There are no diets specific to Parkinson’s. However there are a variety of nutritional concerns that may arise as this disease progresses and there are a number of circumstances where nutrition becomes an issue. Weight changes, malnourishment, gastrointestinal dysfunction and interaction with Parkinson’s medications are but a few.
Both Parkinson’s disease and malnourishment contribute to poor life experience. A recent study evaluating patients for their nutritional status as well as their quality of life found that malnourished people with Parkinson’s had a poorer quality of life compared to well nourished patients. This was true particularly in the areas of mobility and activities of daily living. Therefore it makes sense that efforts to improve a patient’s quality of life effectively should also include evaluation of nutritional status.
(1) Weight loss: With regards to weight, patients with Parkinson’s disease are at high risk for having poor nutrition, weight loss and loss of muscle mass compared to healthy controls.
(2) Weight gain is also an issue for those with Parkinson’s. It is very common following surgical procedures such as deep brain stimulation which when successful, improves the symptoms of PD thereby reducing the amount of energy burned by dyskinesias and tremors. Dopamine agonists may cause compulsive eating as a side effect and MAO-B Inhibitors can also cause weight gain.
It is important for patients and their health care providers to keep track of body weight and to intervene early if any weight changes are noted. Review of functioning and a careful assessment by a registered dietician to identify why a patient is either losing or gaining weight and to address those issues, is important.
(3) Dysphagia or difficulty swallowing can be for both solids and liquids. Problems swallowing solids often results in weight loss while difficulty with liquids can result in aspiration. These issues usually are with more advanced disease although 60 – 80 % of PD patients have some sort of problem on testing whether they experience symptoms or not. This issue is best evaluated by a speech-language pathologist and in conjunction with a dietician; a specific type of diet can be developed with a variety of textures and consistencies depending on the severity of the problem.
(4) Gastric dysfunction: In PD, both early and late, the stomach doesn’t empty as quickly. So the transit time for food through the GI system is increased. This can lead to abdominal distention, discomfort, nausea and a feeling of being full with very little food intake. Obviously this can contribute to weight loss.
(5) Constipation: This is the most commonly reported GI symptom. Constipation is defined as less than 3 bowel movements per week. It’s due to the effect of PD on the intestine and also poor fiber and fluid intake.
(6) Interaction between diet and medications: The amino acids in protein and L-Dopa compete for absorption in the intestine and at the blood-brain barrier. This interferes with how well the drug works. It is recommended to take Levodopa on an empty stomach, ½ hour before meals or 2 hours after a meal containing protein.
However Parkinson’s medications, particularly levodopa, may cause nausea for many people when taken on an empty stomach. Eating light, bland foods (such as crackers) and having a cold drink with levodopa medications may help ease this symptom.
(7) Nutritional supplements: Due to an increased risk for osteoporosis in Parkinson’s, calcium and Vitamin D supplementation may be necessary. And although lacking in rigorous scientific evidence, there is a growing interest in those nutritional factors that are able to hinder the progression of Parkinson’s versus those that may further progression of the disease. A more detailed review can be found here.
So although there is no diet that has been developed specifically for Parkinson’s disease, there are a variety of illness-related scenarios where dietary adjustments are an important part of management.