Parkinson's is a progressive neurological disease affecting the "substantia nigra," a small area of cells in the midbrain. Degeneration of these cells results in a reduction in levels of the neurotransmitter dopamine. This deficiency upsets the balance between dopamine and another brain chemical, acetylcholine, and ultimately affects movement and coordination. The most familiar signs of the disease are tremor, or trembling in hands, arms, legs, jaw, and face; a generalized slowness of movement, stiff limbs, rigid facial expressions, and problems with balance or gait. Depression often precedes the physical signs, and mental function can deteriorate in advanced cases.
Mucuna (Mucuna pruriens) has long been used as a treatment for Parkinson's disease in Ayurvedic medicine, but few studies of its effects or effectiveness have been done in the West. The most notable was a very small clinical trial (only eight patients) carried out by British researchers who published their findings in 2004. The rationale for the use of mucuna is that it is a natural source of L-dopa (Levodopa), a compound which is converted to dopamine in the brain and has been used for many years to help relieve symptoms of Parkinson's. The British study compared the standard dose of L-dopa to a powdered preparation made from the seed of mucuna. It showed that the mucuna had a more rapid onset of action against Parkinson's symptoms and that its positive effects were longer lasting than those of Ldopa. Based on their findings, the investigators concluded that further and larger studies of the mucuna seed powder preparation are warranted, but to my knowledge, no human studies have been done since or are underway. The British research was published in the December, 2004, issue of the Journal of Neurology, Neurosurgery & Psychiatry.
Incidentally, fava beans are also a natural source of L-dopa, but you would have to eat a rather large amount - the equivalent of a 16-ounce can - to get an effective dose. I would not recommend adding either fava beans or mucuna to your diet if you're taking L-dopa for Parkinson's without discussing it with your doctor.
If you have Parkinson's symptoms, I recommend trying breath work, yoga and biofeedback to help reduce stress, which always worsens tremors. Acupuncture may also temporarily improve muscle function, and bodywork can relieve stiffness (I particularly recommend Trager work and the Feldenkrais method).
Andrew Weil, M.D.
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