This article contains extracts of the book Our Daily Poison, from Marie-Monique Robin. 

Parkinson’s disease is the 2nd most common neurodegenerative disease (after Alzheimer’s disease) and it has been estimated that nearly 1 million people are currently diagnosed, with over 60’000 new cases each year. It was first described by an English doctor, James Parkinson, in his “Essay on the Shaking Palsy” in 1817. First very uncommon, it has became lately more prevalent among elderly people, and has brought more awareness since celebrities such as Michael J Fox, Muhammad Ali, George Bush senior, or more recently Robin Willams have been diagnosed with it. Parkinson’s disease is commonly known by the medical world to be idiopathic (no known causes) and has no cure. But those two statements are very questionable.

What is Parkinson’s disease?

Parkinson’s disease is a disease that cause early degeneration of a part of the brain called substantia nigra (“black substance” in Latin). The main function of the cells located in the substantia nigra is to produce a neurotransmitter called Dopamine, which plays a huge role in the initiation and inhibition of movement and thoughts. For this reason, most of the symptoms of Parkinson’s disease will involve motor function. The four main symptoms of Parkinson’s disease are:

  • Bradykinesia (slowness of movement)
  • Tremor (or shakiness)
  • Limb rigidity
  • Gait and balance issues

Although people don’t die from it, Parkinson’s disease can lead to severe complications that can be fatal. Now the question is, why is there more and more people diagnosed with Parkinson’s disease? Is it because we live longer and hence have more chance to develop neurodegenerative diseases? Maybe, however it is important to underline that Parkinson’s disease is not an “old people disease”.

 

Toxins as an important factor of Parkinson’s disease: A few examples

Even though he didn’t give any explanation in his essay of the cause the disease, James Parkinson suggested that it has environmental triggers. Early in the 20th century, clinicians noted that exposure to Manganese dust would trigger Parkinson-like symptoms in miners. A recent study showed that manganese would cause death of some neurons, leading to decrease in production of dopamine. In 1988, a study showed that farmers using Maneb, a fungicide that contains manganese, would present with Parkinson-like symptoms.

Parkinson’s disease has also suddenly appeared at a high rate in the street of San Francisco among young drug users. Doctors noticed that a synthetic type of heroine called MPPP would trigger Parkinson’s. MPPP contained a contaminant, called MPTP, wich is structurally very similar to some herbicides that are still used today(!).

In Guam, researchers noticed a much higher rate of the disease among the aboriginal Chamorro population. So much higher than everywhere else that it even has its own name: Lytico-Bodig disease. Scientific analyses measured on those aborigines high level of a toxin called BMAA (beta-methylamino-l-alanine). Chamorros would ingest this toxin in the form of flour coming from palm tree seeds. Later on, researchers found out that the aborigines would also eat bats, which ate a lot of those seeds and the BMAA toxin would accumulate in the bat’s tissues. The extinction of those bats coincided with the decrease in prevalence of Lytico-Bodig disease in Guam.

Similarily, a study among male twins was conducted in Hawaii. One twin had Parkinson’s disease and the other did not. One of the risk factor was higher consumption of milk, which is suspected to contain persistent organic pollutants such as PCB (polychlorinated bisphenyls). 

So why are we so sensitive to pesticides? David Pimentel, professor at the College of Agriculture and Life Science at Cornell explained that:

” Less than 0.1% of pesticides applied for pest control reach their target pests. Thus, more than 99.9% of pesticides used move into the environment where they adversely affect public health and benficial biota, and contaminate soil, water, and the atmosphere of the ecosytem.”

 

Early signs

Although tremor is one of the most common sign of Parkinson’s disease, it usually comes several years after the process started. There are earlier and more subtle signs that suggest possible early Parkinson’s disease. All of those signs can also be explained by more benign health issues, so make sure to consult a doctor before self-diagnosing.

  • Loss of smell: And not because of a stuffy nose, but a consistent decreased sense of smell that can identify with food for instance.
  • Constipation: Parkinson is a movement disorder and bowel movements will hence be affected as well. Again this not apply if this is due to lack of fibers in diet, medication side-effects,…
  • Frozen shoulder: It is an umbrella of multiple conditions that causes restricted motion of the shoulder, and therefore can have multiple causes. However, if everything else has been ruled out by your doctor and if it fits the clinical picture, it can potentially be an early sign of Parkinson’s disease.
  • Change in hand writing: Small, fine movement will be affected first and people with Parkinson’s disease will show a smaller, shakier writing than they used to have.
  • Low tone voice: The decrease in dopamine production will affect how your voice will sound.
  • Masked face and decreased eye blinking frequency: We normally blinks at least every 10 seconds. Absence of blinking for a longer period can be an early sign.
  • Change in gait and posture: The gait will usually gets slower and the body more hunched over.

 

Treatment

There is no standard treatment for Parkinson’s disease. Treatment usually include medication (Levodopa, dopamine agonists, MAO-B inhibitors) or surgery. Lately new techniques have been discovered to palliate some of the symptoms such as Deep Brain Stimulation. However, finding a potential environmental cause of the trigger of Parkinson’s disease might offer hope.