Diet quality and Parkinson’s disease: Potential strategies for non-motor symptom management

Introduction: Parkinson’s disease (PD) is now considered a systemic disease, and some phenotypes may be modifiable by diet. We will compare the diet quality and intake of specific nutrients and food groups of PD patients with household and community controls to examine how diet may influence PD clinical features. Methods: We conducted a case-control study of 98 PD patients and 83 controls (household = 53; community = 30) in central California, assessing dietary habits over the past month and calculating the Healthy Eating Index (HEI)-2015. We employed multivariate logistic and linear regression analyses to assess associations between diet and PD status, PD symptom profiles, and medication, adjusting for relevant confounders. Results: PD patients had a lower HEI score than controls, with an OR of 0.65 (95% CI: 0.45, 0.94) per 10-points increase in HEI. Lower-quality diet was characterized by higher intakes of carbohydrates, total and added sugars, and trans fats and lower intakes of fiber, folate, unsaturated fatty acids, protein, and fat. PD patients with chronic constipation had a 4.84 point lower HEI score than those without (β per 10-point in HEI: −0.48; 95% CI: −0.97, −0.00). Furthermore, patients on high dopamine agonist doses consumed more sugar than those on lower doses. Conclusion: PD patients consume a lower-quality diet compared to household and community controls. Dietary modifications may alleviate non-motor symptoms like constipation, and promoting a healthy diet should become a part of routine care and disease management for PD patients, with special attention on agonist-treated and hyposmic patients.


I. Dietary patterns
The National Cancer Institute questionnaire allowed us to generate three different diet quality scores to assess dietary patterns: the HEI-2015 [1], AHEI-2010 [2], and aMED [3] according to validated analytical procedures for this instrument (Table S1).Specifically, the HEI-2015 was developed based on the Update of the Healthy Eating Index [1] and contains 13 components (total vegetables, greens and beans, total fruit, whole fruit, whole grains, refined grains, dairy, total meat, seafood or plant protein, fatty acids, polyunsaturated to saturated fatty acid ratio, sodium, and added sugars) reflecting recommendations based on 2015-2020 Dietary Guidelines for Americans.
The intake of foods and nutrients is represented on a density basis, as amount per 1,000 kcal.Each component is scored from 0 (indicating worst diet quality) to 5 or 10 (indicating best diet quality).
Better scores are given to a higher intake of vegetables, fruits, whole grains, dairy, seafood or plant protein, polyunsaturated to saturated fatty acid ratio; a lower intake of refined grains, total meat, and added sugars.Thus, the total HEI ranges from 0 (worst) to 100 (best) points.
The AHEI was developed to improve on disease risk prediction [2].The AHEI-2010 includes 11 components (vegetables, fruits, whole grains, juice, nuts and legumes, red and processed meat, trans fats, long-chain fats, polyunsaturated fatty acid, sodium, and alcohol), each with a score of 0 (indicating worst diet quality) to 10 (indicating best diet quality) and a total score ranging from 0 (worst) to 110 (best) points.Better scores are assigned to a higher intake of vegetables, fruits, whole grains, nuts and legumes, long-chain fats, and polyunsaturated fatty acids; a lower intake of juice, red and processed meat, trans fats, and sodium; and a light to moderate intake of alcohol.
The aMED is based on the traditional Mediterranean diet scale in the Greek population [4,5].This scale was modified using a food frequency questionnaire developed for the United States population's diet [3,6] and is based on the intake of 9 components (vegetables without potato products, fruits, whole grains, nuts, legumes, fish, polyunsaturated to saturated fatty acid ratio, red and processed meat, and alcohol).For intake of the first seven items above the median of all study subjects, a person receives 1 point (indicating adherence); all others reporting less receive a 0 (indicating nonadherence).For alcohol, 1 point is assigned for intake between 5 and 15 g/d (Table S1).For red and processed meat, an intake below the median receives 1 point.Adherence corresponds to a higher intake of vegetables, fruits, whole grains, nuts, legumes, fish, and polyunsaturated to saturated fatty acid ratio; a lower intake of red and processed meat; and a light to moderate intake of alcohol.The total score ranges from 0 (worst) to 9 (best) points.b UPDRS IB non-motor aspects of experiences of daily living items (present: ³ 9 points; absent: < 9 points).c NMSS daytime sleepiness frequency ´ severity score (present: > 0 point ; absent: 0 point).d NMSS restless sleep frequency ´ severity score (present: > 0 point ; absent: 0 point).e MMSE cognitive impairment score (present: < 24 points ; absent: ³ 24 points).f UPDRS III motor symptom severity and progression (present: ³ 35 points; absent < 35 points).

Table S3 .
Association of dietary patterns and components with Parkinson's disease status according to constipation (N = 181) Adjusted for age, gender, smoking, BMI, and energy intake.

Table S4 .
Association of dietary patterns and components with Parkinson's disease according to gender (N = 181) Adjusted for age, smoking, BMI, and energy intake. a

Table S5 .
Associations of dietary patterns and components with Parkinson's disease status using conditional logistic regression with matched pairs (n = 166) Adjusted for age, gender, smoking status, BMI, and energy intake. a

Table S6 .
Association of Parkinson's duration and age at diagnosis with specific nutrient intake SD, standard deviation; PD, Parkinson's disease; CI, confidence interval.a Coefficients are from linear regressions of nutrients on PD duration and age at diagnosis.Adjusted for age and gender.

Table S7 .
Association of Parkinson's disease clinical features with diet (n = 98) Parkinson's disease; UPDRS, Unified Parkinson's Disease Rating Scale; NMSS, Non-Motor Symptom Assessment Scale; MMSE, Mini Mental State Exam; HEI, Healthy Eating Index; AHEI, Alternate Healthy Eating Index; aMED, alternate Mediterranean Diet score.a Coeffcients are from linear regressions of dietary patterns and components on clinical features.Adjusted for age and gender.