Parkinson's disease is a brain disorder which occurs when certain nerve cells or neurons are damaged and the brain part called substantia nigra become impaired. Symptoms of Parkinsonís disease appear when cells producing a vital chemical called dopamine diminish in the body, which leads to lack of coordination between bodyís muscles and therefore interferes with movement.
Parkinsonís disease results due to an interaction between inheritance and environmental factors. There is a marked loss of dopaminergic neurons (pigmented cells) in the substantia nigra as well as of tyrosine hydroxylase, the rate-limiting enzyme for dopamine. Three theories are postulated for the cause of Parkinsonís disease: altered dopamine metabolism due to neural injury, exposure to environmental neurotoxins, and predisposition theory.
Nutrition plays a very important role in the management of Parkinsonís disease. Nutrition does not cure its progression but impacts many aspects of health. Parkinsonís disease can slow down the peristaltic movements of the digestive tract, causing constipation, slowed stomach emptying, and swallowing problems; it can lead to loss of the sense of smell, and of taste. Patients with Parkinsonís disease are at increased risk for malnutrition; yet, with attention to diet, one feels better and can prevent hospitalization.
Medications used to treat this disease can cause nausea and appetite loss. Also, one of the most important medications, levodopa, must compete with protein for absorption from the small intestine.
There is no single optimal diet for Parkinsonís disease. The diet depends on the dietary needs of the patient based on the age, gender and other complications like hypertension, diabetes mellitus, food allergies, etc. Also, medications for Parkinsonís disease and other medications like those taken for heart disease may have side effects, according to which the diet may have to be altered.
The aim of diet therapy in patients with Parkinsonís disease is to identify nutritional inadequacies at an early stage, implement measures to correct deficiencies or nutrition-related problems, find ways to minimize any practical difficulties associated with eating or swallowing, prevent undesirable weight gain or loss, lessen the impact of drug-therapy side effects on dietary intake, and monitor the patientís nutritional status as the disease progresses.
Nutritional Management in Parkinsonís Disease
Regulation of intake of proteins, carbohydrates, fluids, fibers and some other nutrients is very important in the nutritional management of Parkinsonís disease.
Most important concerns of Parkinsonís disease that require diet modification are bone thinning, dehydration, bowel impaction, unplanned weight loss, medication side effects, and protein-drug interaction.
► Protein regulation in Parkinsonís disease: Along with a balanced diet, about 0.5 g of protein/ kg body weight/ day (25-35 g protein per day) is recommended. This amount is divided equally among three meals, morning, midday, and dinner. Some scientists suggest that use of protein-restricted diet is a safe and simple technique to extend the usefulness of carbidopa/ L-dopa therapy in advanced Parkinsonís disease. Patients should make sure that the levodopa should be taken at least 30 minutes before meals; if there is need to eat snacks between meals, choose those with little or no protein like fruit, juices, etc.
This plan advocates restricting protein intake to 7 Ė 10 g during the day in order to maximize absorption of the drug and minimize motor fluctuations. It also advocates consuming most of the protein in the evening when poorer motor functions are less likely to disrupt a personís lifestyle. This plan is well tolerated by most but is not ideal, because mobility is greatly reduced during the nighttime, and many people find they have difficulty turning in bed, or getting up at night. Some people then forego eating any protein in the evening, so as to have better control of Parkinsonís disease symptoms throughout the night; such deprivation leads to protein starvation and illness, and even hospitalization. Thus, good motivation, and dietetic education and support should be given while prescribing this diet plan.
► Carbohydrate intake in Parkinsonís disease: High-carbohydrate (high-carb) plan is recommended to people with Parkinsonís disease. A person with the disease should eat meals that consist of a ratio of five-to-seven parts carbohydrate to one part protein (5:1 to 7:1). Carbohydrates are broken down into glucose and proteins are broken down into amino acids where they enter the blood stream. A high proportion of carbohydrate to protein causes release of large amount of insulin hormone, which removes specific amino acids from the blood stream and lowers the competitive interaction between amino acids and Sinemet (a medication to treat Parkinsonís disease which is a combination of levodopa and carbidopa). The high-carb meal plan appears to work well for about two-thirds of the people who try it.
► Fluid regulation in Parkinsonís disease: Patients with Parkinsonís disease are more likely to have constipation. In these patients disease, fluid is one of the most neglected nutrients.
Benefits of having adequate fluids in the diet-
► Fluids help relieve constipation: Fluids help relieve constipation. If fluid intake is less, start gradually adding half-glass a day, and work up to 6 to 8 glasses. Fruits juices, butter milk, coconut water, and soups should be included in the diet to maintain hydration.
► Urinary tract infections: Bladder and urinary tract infections are common in older adults and people with Parkinsonís disease as the thirst sensation is blunted in them. Therefore, patients with Parkinsonís disease don''t feel thirsty, even when fluids are needed. Elderly people have a tendency to get into state of dehydration for longer periods which allows bacteria to grow and multiply in the bladder and urinary tract causing infections. Therefore, adequate fluid intake should be maintained. Another good remedy to ward off urinary infection is use of cranberry juice.
► Dry mouth, dry eyes, and thirst: There are more reasons for adequate fluid intake. Some people report that they often feel thirsty and sometimes have dry mouth, thick or sticky saliva, and dry eyes. Dry mouth may also be caused by difficulty with swallowing, sleeping with the mouth open, or mouth breathing while awake. Various reflexes are deteriorated in patients with Parkinsonís disease including the blinking reflex, resulting in less frequent blinking in the individual patient. This makes the eyes tired, dry and itchy even when person is on adequate amount of water. Acute thirst can be a sign of severe dehydration, which can even lead to death.
► High Fiber Diet in Parkinsonís disease: The diet should be high in fiber and fluids to avoid constipation that is often caused by medications for Parkinsonís disease. Laxatives stimulate the nerve endings of the colon, causing rapid removal of bowel contents. Over time, stimulant laxatives damage the lining of the colon, causing even greater difficulty with constipation. Therefore, consumption of laxatives should be avoided. Both soluble and insoluble form of carbohydrates should be included in the diet. Whole grains, pulses, fruits and vegetables with edible skin should be included in the diet. Fiber intake should range from 25 to 35 g/ day. Fluids are as important as fibers as without fluids, fiber particles remain dry and harden which leads to constipation. Ten to twelve glasses of liquid intake should be aimed for.
► Other nutrients and Parkinsonís disease-
Vitamin B6: It was observed that vitamin B-6 hampers the absorption of levodopa; so patients with Parkinsonís disease are advised to refrain from foods rich in vitamin B-6.
Antioxidants: It has been suggested that high dietary intakes of antioxidants may be protective against the development and progression of the disease. A study showed that higher intakes of vitamin E which is an antioxidant had protective effect against Parkinsonís disease whereas higher consumption of ‚-carotene did not make a significant change in the risk of developing Parkinsonís disease
Aspartame: Some studies showed that that aspartame consumption in amounts well in excess of what would be consumed by heavy users of aspartame-sweetened products has no adverse effect on Parkinsonís disease patients. Thus, aspartame may be used by these patients with diabetes.
Management of Conditions associated with Parkinsonís Disease-
Various conditions are associated with Parkinsonís disease, which needs a well-planned management of diet to control them.
► Constipation and Parkinsonís disease: Constipation is very common in patients with Parkinsonís disease. The major reasons for constipation are degeneration of the nerves of the digestive tract which control the rhythmic movements called peristalsis. Slow peristalsis of the colon indicates that the stool moves slowly and becomes hard and dry causing constipation. Also, medications used to treat Parkinsonís disease can also cause constipation. People with Parkinsonís disease often have a craving for sweets, which causes constipation by replacing the high-fiber foods that help to soften the stool and speed peristalsis. Very few people drink enough fluids, which are needed to help keep the stool soft and bulky.
Therefore, the patient should train himself to ďhonor the urgeĒ to have a bowel movement. Alterations in height of the toilet seat may help in movement and mobility but are not very ideal for emptying reflex. Raising oneís feet may help them to evacuate.
► Bone health and Parkinsonís disease: Men with Parkinsonís disease are especially at a risk for osteoporosis and fractures. Studies have shown that both men and women with Parkinsonís disease are likely to have lower bone mineral density, and greater incidence of osteoporosis, falls and bone fractures. Recovery from hip fracture takes longer in patients with Parkinsonís disease, and many people require long-term care before returning to their own home.
Patients should consume a diet high in calcium and include high-calcium sources such as milk and milk products, dark green leafy vegetables, and sesame seeds in their diets. Vitamin D is another important vitamin for bone development. Therefore, exposure to sun may be necessary or vitamin D supplements may be taken. Magnesium and vitamin K-rich diets should be consumed as they are important nutrients for bone health.
► Unintended Weight Loss and Parkinsonís disease: All too often, people with Parkinsonís disease lose weight, sometimes a critical amount of weight, unintentionally. The possible reason for it can be depression which can cause lack of appetite and reduces desire to eat. Patients sometimes take long hours to eat one meal as they face some chewing and swallowing difficulties. Also, some have difficulty manipulating a fork and knife. Tremor and dyskinesia in addition burn up many extra calories. In other instances, people with Parkinsonís disease report their appetites are good, they enjoy eating, and yet still mysteriously lose weight.
Various methods to resolve problems related to unintentional weight loss-
► Loss of taste and smell: Patients with Parkinsonís disease often lose the sense of smell and taste and this affects their appetite. Such patients should force themselves to eat. Well-balanced and spaced-out meals should be planned for them. If weight loss has already occurred, calories should be adequate to allow to regain weight.
► Inability to finish meals at time: Several conditions may make it hard to finish a meal. Sometimes bradykinesia (slowed movement) makes it difficult to handle utensils. A person with Parkinsonís disease should avoid raw vegetables and lettuce salads. Mechanically altered food like vegetable juices, cooked vegetable and soups could be a better choice.
► Difficulty in swallowing: If itís hard to swallow, or if choking occurs, a speech pathologist should be consulted. The speech pathologist can perform a swallowing test and teach swallowing techniques.
► Weight loss due to depression: Many a times, weight loss occurs due to depression where the patient is in state of hopelessness; such cases are referred to counselors.
Special Tips for the Parkinsonís Disease Patients-
Some special dietary changes work well in improving the condition of patients of Parkinsonís disease.
► Keep on hand the foods you like best. Itís easier to eat foods you like than those you donít much care about.
► Various snacks like soya puffs, roasted snacks, cookies, and ice creams can be included in the diet at frequent intervals.
► Variety is important; different colored meals are more appealing. Different gestures, cheerful setting and pleasing music can be of help.
► Diet for Parkinsonís disease patient should be tailor made. It should depend on the co-existing co-morbidities like constipation, weight loss, or other disease like diabetes, hypertension etc.
► Snacks between meals are an excellent choice for the patient as they help to control blood glucose. Also, they can help you to regain weight. Three small meals, along with frequent snacks daily can add the extra calories needed to gain weight. Snacks can help prevent heartburn and help fight fatigue.
► High protein food should be taken in moderation. Plant protein (dried beans, nuts, and seeds) contains a high ratio of carbohydrates to protein, whereas meat, fish, and poultry contain no carbohydrate.