First discovered in 1815, Parkinson’s disease is currently the fastest growing neurological disorder. In its early stages it is characterised by rigidity, shaking and slowness of movement and speech. After typically 10-15 years these symptoms progress towards dementia.
To put this in the context, Alzheimer’s is the most common form of dementia, followed by vascular dementia, then Lewy body dementia and in 4th position Parkinson’s. Smoking and coffee drinking reduce the risk. Pesticides, solvents and heavy metals increase the risk.
What happens to the brain in Parkinson’s?
Your brain is surrounded by a thin layer of cortex, which is responsible for most of the higher functions that animals like us perform. A large part of the cortex is devoted to the voluntary control of movement and is called the motor and pre motor cortex. However these areas do not work on their own and rely on various other brain areas to modulate and route their messages. One of these areas, located in the centre of your brain is called the basal ganglia. The basal ganglia control voluntary body movements along with your motor cortex.
In Parkinson’s it is the basal ganglia which are most affected. One of the lower components of the basal ganglia, called the substantia nigra (black substance) contains many nerve cells that release the inhibitory neurotransmitter dopamine. This area is badly affected in Parkinson’s leading to the loss of dopamine releasing cells. This results in a loss of movement inhibition leading to the characteristic shaking of Parkinson’s. Dopamine is also associated with feelings of reward and loss of this leads to depression in many cases of Parkinson’s.
Two other common symptoms of Parkinson's and indeed other degenerative diseases such as Alzheimer's is loss of smell, medically called anosmia and constipation. These symptoms can present themselves many years, often decades before the classic symptoms of Parkinson's appear. Indeed there is evidence that the disease actually starts in the gut, with abnormal clumping of proteins called alpha-synucleins in neurons many years before it reaches the brain.
The root causes of Parkinson's
Officially there is no known cause for Parkinson's although there are known to be genetic markers that make it more likely that someone will be affected as they age. There are also important environmental factors that lie behind the rise in rates of Parkinson's over the last 100 years or so.
One of the most recent findings that could lie behind most cases of Parkinson's is the gut-brain linkage, whereby damage that occurs in the gut changes the structure of proteins called alpha-synucleins. Alpha-synuclein proteins normally help bind vesicles full of neurotransmitters to membranes at the end of nerves in order to facilitate communication between nerves.
In Parkinson's it appears that alpha-synuclein proteins get damaged and start clumping together rather than with secretory vesicles. The type of bacteria that you have in your gut could play a large role in determining whether this abnormal clumping starts to take place. In particular inflammatory bacteria produce chemicals that can damage the alpha synuclein proteins and so the more anti-inflammatory types of bacteria you can encourage to grow in your gut the better.
The main nervous connection between the gut and brain is the vagus nerve and it is thought that the abnormal clumping alpha-synuclein particles travel very slowly up neurons within the vagus nerve towards the brain.
How do I reduce my risk of Parkinson's?
There are some key ways to reduce your risk of Parkinson's
- Swap standard fruit and vegetables for organic ones. In the case of Parkinson's some commonly used pesticides and herbicides have been linked to the disease.
- Eat plenty of the types of food called fermentable fibres. These include sweet potatoes, parsnips, celeriac, swedes, beetroot, lentils and oats. These types of food encourage more anti-inflammatory bacteria to grow in your intestines.
- There are a number of other foods that are associated with a lower risk and/or slower progression of the disease. These include fish, olive oil and coconut oil as well as most fresh herbs and spices.
- Get out in the sun to increase your vitamin D levels. Vitamin D receptors are present in the neurons in your brain that are affected by Parkinson's and vitamin D helps neurons to remain healthy by reducing autoimmunity and allowing neurons to develop.
- Check your iron levels are not too high. A high level of iron in the blood worsens outcomes with Parkinson’s and high iron levels have been found in the brains of some Parkinson’s patients. Vitamin C and alcohol could worsen this. Phlebotomy (donating blood) should help.
- Cutting down on gluten (bread, pasta, cakes, most packaged foods) may help up to one third of people with Parkinson's. Both celiacs and those who have non celiac gluten sensitivity NCGS have more tTG6, a transglutaminase enzyme present in the brain. The attack on tTG6 by the immune system leads to neuro-degeneration.
- Avoid excess sugar, which damages proteins in the brain. Insulin resistance, a precursor to diabetes, is a potential causative factor.
- Stress can raise cortisol levels leading to disruption of the circadian rhythm. Bad sleep habits with evening blue light can also cause circadian disruption potentially worsening symptoms of Parkinson's.
- Pesticide exposure has been associated with poor smell in farmers 10-20 years later. In particular DDT and Lindane exposure was tested. Organochlorines such as DDT, insecticides such as Rotenone, herbicides such as Paraquat and fungicides such as Maneb have all been implicated in raising the risk of Parkinson’s. This is partly mediated by oxidative stress. Another toxin to be aware of is Trichloroethylene a solvent found under the Google HQ! Toxic mould and air pollution can both also contribute to the sort of inflammation and oxidative damage that are associated with Parkinson’s.
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