People with Parkinson’s disease have a much higher incidence of stomach ulcers, which occur years before the onset of the disease. H. pylori infection is the main cause of stomach ulcers.

One study found that having an H. pylori infection increases a person’s risk of Parkinson’s 23 to 45 percent, and that treating the H. pylori in people with Parkinson’s can often significantly improve symptoms.

I have written before that H. pylori can enter the bloodstream and trigger generalized inflammation. Such generalized inflammation can activate microglia in the brain, predominately in areas related to Parkinson’s and Alzheimer’s diseases.

It has been shown that having an H. pylori infection can make the neurological symptoms and signs much worse.

Overgrowth of other infectious organisms in the colon has also been associated with an increased risk of Parkinson’s disease. These include certain forms of mycobacteria and Enterobacteriaceae.

In fact, the specific types of Parkinson’s symptoms can be related to each of the types of bacterial overgrowth in the colon, with Enterobacteriaceae being more common in cases of Parkinson’s with postural instability (poor balance) rather than tremor.

A study of 72 Parkinson’s patients compared to 72 normal control patients demonstrated a 77 percent decrease in the number of Prevotellaceae bacteria in the Parkinson’s patients.

This bacteria protects the lining of the intestines by stimulating the production of butyrate.

It is also interesting that several of the genetic links to Parkinson’s risk indicate that the genes involved when mutated, allow these harmful organisms to persist in the body rather than the genes being directly involved in the pathological process.