Parkinson's disease, or PD, is a neurological disorder resulting from the loss of brain cells that produce dopamine, a neurotransmitter. PD causes motor function loss, as seen by tremors, rigidity, slow movement and impaired balance and coordination. There is no cure for PD, but symptoms and progression can be managed with drug therapy. Usually a combination of two drugs, carbidopa and levodopa, is given. The function of levodopa, given alone or in combination, can be altered by high levels of dietary protein.
Carbidopa and Levodopa Function
Levodopa converts to dopamine in the body; this is important, because dopamine is lacking in PD patients and is necessary for proper motor function. Carbidopa delays this conversion until the levodopa reaches the brain, where dopamine is needed. These drugs work together to help relieve symptoms of loss of motor function. Carbidopa and levodopa are combined in several brands of medications, including Sinemet, Parcopa and Atamet.
Levodopa and Protein
Protein can interfere with the absorption of levodopa into the bloodstream from the intestine and can also stop it from leaving the bloodstream and entering the brain. This is because levodopa is made from an amino acid, L-tyrosine, which is a building block and component of protein, making it similar in structure to dietary protein. When protein is digested, it is broken down into individual amino acids, competing with levodopa for absorption into the bloodstream. If too much dietary protein is present, not all of the levodopa will be absorbed.
Protein Requirements
Protein requirements in a healthy person are 0.8 grams per kilogram of body weight, or approximately 0.36 grams per pound of body weight. With certain medical conditions, this number may be increased to prevent weight loss; however, in people with Parkinson's disease, this is not recommended as a high protein diet can interfere with medications.
Tips
Take your medication an hour before eating a meal, so that protein does not interfere with its absorption. If you must take it with food, have a small amount of a low-protein food, such as crackers or fruit. Other low protein foods are vegetables, broth based soups and most refined grains, including white bread, white rice and cereal. Save large meals for times when you do not take your medication to ensure that you are getting your full dose.
Considerations
Other medications for Parkinson's disease may have food or drug-related interactions. These interactions may be dangerous, as they can alter the way in which your medication works. Speak with your doctor or pharmacist to find out specific interactions of your medications and how to best manage them.
References
- National Parkinson Foundation: Carbidopa/Levodopa
- The American Parkinson Disease Association, Inc.; Good Nutrition in Parkinson's Disease; Julie H. Carter, RN; 1999
- National Institute of Neurological Disorders and Stroke; Parkinson's Disease Information Page; July 2007
- Central Ohio Parkinsons Society; The Effects of Food and Over-the-Counter Medications on Parkinson's Disease and its Treatment; David Purdy, PharmD
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