Parkinson’s disease (PD) is an age-related neurodegenerative disorder that affects 1–2% of persons aged 60 years and older (Olanow et al, 2009). It is characterized by the loss of brain cells that produce dopamine, a chemical that helps direct muscle activity. There are diminished levels of dopamine at the basal ganglia of the brain, causing tremor of hands, arms, legs, jaw and face; rigidity of limbs and trunk; slowness of gait; coordination difficulty; chewing problems; dysphagia and problems with speech. Esophageal motor abnormalities and constipation are common. Constipation appears about 10–20 years prior to motor symptoms (Ueki and Otsuka, 2004). Unintentional weight loss is frequent, resulting in increased morbidity and mortality. Weight loss occurs from increased energy expenditure due to tremor, dyskinesias and rigidity; reduced energy intake due to olfactory dysfunction, cognitive impairment, depression, dysphagia and disability; and medication-related side effects, including dry mouth, nausea/vomiting, appetite loss, anorexia, insomnia, fatigue and anxiety.
Objectives of Medical Nutrition Therapy
Provide adequate energy to prevent weight loss, and avoid gaining excessive weight as well.
Provide adequate hydration, especially when thickened liquids are needed.
Maintain optimal physical and emotional health. Exercise may be protective, especially for men (Carne et al, 2005).
Supply dopamine to the brain; monitor diet therapy accordingly.
Improve the ability to eat.
Use semisolid foods rather than fluids when sucking/swallowing reflexes are reduced. Drooling may be a problem. Request a swallow evaluation from a speech therapist to determine proper consistency of foods.
Correct alterations in GI function (i.e., increased transit time, heartburn and constipation).
When using monoamine oxidase inhibitors, use a tyramine-restricted diet to prevent severe headaches, blurred vision, difficulty thinking, seizures, chest pain or symptoms of a stroke.
Medical Nutrition Therapy Intervention
Energy: Provide 25 kcal/kg IBW. If needed, increase the calories to 30 kcal/kg IBW to prevent weight loss.
Protein: A high intake of protein diminishes the effectiveness of levodopa. If weight loss occurs, provide 1–1.5 g/kg plus extra energy as needed. A protein redistribution diet is used since protein is a versatile nutrient (i.e., low-protein breakfast and lunch with high-protein dinner and snack). Foods that are rich in high biological value proteins are prescribed. Timing of levodopa should be monitored to avoid conflicting responses to protein at mealtimes.
Protein and the Brain: Tyrosine, an essential amino acid, is very much needed to help nerve cells produce enough dopamine. In Parkinson’s it is diminished for the better absorption of the levodopa therapy – protein redistribution diet is followed (major allowance is shifted to the latter half of the day).
Fibre: Increase fibre intake. To increase fibre, add smoothies to diet; crushed bran is also preferred.
Vitamins & Minerals: A multivitamin–mineral supplement may be beneficial, especially vitamins C, D, E and the B-complex vitamins. Folate and vitamins B6 and B12 are important to lower elevated triglyceride homocysteine levels (Biselli et al, 2007; Grimble, 2006).
Provide 3 major meals and 3 minor meals to the patient.
Plan diet according to results of swallowing evaluation. Cut, mince or soften foods as required.
Vegetable oils, salad dressings, nuts, green tea, coffee, turmeric and antioxidant-rich fruits and vegetables can be used.
If needed, follow the tyramine-restricted diet - avoid aged and fermented meats, organ meats, sausages, broad bean pods, sauerkraut, aged cheeses, and over-the-counter supplements containing tyramine and soybean products such as soy sauce.