Low-Protein Diet/Protein Meal Redistribution
L-DOPA therapy is hindered by many obstacles, one of which is excess protein (specifically, aromatic amino acids) competing with L-DOPA for transport into the brain. Therefore, some studies have evaluated the effects of engaging in protein meal redistribution, involving eating dietary protein separate from dosing with L-DOPA.
Current research indicates that protein meal redistribution may be favorable with a low protein diet. It appears that protein meal redistribution reduces fluctuations, or "on-off periods" in response to L-DOPA therapy.121 Taking L-DOPA at least 30 minutes before consuming protein and/or having your highest protein meal at a time when L-DOPA is not needed may be an effective strategy. However, patients should speak with their physician to determine which dieting approach is appropriate for them.
Coffee contains a multitude of pharmacologically active compounds, some of which have been shown to suppress oxidative stress and protect against diabetes, cancer, cognitive decline, and so on.122 Additionally, several epidemiological studies have found that those who consume large amounts of coffee are much less likely to develop Parkinson's disease.105,123,124
Coffee constituents (compounds) protect brain cells which can be extremely beneficial for Parkinson's disease patients. Coffee extracts have been shown to inhibit MAO-A and -B enzymes, a mechanism similar to that of some pharmaceutical Parkinson's therapies.125 Experimental models suggest that coffee constituents promote neuronal development and increase antioxidant defense systems in the brain.126,127
Green coffee extract contains more of the active antioxidant compounds than brewed coffee, and may be a promising option for Parkinson's disease patients.128 However, clinical trials have yet to confirm this potential benefit.
Intriguing research suggests that caffeine itself may be a potent anti-Parkinson agent. Upon ingestion, caffeine readily crosses the blood-brain barrier and blocks adenosine receptors, an effect responsible for many of its pharmacologic actions. The adenosine receptor system interacts with the dopaminergic system in several ways.129 Experimental studies have shown that caffeine binds to presynaptic adenosine receptors causing an increase in dopamine release, thereby temporarily ameliorating some symptoms of Parkinson's disease.130 In fact, some data from non-human primate studies indicate that adenosine receptor antagonists, like caffeine, may allow for a reduced dosage of L-DOPA. Data in mice also supports this notion, but more studies need to be done.131,132
In a clinical trial, a daily caffeine dose of 100 mg was shown to reduce "freezing." However, it appeared the subjects developed a tolerance after a few months. The researchers went on to suggest that caffeine might have therapeutic potential, but a periodic 2-week abstinence period may be required to maintain long term effectiveness.133
Current evidence suggests that coffee consumption may provide some neuroprotection and pharmacologic support, with very little potential downside for Parkinson's patients.