The Gut Microbiome and Neurological Disease

Studies on the impact of the bacteria that live in our guts has exploded in the last 20 years. While most can understand how gut microbes can affect digestion and cause irritable or inflammatory bowel issues, some of the most interesting science of the last decade has looked at how gut bacteria affects our brains.⁣

Dysbiosis is a condition in which the normal bacterial environment has been disrupted. This means that important good bacteria may be deficient as is the case when patients take antibiotics. It can also mean that there is increased growth of pathogenic bacteria like E. Coli.⁣

Gut dysbiosis has been identified in neurological conditions like Alzheimer’s Disease, #parkinsonsdisease #autism as well as psychiatric conditions like depression and anxiety.⁣

Animal models have shown that replacing the gut bacteria of a healthy mouse with the bacteria of a sick human can actually reproduce the symptoms of the person in the mouse! It’s also been demonstrated that placing the healthy microbes of a healthy person can reverse the symptoms in a sick rodent. ⁣

3 mechanisms for gut-brain communication:⁣

1️⃣ 𝗩𝗮𝗴𝘂𝘀 𝗡𝗲𝗿𝘃𝗲 𝗧𝗿𝗮𝗻𝘀𝗺𝗶𝘀𝘀𝗶𝗼𝗻: The vagus nerve is responsible for monitoring the status of the gut. Products of bacterial metabolism can signal the vagus nerve which can alert the brain to pro or anti inflammatory states. ⁣

There are also theories that suggest that some proteins can travel from the gut into the brain via the vagus nerve, which is a proposed mechanism for how Parkinson’s Disease may evolve from the gut.⁣

2️⃣ 𝗜𝗺𝗺𝘂𝗻𝗲 𝗧𝗿𝗮𝗻𝘀𝗺𝗶𝘀𝘀𝗶𝗼𝗻: There’s a constant battle between the immune system and gut bacteria to prevent overgrowth. Good bacteria release products that can temper the immune system and reduce inflammation.⁣

Pathogens can trigger strong immune responses that promote inflammation, especially with a leaky gut.⁣

3️⃣ 𝗛𝗣𝗔 𝗔𝘅𝗶𝘀: Bacterial products can affect the release of hormones. This is particularly true for the hypothalamus and pituitary gland and how it affects cortisol from the adrenal glands.