Bacteria in the Gut Can Be a Pain in the Brain

Bacteria on slide

By Dr. Peter Abaci

Trillions of microbes live in your gastrointestinal tract, including up to a thousand different species of bacteria. This mass, called the microbiome, contains more cells than the total number of cells in your entire body! Many of these microbes have a major effect on your immunity and overall well-being, with some protecting against illness (eating up carcinogenic substances and other invaders) and producing certain vitamins, and others triggering chronic diseases like rheumatoid arthritis or asthma. When there is a proper balance between the helpful and unhelpful microbes in the gut, good health should reign. But when the unhelpful become dominant, disease can set in.

The composition of your microbiome is completely unique, the result of what you ingest, your environment, genetics, stress levels and a host of other factors. Generally, the microbiome is a fairly stable community, but it can be changed for the worse by antibiotics and other medications, poor nutrition, bacterial infections, stress and other factors. Two-thirds of the body’s immune cells are housed in the gut, and they communicate with the rest of the immune system, so when the microbiome becomes unbalanced, inflammatory cells throughout the body can be activated. In fact, an upset microbiome is thought to be linked to inflammatory conditions that range from obesity and autoimmune conditions to chronic pain. An upset microbiome can also negatively affect your brain, and ratchet up its perception of pain.

The Gut and the Brain Like to Chat

Data collected over the past several years confirms that gut microbes communicate with the central nervous system (CNS); and this communication appears to be a two-way street. This means that the microbes affect CNS function (including brain function), and the CNS, in turn, affects the microbial composition of the gut through its actions on the gastrointestinal (GI) tract. The gut and brain communicate with each other in a variety of ways, including through immune cell messengers, hormones, and nerve impulses that travel back and forth. And emerging research suggests that this gut-brain interaction has a big impact on overall health and well-being. Changes in the gut microflora directly affect brain activity, while at the same time, alterations in the messages flowing from the brain can disrupt the microflora.

Chronic pain conditions that are known to have a strong link to the microflora composition in the gut include autoimmune disorders like rheumatoid arthritis (RA) and psoriatic arthritis. Those with RA, for example, are more likely to have the bacteria Prevotella copri in their intestines, perhaps due to a genetic disposition. Studies indicate that Prevotella copri inhibit the action of some of the more protective strains of gut bacteria, perhaps contributing to the onset or continuance of rheumatoid arthritis.

Conversely, activity in the brain can directly alter the microflora in the gut. For example, studies show that when animals are put into a stressful social situation, significant changes take place in the composition of their gut microflora. The stress response activated by the brain leads to a chain of events, including the release of inflammatory mediators that directly alter what is happening in the gut lining and disruptions to the balance of the gut flora. These disruptions, in turn, lead to the production of even more inflammatory mediators, creating a vicious cycle between the brain and gut.

Studies have found links between changes in certain gut bacteria concentrations and levels of depression, fatigue, anxiety, and perceived abdominal pain. A whole host of other diseases are also being looked at for links to the gut microbiota, including autism, multiple sclerosis, and obesity.

When you make decisions about what to put into your body, opt for choices that will help create the optimum gut microbiota to provide the best feedback possible to your ever-changing neuroplastic brains.


Image courtesy of NIAID at

Contest will run September 23-30





“This book is a powerful tool for patients who don’t understand why the pain management system needs changes....Dr. Abaci lays out the compelling reasons for this and backs [them] up with [his] personal experiences as a pain-management provider and as someone who has faced living with chronic pain himself.”

— Barby Ingle, president, Power of Pain Foundation

"Conquer Your Chronic Pain is a must-read for anyone living with pain. Following Dr. Abaci’s simple steps, you will learn important tools to not only manage (and heal) pain, but also reclaim happiness, purpose and overall wellness in life.”

— Paul Gileno, founder & president, U.S. Pain Foundation


Q&A session 

Wednesday, 9/21 - 5 p.m.

Join the author, Dr. Peter Abaci in Los Gatos, CA for a Q&A session. We will be discussing this book as well as pain-awareness month. 

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