To investigate a possible role for this substance in the treatment of Parkinsonian motor oscillations, we carried out single dose studies of Vicia faba pod mixture plus carbidopa in six patients. Motor responses of equivalent magnitude to those of conventional L-dopa medication occurred in five cases with mean onset of 39 min and mean duration of 104 min. Vicia faba contains sufficient L-dopa to be pharmacologically active in patients with Parkinson's disease and can potentially be incorporated into dietary strategies to manage Parkinsonian motor oscillations. Introduction Pharmacological treatment of Parkinson's disease with L-dopa is the most practical and physiological way to ameliorate the underlying deficiency of endogenous dopamine release in the striatum. Diet, particularly protein intake, contributes to this effect and manipulation of dietary intake has been proposed as a method to reduce fluctuations of L-dopa delivery to the brain.
Food can also be a source of L-dopa.
In 1913, Guggenheim first isolated dihydroxyphenylalanine in its levorotatory form after extracting it from Vicia faba beans 1 . He was also first to demonstrate a pharmacological action of L-dopa when he ingested some of his bean extract and became nauseated. He found the bean pods to be a richer source of L-dopa than the beans. We have studied the responses to single doses of broad bean mixture to investigate its possible use in the management of Parkinsonian motor oscillations. Patients and methods Six patients on chronic conventional L-dopa therapy complicated by moderate to severe motor oscillations were studied.