The effect of a nicotine-rich diet with/without redistribution of dietary protein on motor indices in patients with Parkinson's disease: A randomized clinical trial

Background: The aim of designing this clinical trial is to investigate the impact of a nicotine-rich diet with/ without protein redistribution on the motor indices of patients with Parkinson's disease (PD). Methods: We randomly divided 45 patients (age > 50) with PD into three groups including: nicotine-rich diet (20 mu g per day) group (group N; n = 15), nicotine-rich diet with protein redistribution group (group N + P; n = 15), and control group (group C; n = 15). In all group, the diet was isocaloric, and participants received six meals and snacks. After 12 weeks, the Unified Parkinson's Disease Rating Scale part III (UPDRS), serum alpha-synuclein levels, serum apolipoprotein A1, serum cotinine, and anthropometric parameters were measured in the three groups before and 12 weeks after the beginning of the study. Results: All of the enrolled patients completed the study. The UPDRS score was improved by 1.47 and 1.95 units in the N and N + P groups compared to the placebo (P < 0.001). On the other hand, effect size of N and N + P diets for alpha-synuclein were -52.82 and -175.85, respectively. The differences were significant compared to the control group (P < 0.05). Also, the effect of the both diets on serum cotinine compared to the control group was significant (P < 0.05). Although the effect size for UPDRS, alpha-synuclein, and cotinine in N + P diet were higher than N group, the differences were not statistically significant (P > 0.05). Also, the obtained results showed that there were no significant effects on anthropometric variables and serum levels of Apolipoprotein A1 in dietreceiving groups (P > 0.05). Conclusions: The results of our study indicated that nicotine consumption in an isocaloric diet, while preventing a decrease in anthropometric indices, leads to improvements in motor indices and a reduction in alpha-synuclein levels. Additional and larger controlled trials are required to validate these findings.