Among patients with Parkinson disease or parkinsonism undergoing a 30-day multidisciplinary intensive rehabilitation treatment (MIRT), consumption of a twice-daily whey protein-based nutritional supplement enriched with leucine and vitamin D preserved muscle mass and improved lower extremity function, according to a study published in Neurology.

The Protein, Leucine and Vitamin D Enhancing Rehabilitation (PRO-LEADER; Identifier: NCT03124277) study, a bicentric, pragmatic, randomized, and assessor-blind controlled trial, was developed by investigators to evaluate the efficacy of muscle-targeted nutritional supplement support on MIRT functional outcomes of patients with Parkinson disease or parkinsonism (n=150). Patients were admitted to 1 of 2 rehabilitation care hospitals to treat reduced walking capacity, postural instability, or gait disturbances, and given a standard hospital diet with or without the twice-daily whey protein-based oral liquid supplement.

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Primary study endpoint was an increased distance during the 6-minute walking test (6MWT) at 30 days. Secondary endpoints included significant changes in the Self-assessment Parkinson Disease Disability Scale score, 4-meter walking speed, skeletal muscle mass, body weight, Timed Up and Go test (TUG), handgrip strength, and the Berg balance scale score.

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The MIRT program improved 6MWT performance in both study groups (P <.001). In primary efficacy analyses of the experimental population, twice-daily nutritional support resulted in greater distance increases during 6MWT (mean 69.6 meters; 95% CI, 60.7-78.6) compared with those receiving no nutritional support (51.8 meters; 95% CI, 37.0-66.7), with a center-adjusted mean difference of 18.1 meters (95% CI, 0.9-35.3; P =.039).

After adjusting for changes in dopaminergic therapy and skeletal muscle mass, the mean difference computed in the randomized population was 18.0 meters (95% CI, 0.7-35.2) (P =.043). No substantial interactions between treatment effect and baseline features (Hoehn & Yahr stage, age, protein intake, adherence to a protein redistribution diet, and vitamin D status) were suggested in subgroup analyses. For the secondary endpoints, a meaningful effect was found for TUG (P =.046), 4-meter walking speed (P =.032), handgrip strength (P =.068), and preserved muscle mass (P =.029). Six patients discontinued taking the supplement due to mild side effects.

The study limitations included the absence of an isocaloric placebo group and the use of bioelectric impedance analysis. Nevertheless, study investigators concluded that,“[o]verall, the use of muscle-targeted nutritional support may be proposed to patients as an integral part of MIRT in this patient population.” They do, however, caution that, “confirmatory studies are required.”


Barichella M, Cereda E, Pinelli G, et al. Muscle-targeted nutritional support for rehabilitation in patients with parkinsonian syndrome. Neurology. 2019;93(7).