The effects of omega-3 fatty acids and vitamin E co-supplementation on clinical and metabolic status in patients with Parkinson's disease: A randomized, double-blind, placebo-controlled trial
Introduction
Parkinson's disease (PD) is a progressive disorder influencing more than 3% of subjects with age over 75 years (de Lau and Breteler, 2006). Prior studies have demonstrated that the pathological marking of PD is the intraneuronal reposition of uncommon filamentous inclusions containing phosphorylated α-synuclein (phosαSYN) (Jellinger, 2003, Braak and Del Tredici, 2008). In addition, increased oxidative stress involves early events associated with dopaminergic neuronal degeneration in PD (Lv et al., 2015). Neuroendocrine abnormalities including glucose intolerance, insulin resistance and bone metabolism, and body weight changes are also common in PD (De Pablo-Fernandez et al., 2017).
Previous reports have indicated that omega-3 fatty acids deficiency can reduce the nigrostriatal system's ability to maintain homeostasis under oxidative conditions, which may increase the risk of PD (Fabelo et al., 2011, Cardoso et al., 2014). Furthermore, few researchers have exhibited that concentrations of vitamin E were lower in PD patients than healthy subjects (Paraskevas et al., 2003, Fukushima et al., 2011). Our previous study among gestational diabetes (GDM) have demonstrated that co-supplementation with 1000 mg omega-3 fatty acids and 400 IU vitamin E daily for 6 weeks increased total antioxidant capacity (TAC) and nitric oxide (NO), and decreased malondialdehyde (MDA) values, but unaltered glutathione (GSH) and high-sensitivity C-reactive protein (hs-CRP) levels (Jamilian et al., 2016). However, no significant effect in indices of oxidative stress and/or inflammation was seen following supplementation with omega-3 fatty acids in healthy adults for 4 weeks (Cunnane et al., 1995) and vitamin E in hemodialysis (HD) people for 8 weeks (Ahmadi et al., 2013).
Omega-3 and vitamin E may result in improved clinical signs, indices of inflammation and oxidative stress, and metabolic status through their effects on modifications in the dopamine metabolism (Cardoso et al., 2014), decreased inflammatory markers (Zhuang et al., 2013), reducing production of reactive oxygen species (ROS) in the mitochondria (Capo et al., 2015) and improved antioxidant defense (Gupta et al., 2011). However, whether omega-3 and vitamin E co-supplementation have direct benefits on clinical signs, biomarkers of inflammation and oxidative stress, and metabolic parameters in people with PD has to date not been evaluated. This intervention was, therefore, performed to determine the effects of omega-3 and vitamin E co-supplementation on clinical signs, indices of inflammation and oxidative stress, and metabolic parameters in people with PD.
Section snippets
Participants
This treatment, registered in the Iranian website for registration of clinical trials (http://www.irct.ir: IRCT201604035623N73), was a randomized, double-blind, placebo-controlled clinical trial that was done among people with PD aged 50–80 years old diagnosed according to clinical diagnostic criteria of the UK PD Society Brain Bank (Hughes et al., 1992) referred to the Shahid Beheshti Clinic in Kashan, Iran, between March 2016 and June 2016. The diagnosis of PD was confirmed by 2 neurologists.
Results
Among subjects in the supplements and placebo groups, 3 people [withdrawn (n = 3)] were excluded (Fig. 1). In the end, 54 subjects [omega-3 and vitamin E (n = 27) and placebo (n = 27)] completed the trial. However, as the analysis was based on the ITT principle, all 60 people (30 in each group) were included in the final analysis.
Distribution of gender, disease severity, mean age, height, weight and BMI as well as METs at week 0 and week 12 were not different between the two groups (Table 1).
Discussion
In this research, we evaluated the effects of omega-3 and vitamin E co-supplementation on clinical signs and metabolic indices in people with PD. We found that omega-3 fatty acids and vitamin E co-supplementation for 12 weeks in patients with PD had favorable effects on UPDRS, serum hs-CRP, plasma TAC, GSH and markers of insulin metabolism, but did not affect other indices of inflammation and oxidative stress, and lipid profiles. To our knowledge, this trial is the first to have assessed the
Conclusions
Overall, our study demonstrated that omega-3 fatty acids and vitamin E co-supplementation in people with PD had favorable effects on UPDRS, hs-CRP, TAC, GSH and markers of insulin metabolism, whereas it did not affect other biomarkers of inflammation and oxidative stress, and lipid profiles.
Conflicts of interest
No conflicts are declared.
Author contributions
ZA and MT contributed in conception, design, statistical analysis and drafting of the manuscript. O-RT, ED, RD-K, FB, JA, M-HA, EK and M-RM. contributed in conception, data collection and manuscript drafting. The final version was confirmed by all authors for submission.
Clinical registration
http://www.irct.ir: IRCT201604035623N73.
Acknowledgements
The present study was supported by a grant from the Vice-chancellor for Research, KUMS, and Iran (94141).
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