Dietary protein and orally administered levodopa, the primary anti-Parkinson’s medication, can compete for absorption into the bloodstream. Levodopa is a large molecule amino acid structure that, to be absorbed into the bloodstream, requires attachment to a carrier molecule. The availability of these carriers is limited during each digestive “transport,” and they accept large molecule amino acids from other dietary sources as well. Once these carrier molecules are all attached, any remaining large molecule amino acids are passed on through the digestive system and eventually become waste.
In the early stages of Parkinson’s disease it is not a problem for most people that only small amounts of dopamine need to eventually get to the brain. Even small doses contain much more than their brain requires, so that lost in the gut is of no consequence. As the Parkinson’s progresses and symptom management requires higher dosages of levodopa, it becomes necessary to manage its absorption better. The most effective way to do this is to separate dietary protein from levodopa dosages.
• During waking hours when levodopa doses are highest, eat primarily fruits, vegetables, whole grains, and whole grain products. Avoid dairy products, meats, nuts, and legumes (dried beans), all of which are high in protein.
• Eat five or six small meals spread throughout the day to help to counter feelings of hunger and to increase the nutritional value of the day’s food intake.
• Incorporate the day’s protein into the evening meal, or other meals that follow at least one hour after the last and at least two hours before the next dose of levodopa. An adult should consume two or three servings of protein (50 to 60 grams) daily.
Taking levodopa doses with meals that do not contain protein allows the food to neutralize the nausea that levodopa can cause but does not provide competition for absorption.