Is Parkinson’s Disease a Gut Problem?

Article overview:

• One study found that Parkinson's disease can be triggered by an intestinal protein that accumulates in the appendix.
• Scientists have known about a link between the gut and Parkinson's disease because gastrointestinal problems such as constipation, gas, and nausea often occur in many patients before the signs of Parkinson's disease appear.
• It is important that good bacteria thrive in our gastrointestinal tract, because the more good bacteria you have in your intestines, the less chance bad bacteria and their by-products have of gaining a foothold.

Research on Parkinson's & The Gut

It has long been known that Parkinson's disease is a disease that occurs in the brain. Certain nerve cells in the brain begin to break down and levels of dopamine, a neurotransmitter, drop, causing coordination problems, muscle stiffness, language changes, and the tremors that are the characteristic symptom of the disease. But now there is growing evidence that this brain disorder does not actually start near the brain. New research has linked an organ long believed to be useless to the development of Parkinson's.

The study, conducted at the Van Andel Research Institute in Grand Rapids, Michigan, found that Parkinson's disease can be triggered in at least some people by an intestinal protein that accumulates in the appendix. These results were based on an analysis of the medical records of nearly 1.7 million men and women in the Swedish National Health Database, which dates back to 1964.

The researchers compared the medical history of people diagnosed with Parkinson's disease with records of appendectic removal, and found that people who had surgery to have their appendix removed were 19 percent less likely to get Parkinson's. However, that was not enough information as there were some confusing factors.

Can an appendectomy help?

First, appendicectomy – even decades earlier at a young age – did not eliminate all risk of Parkinson's. it just lowered it. And if they got the disease, those who had their appendix removed this early were more likely to develop Parkinson's symptoms later than their colleagues who held the appendix. In addition, subjects who lived in rural areas appear to have similarly low rates of Parkinson's disease even if their appendix was not removed.

To learn more about the role the appendix might play in the development of Parkinson's disease, the researchers then evaluated samples of appendix tissue taken from 48 people who did not have the disease. They found that a Parkinson's-associated protein, alpha-synuclein – an important part of the Lewy bodies that are an indicator of Parkinson's disease in the brain – was present in as many as 46 of the 48 samples from people without Parkinson's disease. To make matters even more confusing, it was also present in most of the patients diagnosed with the disease, and inflammation of the appendix was irrelevant to the occurrence of the disease.

Hence, it seems that the majority of us have alpha-synuclein stores in our appendix, but the current study does not clarify what could be the trigger affecting the nerve cells of the brain in some people. Scientists were aware that there may be a link between the gut and Parkinson's disease, since gastrointestinal problems such as constipation, gas, and nausea often occur in many patients before signs of Parkinson's disease appear. The results also agree with those of an earlier study conducted in 2017 at Duke University in Durham, North Carolina, which shows that alpha-synuclein is present in intestinal cells that are connected to nerve pathways. There are theories that alpha-synuclein travels from the appendix to the brain via the vagus nerve. But again, we don't know why it might travel with some people and not others.

How the gut microbiome affects our health

Regardless of the exact method of transmission between the nervous system, appendix and intestine, however, we know that the gut microbiome affects our health in many ways. A 2007 study at Duke University Medical Center in Durham, North Carolina uncovered a link between the appendix and beneficial bacteria in the intestinal tract. The appendix contains tissues of the immune system and can serve as a storehouse for beneficial gut bacteria. But perhaps it is home to large populations of harmful bacteria in some people. And in these people, the appendix becomes cluttered and releases harmful alpha-synuclein.

While there are many of these connections that we still don't understand, we know that it is important for good bacteria to thrive in our gastrointestinal tract – first because they are healthy in and of themselves, but also because you are have more good bacteria The fewer opportunities there are for bad bacteria and their by-products to gain a foothold in your gut. And the best way to do this is by eating a healthy, high-fiber diet and supplementing with probiotics. To learn more about their health benefits, check out Jon Barron's article "Probiotics Revisited, Part 1".