Pilot dietary study with normoproteic protein-redistributed plant-food diet and motor performance in patients with Parkinson’s disease Luciana Baroni 1 , Chiara Bonetto 2 , Francesca Tessan 1 , Dario Goldin 3 , Lorenzo Cenci 4 , Patrizia Magnanini 4 , Giovanni Zuliani 5 1 Department of Neurorehabilitation, Villa Salus Hospital, Venice-Mestre, Italy, 2 Department of Public Health and Community Medicine, Section of Psychiatry and Clinical Psychology, University of Verona, Italy, 3 Department of Internal Medicine, Villa Salus Hospital, Venice-Mestre, Italy, 4 Service of Nutrition, General Hospital, Padua, Italy, 5 Department of Clinical and Experimental Medicine, Section of Internal Medicine, Gerontology and Geriatrics, University of Ferrara, Italy Although a plant-based diet can provide some benefits in Parkinson’s disease (PD), no study to date has evaluated the effectiveness of a plant-food diet in the management of the disease. In this pilot study, we compared the effect of a plant-food menu (PFD) and of a omnivorous menu on motor performance of 25 PD patients, 12 in the intervention group (PDi) and 13 in the control group (PDc). After 4 weeks, the PDi group showed a significant reduction (Mann–Whitney test) in the Unified Parkinson’s Disease Rating Scale, total score (47.67 vs. 74.46, P = 0.008) and sub-score III motor performances (25.42 vs. 46.46, P = 0.001), and the modified Hoehn and Yahr Staging Scale (1.96 vs. 3.15, P = 0.005). These data suggest that PFD may be useful in the management of PD patients by improving their motor performances. Additional studies are needed in order to confirm these preliminary results. Keywords: Levodopa, Motor performance, Parkinson’s disease, Plant-food diet, Protein, Vegan diet Introduction Parkinson’ s disease (PD) occurs worldwide, with equal incidence in both sexes. The overall age-adjusted prevalence is 1% worldwide, and 1.6% in Europe, rising from 0.6% at age 60–64 to 3.5% at age 85–89. 1,2 The aetiology is still unclear, but it is accepted that PD may represent different conditions with a final common pathway. Research suggests that PD patients may be affected by a combination of genetic and environmental factors. 3–9 Nutrition seems to be directly involved in increasing PD risk, mainly with respect to high dietary intakes of animal fat 10,11 and dairy products. 12,13 Two recent studies have shown that a plant-based dietary pattern may protect against PD. 14,15 Food appears also to affect the pharmacokinetic and pharmacodynamic of levodopa, a prodrug of dopamine (both derived from the amino acid tyro- sine), which remains the most effective agent to allevi- ate motor dysfunction in PD. L-Dopa can enter the brain and be decarboxylated to dopamine only after crossing the blood–brain barrier by means of a specific saturable carrier system (the large neutral amino acid transporter, LAT). At this level, it competes with some dietary essential amino acids (the large neutral amino acid, LNAA, including tyrosine) which block L-dopa entry into the brain, even if blood concen- trations of the drug are adequate. 16 So preventing a high-protein dietary intake may contrast the reduced levodopa effects following the competition between food-derived amino acid and levodopa across the blood–brain barrier. 17,18 To avoid the risk of nutritional deficiencies linked to an extreme restriction in total protein intake, some authors proposed the ‘protein redistribution diet’. This intervention consists of a normoproteic diet ( protein calories about 10–15% of total calories, about 0.8–1.0 g/kg/day) with the main protein intake concentrated in the evening meal, in order to limit the negative interaction of LNAA on L-dopa response at daytime, and let the negative effect act at night-time during the sleep, 19 while respecting the protein requests. When this diet was tested, a positive Correspondence to: Luciana Baroni, Department of Neurorehabilitation, Villa Salus Hospital, via Terraglio, 114-30174 Venice-Mestre, Italy. E-mail: luciana_baroni@yahoo.it © W.S. Maney & Son Ltd. 2011 DOI 10.1179/174313211X12966635733231 Nutritional Neuroscience 2011 VOL. 14 NO. 1 1