Like many devastating modern diseases, the exact cause of Parkinson’s remains a mystery. 1 It affects 1% of the population over 60-years-old and is characterized by tremors, stiff muscles, and loss of balance that gets progressively worse. 2
How does Parkinson’s Disease affect the brain?
Dopamine is made in the brain by cells called substantia nigra. This brain chemical plays in important role in movement by sending a signal from the brain to the body via the central nervous system.
In a person with Parkinson’s, substantial nigra cells begin to die. Thus, less dopamine is produced in the brain affecting movement. As the disease progresses, more cells die and dopamine continues to be reduced.3 5
What causes Parkinson’s Disease?
Although researchers have not found an “exact” cause for Parkinson’s, they believe that genetic and environmental factors are to blame. The Michael J. Fox Foundation for Parkinson’s Research explains:
The exact cause of Parkinson’s disease is unknown, although research points to a combination of geneticand environmental factors. If a continuum existed, with exclusively genetic causes at one end and exclusively environmental causes at the other, different Parkinson’s patients would likely fall at many different places along that continuum…
Scientists currently believe that in the majority of cases, genetic and environmental factors interact to cause Parkinson’s disease.The Michael J. Fox Foundation for Parkinson’s Research
Environmental Factors Linked to Parkinson’s
We live in a toxic environment. We are surrounded by chemicals. Reducing our exposure is the most important way we can protect our health.
New research has found a link between Parkinson’s and the low amounts of the herbicide paraquat. 6 Paraquat is one of the most widely used chemicals in the US. For example, it is used to defoliate cotton before harvest. According to the United States Environmental Protection Agency, “Paraquat is highly toxic to humans. One small sip can be fatal and there is no antidote.” There have been three deaths from the herbicide having mere contact with workers’ skin or eyes. 7
Paraquat has been used in the Drug War to kill cannabis plants during the Reagan administration. 8 9 Despite knowing the how dangerous the herbicide was and that some of the toxic pot was making it into the black market, the government continued to use it in the US and Mexico.
Paraquat has been banned in the European Union and China. It is currently undergoing its 15-year review by the EPA.
The link between paraquat and Parkinson’s has been theorized in the past, and there have been lawsuits.10 Prior research has concluded the link is “rather limited and based on insufficient epidemiological data”. 11
Researchers have not given up on finding a relationship between paraquat and Parkinson’s. In an article published September 2018 edition of the Nature Partner Journal Parkinson’s Disease, researchers recreated the disease in rats using low amounts of paraquat and the food protein lectin.
Increasing evidence suggests that environmental neurotoxicants or misfolded α-synuclein generated by such neurotoxicants are transported from the gastrointestinal tract to the central nervous system via the vagus nerve, triggering degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and causing Parkinson’s disease (PD). We tested the hypothesis that gastric co-administration of subthreshold doses of lectins and paraquat can recreate the pathology and behavioral manifestations of PD in rats. A solution containing paraquat + lectin was administered daily for 7 days via gastric gavage, followed by testing for Parkinsonian behavior and gastric dysmotility.Ingestion of subthreshold doses of environmental toxins induces ascending Parkinsonism in the rat
What makes this study different than other that have found a connection between Parkinson’s and paraquat is that researchers discovered the pathway in relation to the gut.
Two weeks after co-administration of paraquat and lectin for seven days, Alberto Travagli and colleagues at Penn State College of Medicine, Pennsylvania, found misfolded α-synuclein in both the vagal neurocircuitry, which connects the gastrointestinal tract to the central nervous system, and the substantia nigra pars compacta where there was also a loss of dopaminergic neurons. Furthermore, the rats exhibited typical PD symptoms, including reduced gastric motility and impaired motor function, that could be alleviated with L-dopa. Removing part of the vagus nerve prevented the development of disease suggesting that environmentally triggered PD spreads from the gutIngestion of subthreshold doses of environmental toxins induces ascending Parkinsonism in the rat
It was the combination of lectin and paraquat that led to the creation of the disease in rats. Lectins are proteins that bind to carbohydrates like sugar. This protein is found in both plant and animal-based foods. It passes through our bodies undigested. Food high in lectin are soybeans, tomatoes, potatoes, and wheat. 12
Lectin in large amounts causes irritation and reduce absorption in the gut. They bind to the walls of the intestines and can cause leaky gut. Cooking, formenting, and sprouting reduces lectins in food. Lectins do play a role in digestion; however, by slowing down carbohydrate breakdown and thus lowering the glycemic levels of food. 13
Researchers used “subthreshold” doses of both lectin and paraquat. Lectin was included because this protein is pervasive in the human diet throughout the world and may transport from the gut to the nervous system pathogens and toxins. They explain:
Lectins are ubiquitous carbohydrate-binding proteins that are present worldwide in the human diet.26 Lectins can penetrate the GI tract, either by endocytosis, via a breakdown in gut barrier function, or via a lectin receptor (saccharide)-mediated mechanism, and can be transported retrogradely within neurons.27,28,29,30 While lectins are environmentally pervasive, dietary lectins in properly cooked food are harmless and generally thought to pose no health risk.26 The consumption of raw uncooked vegetables, grains, and eggs that are rich in lectins, however, can potentially enhance the toxicity of pesticides and herbicides resulting in higher prevalence of idiopathic PD.17 By virtue of their membrane permeability, lectins have been developed as a chaperones for drugs, but have also been shown to transport viruses and toxin(s),31,32including those that may be responsible for α-synuclein inclusions in PD.33 As such, a lectin-mediated insult is likely to be gradual, and may be influenced by association with other macro/micronutrients or ingested chemicals. It is possible, therefore, that dietary lectins contribute to the transport from the GI tract to the central nervous system (CNS) of pathogens that induce degeneration of dopaminergic neurons and Lewy body-like protein aggregation, i.e., the histological hallmark of idiopathic PD.34 Thus, lectins may represent a key environmental factor in the development of this disease.Ingestion of subthreshold doses of environmental toxins induces ascending Parkinsonism in the rat
The gut connection to Parkinson’s disease was discovered two years ago. In a different study not involving paraquat, scientists found “a functional link between the bacteria in the gut and the onset of Parkinson’s disease”. Three experiments were done on mice. What they discovered was that the kind of gut bacteria present has an effect on the disease. 14
Our GI Tract is often called our “second brain“. Gut bacteria is important for mental health and disease prevention. As researchers know, it is the pathway to our nervous system for toxins and pathogens.
Toxic pesticides like paraquat should not be legal. This research should be enough for the EPA to ban it use. Unfortunately, the comment period is closed. You can review the docket here.