Trust Your Gut: How the Microbiome Plays a Fundamental Role in Overall Health

Most of our healthcare discussions and innovations surround topics that impact the major organ systems in the human body, such as the cardiovascular, gastrointestinal, neurological, endocrinological, urological, immunological, hematological, reproductive, and musculoskeletal systems. However, most people, including healthcare professionals, have a lot to learn about the microbiome.

The microbiome, which is considered by some a distinct and essential organ system within the human body, plays a fundamental role in human health.

What is the Microbiome?

The microbiome is a diverse, complicated and until recently often overlooked ‘organ system’. It is comprised of 500-1000 species, which includes bacterial, viral, and fungal species. These species account for 100 trillion organisms encoding 100-fold more unique genes than our own genome. Bacteroides, known as gram negative bacteria, and Firmicutes, known as gram positive bacteria, are the most prevalent organisms in the microbiome, and they work symbiotically. A microbiome in healthy balance will have all existing microorganisms residing in a delicate, natural relationship with the cells lining the interior wall of the colon.

The microbiome plays a key role in metabolism, gut cell health, the immune system, and susceptibility to disease. A healthy, stable microbiome is one that balances the cooperative and competing network of microbes. In disease states, this balance is off, and the microbiota become compositionally unstable, and less diverse compared to normal. Dysbiosis is the disruption of the volume and diversity of the gut microbiome; this can be caused by stress, diet, hygienics, and the use of antibiotics. Dysbiosis can predispose to several disease processes.

The Role of the Microbiome in Gastrointestinal Infections

Clostridium Difficile infection (CDI) is a highly infectious bacterium that can colonize and severely infect the large intestine. CDI poses a significant public health issue in this country with an annual mortality of 30,000 in the US, with a 20% chance of recurrence after an initial infection, 40% after one recurrence, and 60% after a second recurrence. With each episode there is a progressive loss of fecal microbial diversity, which significantly decreases the health and resilience of the gut.

To restore this loss, a Fecal Microbiota Transplantation (FMT) stands as an effective treatment with a 90% success rate in severe CDI cases. FMT repairs the ecological balance and diversity of the gut microbiome, facilitating a balanced production of bile acids and short chain fatty acids which ultimately effects changes in the innate and adaptive immune system of the patient.

This model lends credence to the hypothesis that restoration of a healthy gut microbiota can reproducibly correct a severe and specific microbial dysbiosis, and effectively improve disease outcomes.

In November of 2022, The Food and Drug Administration approved the first fecal microbiota product. Reybota (Ferring Pharmaceuticals) was approved for the prevention of recurrent CDI in patients 18 years and older. It is indicated for use after a patient has completed antibiotic treatment for recurrent CDI. Reybota is derived from stool donated by qualified individuals and is administered per rectum in a single dose. This represents the first major application of a clinically proven microbiota manipulation that successfully impacts a major public health threat.

The Future of Microbiome Research

Given that the microbiome influences nutrition, immunity, behavior, and disease, it is no surprise that this area has generated significant interest in the past 5-10 years. Researchers seem ‘infatuated’ with the microbiome. Even venture capital firms are starting to take notice, with over 1.6 billion dollars of capital investment in microbiome biotech companies last year alone.

Microbiome research focuses on behavior, interactions, and function of microbial communities within a specific environment. This could help in the discovery of pathology and disease mechanisms while promoting the development of novel diagnostic and therapeutic interventions. Altering the microbiome to treat or decrease the risk of disease may be done more efficiently than finding therapeutics that rewrite the human genes linked to a certain disease. The microbiome is the only “organ” that can be replaced without surgery!

I would propose that the microbiome is a determinant of chronic disease, and a healthy microbiome is important in health maintenance. The concept of promoting ecological gut health balance, which is what many prebiotics, probiotics, and FMT claim to do, is not part of the traditional disease paradigm that has governed health related products in the United States for years.

Ongoing clinical research, with industry leaders like ObjectiveHealth, will get us closer to realizing the potential that the microbiome has in promoting and improving medicine.