What is Parkinson’s Disease?: Causes, Symptoms, and More

When it comes to neurological disorders, it’s no surprise that Alzheimer’s ranks number one in the number of people it affects. What’s number two? Parkinson’s disease. (5) According to the Parkinson’s Foundation, nearly one million Americans, and ten million people globally, are living with Parkinson’s. This is more than the number of people suffering from multiple sclerosis, muscular dystrophy, and amyotrophic lateral sclerosis (ALS) combined. (43) And cases are on the rise, leading some experts to state that we are approaching a Parkinson’s “pandemic.” (10) In fact, an international group of researchers estimate that cases will double by 2040. (25) While the incidence of Parkinson’s disease is projected to increase, few people understand the many ways it can impact the lives of people with the condition. 

Did you know? Men are 1.5 times more likely than women to develop Parkinson’s disease. (4)(43)

What is Parkinson’s disease?

Parkinson’s disease (PD) first gained widespread attention when actor Michael J. Fox went public with his Parkinson’s diagnosis in 1998. Since then, we’ve learned of a surprising number of celebrities with Parkinson’s including Alan Alda, Jesse Jackson, Linda Ronstadt, Neil Diamond, and Ozzy Osbourne. (33) While this has led to some awareness among the general public, most people still don’t fully grasp the complexities of the disease.PD is a progressive neurodegenerative disorder in which certain dopamine-producing cells in a region of the brain called the substantia nigra pars compacta gradually die. (15)(30)(44) Dopamine is the “feel good” neurotransmitter responsible for the feelings of pleasure and motivation. But it also plays key roles in cardiovascular health, cognition, digestion, motor control, sleep, and stress management. (6)(22)(41) By the time symptoms occur, about 60% to 70% of these cells are gone. (4)

Developing Parkinson’s disease

The cause of PD is largely unknown, but researchers have several theories that include genetic factors and mutations, mitochondrial dysfunction, and high levels of oxidative stress in the brain. Another popular theory suggests that an unknown pathogen or environmental toxin may be at the root of PD and its effect on movement. (4) PD also causes people to lose nerve endings that produce norepinephrine, the main neurotransmitter that controls a variety of non-movement functions in the body. Although the cause of this loss remains elusive, it may explain some of the other symptoms in PD such as fatigue, irregular blood pressure (e.g., low blood pressure upon standing), and digestive problems. (34) 

Whatever the cause, scientists have identified a number of risk factors that may increase the odds of developing PD. These include: 

• Being over the age of 50 (4)
• Consumption of dairy products (3)
• Family history (38)
• History of melanoma (3)
• Pesticide exposure (2)(19)
• Traumatic brain injury (3) 

Did you know? Exposure to some pesticides like paraquat, rotenone, and organochlorines appear to be strongly linked to the development of PD. (29)

Parkinson’s symptoms 

Tremors (involuntary movements) may be the first thing you notice about someone suffering from Parkinson’s. But shaking isn’t the only symptom of PD. According to the Parkinson’s Foundation, other common symptoms and signs of the disorder can include: 

• Balance problems 
• Cognitive changes
• Constipation
• Dizziness
• Drooling
• Excessive sweating
• Fainting
• Feeling full after eating small amounts
• Loss of smell
• Masked or serious facial expression
• Muscle rigidity 
• Mood disorders
• Pain 
• Sexual dysfunction 
• Shuffling gait
• Sleep problems
• Slouching or hunching over
• Small handwriting
• Soft or low voice
• Stiffness in the body
• Vision problems
• Weight loss (1)(27)(32)

The 5 stages of Parkinson’s disease

People living with PD typically move through five different stages, each more severe than the previous stage. 

Stage 1

During this stage, mild symptoms occur including changes in posture or walking, alterations in facial expressions, tremors and other movement symptoms on one side of the body only. At this stage, symptoms don’t interfere with daily life. (42)

Stage 2

Symptoms worsen and tremors now affect both sides of the body. The person can live independently, but accomplishing everyday tasks becomes more difficult. (42)

Stage 3

Movements become slower and balance becomes more challenging, increasing the risk of falling. Being able to independently complete tasks like dressing and eating also becomes harder. (42)

Stage 4

As the disease progresses to stage 4, motor symptoms become more severe and the person likely needs help with everyday activities. A walker may be required. (42)

Stage 5

This is the most advanced stage. Because stiffness in the legs can make it impossible to stand a walk, the person with Stage 5 PD likely will either require a wheelchair or become bedridden. They may also experience hallucinations. Full-time care is required at this stage. (42)

Can you prevent Parkinson’s disease?

Unfortunately, there are no proven ways to prevent PD. That said, there are a few lifestyle changes that may reduce your risk. Moderate- to high-intensity exercise has been shown to lower the risk of developing PD and may help delay symptoms and improve the quality of life in those who already have the disorder. (8)(14) According to findings in the journal Oxidative Medicine and Cellular Longevity, physical activities like dancing, martial arts, running, weight lifting, and yoga are especially effective for prevention. (11) Among those who have been diagnosed with the disorder, regular physical activity may also improve motor symptoms like shaking or gait, cognitive issues, fatigue, mood disturbances, PD-related pain, and sleep disorders. (46) 

Other research suggests that avoiding agricultural chemicals as well as sources of other environmental factors like air pollution, heavy metals, and organic solvents may help prevent or delay the onset of PD. (9) Cleaning up your personal environment by choosing organic food when possible and opting for nontoxic household and personal care products may be a good place to start.

Eat a balanced diet 

Diet may also play a role in PD. Studies show that a high intake of some foods—especially low-fat dairy foods—may increase the risk of PD. (17) On the flip side, the type of diet you eat may help prevent PD and support better outcomes in those with the disorder.

According to a recent study published in the journal Movement Disorders, Canadian researchers found that both the Mediterranean diet and the MIND diet were linked to a later onset of PD—up to 17.4 years later. (26) Both of these diets are rich in antioxidants and omega-3 fatty acids. (18)(24)

Other investigations pinpoint several specific foods that may help prevent PD. In a review of 12 studies at the City University of New York School of Public Health, coffee and black tea appeared to be protective due to their caffeine content. (12)(36) This could be because caffeine can help to prevent the loss of dopamine. (35)

Other foods that may help offer a protective effect against PD include vegetables in the nightshade family like peppers. (12) These foods are high in nicotine, which has been found to protect neurons. (31)

The type of fat you eat may also play a role in prevention. Research suggests that higher amounts of dietary cholesterol, which is found in cheese, egg yolks, and meat, seems to confer some protection for men, but not women. Women, on the other hand, appear to gain protection from monounsaturated fats like those found in avocados, nuts, and olive oil. (12)

4 supplements for Parkinson’s disease 

In addition to partaking in regular physical activity and eating an antioxidant-rich diet, there’s some evidence that the following nutrients, when taken as supplements, may help reduce your risk for PD. 

1. Coenzyme Q10

This nutrient, which is naturally produced by the body, generates cellular energy and acts as an antioxidant. (7) Some preliminary studies suggest that supplemental coenzyme Q10 (CoQ10) may help prevent the onset of PD by protecting neurons from toxicity and reducing the loss of dopamine in the brain. (40)(13)

In one placebo controlled human trial involving 80 PD patients, researchers at the University of California, San Diego, found that doses as high as 1,200 mg safely slowed the progression and functional deterioration of the disorder. (39)

2. Curcumin

This compound, which is found in the spice turmeric, is best known for its anti-inflammatory properties. (21) However, studies report that, because curcumin can cross the blood-brain barrier, it also boasts antioxidant and neuroprotective benefits. (28) One review of 13 animal studies that appeared in BMC Complementary Medicine and Therapies found that curcumin protected substantia nigra neurons and this, in turn, helped to support healthy dopamine levels. (45)

3. Vitamin C

Research suggests that there may be a link between vitamin C and dopamine levels. During one lab experiment using human nerve cells, German scientists found that vitamin C increased the production of both levodopa (a precursor to dopamine) and dopamine. (37)

Vitamin C may not just help those with PD, it may also help prevent the disorder. After reviewing data from two large studies, researchers at Harvard found that this nutrient reduced the risk of PD. However, due to a gap in the data, they noted that further study is needed. (16)

4. Vitamin D

The sunshine vitamin may help provide protection to neurons thanks to the role it plays in autophagy (the body’s process of removing old or damaged cellular material). (20) Some evidence notes that higher vitamin D levels are linked to a decreased risk of developing Parkinson’s disease, (23) while low levels of this critical nutrient can increase risk. (47)

The bottom line

Parkinson’s disease is a progressive disease that affects movement and cognition. Currently, there is no cure for PD and no foolproof way to prevent the condition. However, some research suggests that physical activity, a healthy diet, and targeted supplements with antioxidant and anti-inflammatory properties may reduce the risk. If you have a family history or have early signs of PD, it’s wise to consult your healthcare practitioner.