According to prevalence studies, Parkinson's disease (PD), which is seen in approximately 0.3-1% of the population over the age of 65 worldwide, has a prevalence of 0.3% in the population over 15 years of age in Turkey, while the prevalence in individuals over 65 years of age is 2%. To raise awareness and highlight Parkinson's disease’s burden, World Parkinson's Day is celebrated globally every year on April 11th, in honor of the birthday of the English doctor James Parkinson, who first described the disease in 1817.
Parkinson's disease (PD) is a progressive, neurodegenerative, and chronic condition caused by the loss of dopamine-producing cells in the brain, particularly in the basal ganglia, including the substantia nigra pars compacta, substantia nigra pars reticulata, and pigment cells in the brainstem, as well as cells in the hypothalamic arcuate nucleus and pineal glands. This leads to a decrease in dopamine levels or defective dopamine synthesis. PD is characterized by tremors, rigidity, bradykinesia (slow movement), and postural reflex abnormalities. It typically starts between the ages of 45 and 65 and progresses gradually throughout ranging between 10 to 20 years. A hallmark distinguishing PD from other neurodegenerative diseases is the asymmetry of muscle involvement and the presence of tremor at rest.
Phenylalanine (Phe), an essential amino acid, is hydroxylated to form the non-essential amino acid tyrosine, which then undergoes a second hydroxylation reaction to convert to L-dopa in the presence of the coenzyme tetrahydrobiopterin. L-Dopa, a molecule capable of crossing the blood-brain barrier, is decarboxylated to form dopamine, which is unable to cross the blood-brain barrier itself. Due to the restriction of dopamine's ability to cross the blood-brain barrier, the brain tissue becomes dependent on its production of dopamine. In this context, dopamine replacement therapy using L-dopa drugs, which is considered to be the gold standard, helps distinguish PD from other neurodegenerative diseases due to the acute response to L-dopa.
Pathophysiological studies have shown that mitochondrial dysfunction in the brain, which is responsible for high-energy demand, leads to impaired energy production. This, along with oxidative stress caused by the release of superoxide and increased free radicals, results in lipid damage. Lipid damage in brain cell membranes leads to chronic inflammation in cells, the accumulation of inflammatory biomolecules, and a decrease in proteasomal activity, which impairs protein clearance, and eventually causes the accumulation of defective proteins (mostly α-synuclein). The excessive release of glutamine and its conversion to glutamate, which leads to excitotoxicity in neurons, is linked to calcium influx through N-Methyl-D-Aspartate receptors and calcium accumulation in the brain, which leads cells to necrosis.
Genetic susceptibility related to mutations in genes such as SNCA, LRRK2, and PINK1 has been studied, as well as the dominant and recessive nature of these mutations. Furthermore, studies have been conducted to explore the multifactorial foundations of Parkinson's disease related to the accumulation of heavy metals and pesticides. Recent research highlights the role of mitochondrial dysfunction and the alteration of gut microbiota to reduce oxidative stress, as well as histopathological studies showing the accumulation of α-synuclein protein in the brain tissue through the vagus nerve after being absorbed in the intestine.
To alleviate symptoms and increase L-Dopa levels, dietary recommendations should take into account the individual's age, medication use, and overall condition, including factors such as dysphagia and constipation. Foods rich in L-Dopa, such as fava beans, bananas, and avocados; sources of tyrosine, such as chicken, turkey, eggs, almonds, hazelnuts, and pumpkin seeds; and sources of phenylalanine, such as dairy products, meat, fish, and soybeans, are recommended. A diet rich in antioxidants, such as vitamin C (found in citrus fruits, peppers, strawberries, broccoli), vitamin E (found in olive oil, spinach), carotenoids (especially beta-carotene), coenzyme Q10 (found in salmon, tuna, hazelnuts, spinach), and B6, B9, and B12 vitamins is also advised. Additionally, probiotics such as yogurt, kefir, sauerkraut, and kimchi, as well as prebiotics like garlic, onions, leeks, bananas, and asparagus, are recommended. It is also advised to avoid processed foods containing monosodium glutamate to limit glutamate intake and prevent the accumulation of α-synuclein.
In 2021, the American Physical Therapy Association published a Clinical Practice Guideline for Parkinson's Disease Management, which included recommendations for improving balance and coordination issues faced by patients. The guideline emphasizes exercises to improve posture control and their appropriate frequency and intensity.
Without health policies and care models adopted by society to support healthy aging, approaches focused solely on nutrition and exercise will not be sustainable in the long run. Therefore, the development of general health policies has become important. In this context, social policies and social services have gained more focus, and the multi-layered socio-economic elements related to the disease (such as early diagnosis and treatment costs, medication expenses, home care fees, training of caregivers, and support needs) should be made visible to the public. As such, public awareness on these matters on April 11th has gained significance.
On this day, seminars, awareness campaigns, and support events are held globally to raise awareness about the disease, emphasizing the importance of early diagnosis, and supporting both patients and caregivers.
