Parkinson’s disease. The link between the disease and the gut

Scientists have discovered additional evidence which links the neurodegenerative disease to the gastrointestinal tract, opening new possibilities for treatment.


For many decades, research on this disease has concentrated on the brain. Scientists initially focused on the loss of neurons that produce dopamine, a molecule involved in many functions, including movement. The gut-brain axis is a bidirectional communication system between the gastrointestinal tract and central nervous system.

New Research on Parkinson’s disease

More recently, it became known that people with PD have different gut bacteria to other healthy adults. Scientists have also focused on the accumulations of toxic alpha-synuclein, a protein that takes on an aberrant form in patients with Parkinson’s disease. Currently a new study by Caltech in the US led by Dr Sarkis Mazmanian, in mice, has shown that the toxic alpha-synuclein fibres that build up in the nerve (neuron) endings of PD patients can impact on brain neurons in a matter of weeks.

“We have discovered for the first time a biological link between the gut microbiome (microorganisms found in association with both healthy and diseased humans) and Parkinson’s disease. More generally, this research reveals that a neurodegenerative disease may have its origins in the gut, and not only in the brain as had been previously thought.

– Sarkis Mazmanian, lead researcher at the California Institute of Technology (Caltech).

Thus, new research outcomes propose Parkinson’s disease might actually start in the gut and this might explain why half of the people diagnosed with Parkinson’s complain of constipation and gut-related symptoms prior to their diagnosis and before other symptoms, like first motor-symptoms arise.

The idea that Parkinson’s begins in the gut makes the move toward consideration of how food-based therapies may play a role in minimizing motor and non-motor symptoms in Parkinson’s.

A growing body of evidence supports this hypothesis, but the question of how changes in the intestines drive neurodegeneration in the brain remains unclear and an active area of investigation. Some studies suggest that it is through the vagus nerve that aggregates of alpha synuclein travel from the intestines to the brain (it is like an electrical cable from the stomach and small intestine into the base of the brain). Others suggest that molecules such as bacterial breakdown products stimulate activity along this channel, or that the gut influences the brain through other mechanisms, such as inflammation. Together, however, these findings add to the growing consensus that “even if the pathology [of Parkinson’s] is very much driven by brain abnormalities, it doesn’t mean that the process starts in the brain,” says Michael Schlossmacher, a physician-scientist at the Ottawa Hospital Research Institute.

All research outcomes indicate the gut plays a key role in the development of the disease.

Testing of the gastrointestinal tract at the Swiss Biological Medicine Center

At the Swiss Biological Medicine Center we provide complete diagnostics on the health of the gastrointestinal system, and upon receiving the results, we provide treatment that aims at restoring its function and maintaining its health.