Table 1.
Summary of Observational Study Results on the Impact of Diet and Dietary Patterns on PD.
| Citation | Year Published | Study Type | Diet Type | n | Location | Key Results |
|---|---|---|---|---|---|---|
| Alcalay et al. [128] | 2012 | Case-Control | MD | 257 cases 198 controls |
United States | Greater adherence to the MD was associated with a reduced risk of PD and later age-at-onset of PD. |
| Okubo et al. [77] | 2012 | Case-Control | Healthy Western Light Meal |
249 cases 368 controls |
Japan | The healthy dietary pattern was associated with a reduced risk of PD, but not statistically significant (p = 0.06). The light meal and Western dietary patterns were not associated with PD risk. |
| Sääksjärvi et al. [79] | 2012 | Cohort | AHEI | 4524 (85 cases) | Finland | Adherence to the AHEI was not associated with PD risk. Greater intake of berries was associated with a reduced risk of PD in women but was associated with an increased risk among men. |
| Virmani et al. [93] | 2016 | Cohort | PRD | 1037 (1037 cases) | United States | Only 5.9% of participants on levodopa reported PIL. Only 20 participants reported following a PRD. |
| Barichella et al. [91] | 2017 | Case-Control | PRD | 600 cases 600 controls |
Italy | Adherence to a PRD was associated with a lower levodopa dosage. Protein intake was not associated with levodopa-related motor complications. An intake of 10 g protein over 0.8 g/kg/day was associated with an increase in levodopa dosage by 0.7 mg/kg. |
| Cassani et al. [129] | 2017 | Case-Control | MD | 600 cases 600 controls |
Italy | No difference in adherence to the MD existed between cases and controls. Adherence to the MD was not associated with disease duration, or age-at-onset. |
| Mischley et al. [73] | 2017 | Cross-Sectional | General | 1053 (1053 cases) | United States | A plant/fish based dietary pattern was associated with a reduced rate of PD progression. Foods associated with a reduced rate: fresh vegetables, fresh fruit, nuts, seeds, fish, olive oil, coconut oil, and wine. Foods associated with an increased rate: canned vegetables, canned fruit, beef, fried food, cheese, yogurt, ice cream, and soda. |
| Agarwal et al. [82] | 2018 | Cohort | DASH MD MIND |
706 (302 cases) | United States | The DASH Diet was not associated with PD risk. Both the MIND diet and the MD were associated with a reduced risk of PD, with the MIND diet having the strongest relationship to PD risk. Each unit increase in the MIND diet score was associated with a 13% reduction in PD risk. |
| Maraki et al. [133] | 2018 | Cohort | MD | 1765 (34 cases) | Greece | Adherence to the MD was associated with a lower probability of prodromal PD. The study’s results remained unchanged after excluding constipation as a feature of prodromal PD. |
| Liu et al. [81] | 2020 | Cohort | DST | 3653 (47 cases) | United States | Greater diet quality was associated with a significantly reduced risk of PD. |
| Molsberry et al. [78] | 2020 | Cohort | MD AHEI |
17,400 | United States | Greater adherence to both the MD and AHEI was associated with a reduced risk of developing features of prodromal PD. |
| Metcalfe-Roach et al. [130] | 2021 | Case-Control | MD MIND |
167 cases 119 controls |
Canada | Greater adherence to the MIND diet or the Greek MD was associated with later age of onset of PD. The relationship was stronger for the MIND diet than the MD. The relationship between the MIND diet and age of onset was strongest among women, while the relationship between the MD (Panagiotakos et al. [134]) was strongest among men. |
| Yin et al. [131] | 2021 | Cohort | MD | 41,715 (101 cases) | Sweden | Greater adherence to the MD was associated with a reduced risk of PD. Each unit increase in MD score was associated with an 11% reduction in PD risk. |
Note: Table abbreviations include Dietary Approaches to Stop Hypertension (DASH); Dietary Screening Tool (DST); Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND); Mediterranean Diet (MD); Parkinson’s Disease (PD); Protein Interactions with Levodopa (PIL); Protein Restricted Diet (PRD); Sample Size (n).