- involuntary shaking
- slow, shuffling movements
- stiffness or rigidity of the muscles
Symptoms don’t usually start before the age of 50. But once they develop they tend to worsen over time. The symptoms are due to a loss of nerve cells in the brain. But, scientists now believe that Parkinson’s disease does not start in the brain, but in the gut.
The gut has its own nervous system, the enteric nervous system. Sometimes referred to as the second brain. The brain and enteric nervous systems developed from the same embryonic tissue. And a link still connect them. In the form of the vagus nerve.
Contrary to what we once thought scientists now know that communication between the gut and the brain is in both directions. This connection is called the gut-brain axis.
This is relevant for people with Parkinson’s disease as they almost all also have other, non-neurological symptoms. For example, over 80% of people with Parkinson’s disease have digestive system problems, especially constipation. In fact, the constipation usually precedes the neurological symptoms by about ten years.
Other symptoms include:
- balance problems
- loss of smell
- urinary incontinence
- swallowing difficulties
Researchers believe that the gut bacteria may have a role in the digestive symptoms. They have discovered that people with Parkinson’s disease have an altered composition of gut bacteria. Not only that, but the balance of the gut bacteria is associated with the severity of the disease. And there is a high prevalence of small intestinal bacterial overgrowth in Parkinson’s disease.
Could it be that Parkinson’s disease is a result of the effect of pathogenic bacteria on the gut nervous system? This is one theory that is gaining support. Since we know that the gut microbiota can influence the gut-brain axis. It may be possible to manipulate the bacterial population with probiotics or prebiotics. Indeed, there are reports that this has a favourable response. Might we at last have a way to prevent or even reverse Parkinson’s disease.