The author presents a groundbreaking theory linking gut microbiota, metabolic changes, and oxidative stress to PD. The theory identifies mucin-degrading gut bacteria as contributors to the disease by releasing harmful metabolites that affect dopamine-producing neurons.

The theory begins with the observation that PD symptoms often manifest years before motor impairments, with early signs including constipation and loss of smell. These symptoms suggest that the disease may originate in the gut. The author connects these early symptoms to an overabundance of certain gut bacteria that degrade mucin, a protective layer in the gut lining.

Mucin-degrading bacteria release galactose, a metabolite that enters the bloodstream and eventually the brain. In the brain, galactose competes with glucose, leading to reduced glucose availability. This imbalance impairs the production of antioxidants, increasing the vulnerability of dopamine-producing neurons to oxidative stress. Over time, this oxidative damage leads to the degeneration of these neurons, resulting in the hallmark motor symptoms of PD.

The author highlights the unique vulnerability of dopamine and norepinephrine-producing neurons to oxidative stress. These neurons produce a pigment called neuromelanin, which makes them more susceptible to oxidative damage. This explains why these specific neurons are predominantly affected in PD.

The theory also addresses the role of other factors, such as iron and oxygen, in exacerbating oxidative stress. Combined with the galactose-glucose imbalance, these factors create a cascade of damage that progressively harms neurons over decades. This long-term process aligns with the delayed onset of PD symptoms.

For potential interventions, the author suggests targeting the gut microbiota. Strategies could include developing antibiotics that selectively eliminate mucin-degrading bacteria or reducing mucin production in the gut. Additionally, neutralizing galactose in the bloodstream could mitigate its harmful effects. These approaches, combined with early detection of gut-related symptoms, could delay or prevent the onset of PD.

In summary, the author’s theory provides a comprehensive explanation of PD, connecting gut bacteria, metabolic changes, and oxidative stress. It offers novel insights into the disease’s progression and highlights actionable strategies for prevention and treatment. This perspective underscores the importance of gut health in understanding and addressing neurodegenerative disorders.