title: Amount and distribution of dietary protein affects clinical response to levodopa in Parkinson's disease.
abstract: Reducing dietary protein improves the effectiveness of levodopa (LD) but the most effective distribution of a low-protein diet (0.8 g/kg) is unclear. We compared a 1.6 g/kg protein diet, a 0.8 g/kg diet with protein evenly distributed between meals, and a 0.8 g/kg diet with protein restricted to the evening meal in 5 parkinsonian patients with motor fluctuations. We monitored clinical response, plasma LD, and plasma large amino acids (LNAAs) hourly throughout the day. Mean "on" times were 51% (1.6 g/kg diet), 67% (0.8 g/kg evenly distributed), and 77% (0.8 g/kg restricted). Hourly averages of plasma LD did not differ between the diets. The mean plasma LNAAs were 732 nmol/ml (1.6 g/kg diet), 640 (0.8 g/kg distributed), and 542 (0.8 g/kg restricted), and the diurnal pattern reflected the distribution of protein intake. In conclusion, the amount and distribution of dietary protein affect clinical response to LD. These effects are not related to LD absorption but are explained by the variation in plasma LNAAs.
authors.affiliation: Department of Neurology, Oregon Health Sciences University, Portland 97201.
authors.forename: J H
authors.initials: JH
authors.lastname: Carter
authors.forename: J G
authors.initials: JG
authors.lastname: Nutt
authors.forename: W R
authors.initials: WR
authors.lastname: Woodward
authors.forename: L F
authors.initials: LF
authors.lastname: Hatcher
authors.forename: T L
authors.initials: TL
authors.lastname: Trotman
mesh_terms: D000368:Aged; D000596:Amino Acids / Q000097:blood; D002230:Carbidopa / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D004044:Dietary Proteins; D004338:Drug Combinations; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008875:Middle Aged; D010300:Parkinson Disease / Q000178:diet therapy / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D004338:Drug Combinations; D007980:Levodopa; D002230:Carbidopa