are limitations to this study as well. As a cross-sectional analysis, conclusions from the study design are limited. This study is a longitudinal one and this publication is preliminary and not meant to be exhaustive. Also, the researchers did not correct the P-values for multiple comparisons so it is possible that some statistically significant associations may be spurious.
In summary, this study presents some interesting preliminary findings regarding diet and supplements for Parkinson’s disease. It is an important first step that will be followed up with further work by the study authors and other researchers.