The effect of dietary protein on the efficacy of L-dopa: A double-blind study

J. K. Tsui, S. Ross, K. Poulin, J. Douglas, D. Postnikoff, S. Calne, W. Woodward, D. B. Calne

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


We randomly placed 10 parkinsonian patients on high- and low-protein dieta that tasted and looked alike, each for 1 week. All patients were taking l-dopa and carbidopa with or without other antiparkinson medications; medications remained unchanged. A “blind” physician recorded the modified Columbia scores, objective measurements of rigidity, movement velocity, and pegboard tests three times a day for 5 days during each week. The patients recorded fluctuations hour to hour. We measured serial blood L-dopa levels on day 4 of each week. Performance was significantly better while the patients were on low-protein diets. These results did not correlate with blood L-dopa levels, which had higher peaks in three patients while they were on high-protein diets despite inferior performance and increased number of “off” hours. Thus, high dietary protein probably affects the efficacy of L-dopa at a central level.

Original languageEnglish (US)
Pages (from-to)549-552
Number of pages4
Issue number4
StatePublished - Apr 1989

ASJC Scopus subject areas

  • Clinical Neurology


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