Dietary Supplement Use Is High Among Individuals With Parkinson Disease

Christine C. Ferguson, MS, RD; Linda L. Knol, PhD, RD; Anne Halli-Tierney, MD; Amy C. Ellis, PhD, RD


South Med J. 2019;112(12):621-625. 

In This Article


The results of this study reveal a high rate of dietary supplement use by those with PD. Vitamin D, multivitamins, vitamin B12, fish oil, melatonin, CoQ10, and calcium were the most commonly taken; however, a wide variety of supplements were reported. Dietary supplement users and nonusers did not differ by sex, age, education level, income level, or disease duration. It was interesting that nearly one-third of dietary supplement users denied speaking with a healthcare professional about their use. These findings suggest that the use of dietary supplements is high among the PD population, and they also indicate the need for better dialog between patients and practitioners about supplement use.

The majority of respondents, 83.4% (171/205), reported taking ≤1 dietary supplement in the previous 30 days. According to National Health and Nutrition Examination Survey data, this is higher than the general US population of older adults (70%).[3] This is also higher than the 2006 findings of Wolfrath et al, reporting that 63.3% of patients with PD used nutritional supplements.[5] Among our nationwide sample, 94 different types of dietary supplements were reported. This suggests that those with PD may try to self-treat their PD-related symptoms and disease progression with dietary supplements.[2,9] Because the regulation of dietary supplements by the US Food and Drug Administration is much less stringent than that of medications, this raises concerns that there may be unintended adverse effects such as drug–supplement interactions.[1] The body of research remains limited in supporting the use of any of these dietary supplements to improve PD symptoms and progression.[2]

The most common dietary supplements used by at least one-third of respondents were vitamin D, multivitamins, vitamin B12, fish oil, melatonin, CoQ10, and calcium. In 2006, Wolfrath et al found that multivitamins, calcium, vitamin C, and vitamin E were the dietary supplements most used by individuals with PD.[5] In contrast, in the present study, only 6.4% and 20.5% of respondents reported taking vitamin C and vitamin E, respectively. At least half of respondents reported taking vitamin B12, melatonin, CoQ10, vitamin B6, folate, NAC, and Mucuna pruriens specifically for PD. Many of these compounds have been shown to have antioxidant functions, and thus it is plausible that they may ameliorate PD disease progression by reducing oxidative stress.[2,9–15] To date, however, research is lacking to establish conclusive recommendations for any of these dietary supplements. Future studies are warranted to investigate the effects of these dietary supplements on PD progression because they are commonly taken for PD and PD-related symptoms.

The results of this study found no statistically significant associations between dietary supplement use and the demographic variables considered. The insignificant findings regarding education could reflect the highly educated sample of respondents. Other demographic variables used in data analysis did not yield significant findings, but results suggest having PD itself may be a predictor of dietary supplement use. This is indicated by the high percentages of respondents reporting using individual supplements specifically for PD and the initiation of supplement use postdiagnosis. Dietary supplement use and other forms of complementary and alternative medicine have been characterized in other neurological diseases such as multiple sclerosis,[16–18] amyotrophic lateral sclerosis,[19] and dementia.[20] O'Connor et al reported that use of dietary supplements also increased after diagnosis of multiple sclerosis, which is consistent with our results in respondents with PD.[18] It would be interesting if future research could comprehensively investigate how health behaviors differ before and after being diagnosed as having a neurological disease.

A greater percentage of respondents in our study reported discussing their dietary supplement use with a healthcare professional than Wolfrath and colleagues' participants in 2006: 70.8% versus 47%, respectively.[5] Potential reasons for this increase may include healthcare professionals discussing dietary supplements with patients, or it may be the result of those with PD recognizing that dietary supplements have the potential to interact with medications. Nevertheless, it is still alarming that more than one in four participants in the present study denied speaking with a healthcare professional about their supplement use. Future qualitative studies should investigate what hinders or facilitates those with PD to speak about dietary supplement use with healthcare professionals such as physicians, pharmacists, or registered dietitians.

The limitations of this study include the cross-sectional design and inherent limitations of survey methods. Convenience sampling using an online survey tool introduces sampling bias that could lead to an underrepresentation of certain groups of patients with PD. For example, our cohort was predominantly white and highly educated. Results may not be extrapolated to individuals with PD of other ethnic groups or education levels or older adults who may not be using online platforms. Self-selection bias may have affected the sample of respondents, because they may have been more willing to participate in the survey if they used dietary supplements.

In this sample of online PD support group participants, findings indicate that dietary supplement use is widespread among individuals with PD. The most commonly used supplements in this population include vitamin D, multivitamins, vitamin B12, fish oil, melatonin, CoQ10, and calcium; furthermore, participants reported using 94 different types of dietary supplements. Although most dietary supplement users reported speaking with a healthcare practitioner about their dietary supplement use, results reveal a need for healthcare providers to inquire about dietary supplements when conversing with patients with PD. Because dietary supplement use is so prevalent among individuals with PD, future studies are warranted to investigate the efficacy of these compounds in attenuating disease progression.