Did you know?
Experimental models have shown that altering the gut microbiome in animals can lead to changes in fat storage, insulin resistance, and even behavior changes, suggesting a direct role of the microbiome in these processes.
Microbiome Theory of Health and Disease
Researched by:
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Karen Pendergrass
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Karen Pendergrass
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease—four years before the first published case study.
Fact-checked by:
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Kimberly Eyer
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Kimberly Eyer
Kimberly Eyer, a Registered Nurse with 30 years of nursing experience across diverse settings, including Home Health, ICU, Operating Room Nursing, and Research. Her roles have encompassed Operating Room Nurse, RN First Assistant, and Acting Director of a Same Day Surgery Center. Her specialty areas include Adult Cardiac Surgery, Congenital Cardiac Surgery, Vascular Surgery, and Neurosurgery.
The Microbiome Theory posits that gut balance promotes health, while imbalances (dysbiosis) cause disease, suggesting restoration as treatment.
Research feed -
Karen Pendergrass
Researched by:
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Karen Pendergrass
ID
Karen Pendergrass
Fact-checked by:
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Kimberly Eyer
ID
Kimberly Eyer
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Karen Pendergrass
Overview 
Research 
Research Feed Overview
The Microbiome Theory of Health and Disease posits that microbiomes—complex communities of microorganisms residing in and on the human body—play a crucial role in maintaining health and contributing to the development of diseases. This theory has evolved from recognizing the microbiome’s influence on localized disease states to understanding its broader impact on systemic health and chronic conditions over the past few decades.
Function of the Human Microbiome
The human microbiome consists of bacteria, archaea, viruses, fungi, and protozoa that inhabit various body sites, including the gut, skin, mouth, and respiratory and urogenital tracts. The gut microbiome, in particular, is the most studied and is known for its role in digesting food, synthesizing vitamins, and serving as a barrier against pathogens.
Microbiome Development and Influences
The composition of an individual’s microbiome begins to develop at birth. It is influenced by the mode of delivery (vaginal vs. cesarean), diet, environment, medication use (especially antibiotics), and host genetics. This microbiome undergoes changes throughout life, reflecting lifestyle, diet, and health alterations.
Dysbiosis and Disease
Dysbiosis refers to the imbalance in the microbial communities that can lead to disease. This can be a decrease in microbial diversity, an overgrowth of harmful microbes, or a loss of beneficial microbes. Diseases associated with dysbiosis include inflammatory bowel disease (IBD), obesity, type 2 diabetes, cardiovascular diseases, and even mental health disorders such as depression and anxiety.
Key Mechanisms of Microbial Influence on Health
The human microbiome plays a crucial role in various bodily functions, impacting immune system modulation, metabolic processes, barrier functions, and neurological influences. It educates the immune system to distinguish between harmful and benign antigens, fostering immune tolerance and preventing inappropriate responses. Disruptions in this balance can lead to autoimmune diseases, allergies, and increased infection risks. Microbiologically, microbes are integral to metabolism by assisting in nutrient breakdown and synthesizing short-chain fatty acids, which are vital for colon health and influence the development of metabolic disorders like obesity and diabetes. They also maintain the integrity of mucosal barriers, protecting against pathogen translocation and systemic infections. Moreover, the microbiome affects neurological functions through the gut-brain axis, producing neurotransmitters that influence mood and behavior, linking it to various neuropsychiatric disorders. This comprehensive influence underscores the microbiome’s critical role in health and disease, offering promising avenues for therapeutic interventions.
| Function | Description |
|---|---|
| Immune System Modulation | The microbiome is instrumental in educating the immune system, helping it to distinguish between harmful and benign antigens. This interaction is critical for immune tolerance and preventing inappropriate immune responses. Disruptions in this balance (dysbiosis) can lead to autoimmune diseases such as rheumatoid arthritis and multiple sclerosis, exacerbate allergic reactions, and increase susceptibility to infectious diseases. For instance, reduced diversity in gut microbiota has been associated with an increased risk of conditions like asthma and eczema. |
| Metabolic Functions | Microbes play a crucial role in the host’s metabolism by influencing energy balance and the extraction and synthesis of nutrients. They assist in the breakdown of complex carbohydrates and produce short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate, which are essential for colonic health. These SCFAs also serve as energy sources for the host and regulate lipid and glucose metabolism, influencing the development of metabolic disorders such as obesity, diabetes, and even cardiovascular diseases. Research has shown that specific microbial profiles can predispose to greater energy harvest from the diet, contributing to obesity. |
| Barrier Function | The microbiome supports the integrity of the mucosal barriers (intestinal, respiratory, and urogenital tracts) by outcompeting pathogenic microbes and producing substances that strengthen the mucosal integrity. A robust barrier prevents the translocation of pathogens and toxins into the host’s systemic circulation, thereby reducing the risk of systemic infections and chronic inflammatory states like sepsis. Alterations in this microbial barrier can lead to increased intestinal permeability, often called “leaky gut,” which has been linked to various inflammatory and autoimmune conditions. |
| Neurological Influence | The microbiome supports the integrity of the mucosal barriers (intestinal, respiratory, and urogenital tracts) by outcompeting pathogenic microbes and producing substances that strengthen the mucosal integrity. A robust barrier prevents the translocation of pathogens and toxins into the host’s systemic circulation, reducing the risk of systemic infections and chronic inflammatory states like sepsis. Alterations in this microbial barrier can lead to increased intestinal permeability, often called “leaky gut,” which has been linked to various inflammatory and autoimmune conditions. |
Implications for Clinical Practice and Public Health
| Category | Description |
|---|---|
| Diagnostic Tools | Advances in sequencing technologies allow for detailed analyses of microbiome compositions at various body sites. This enables the development of biomarkers for early disease detection and personalized treatment strategies. |
| Therapeutic Approaches | Probiotics and prebiotics enhance the microbiome with beneficial microbes, while dietary modifications help manage and prevent diseases by altering microbiome composition. Additionally, phage therapy targets specific bacterial populations, showcasing its potential as a promising research area in microbiome health management. |
| Preventive Medicine | Understanding the role of the microbiome in disease enables preventive health measures, such as early-life interventions to establish a healthy microbiome. These strategies could have long-term health benefits. |
Conclusion
The Microbiome Theory of Health and Disease provides a comprehensive framework for understanding the integral role of microbial communities in human health. As research continues to unfold, the potential for microbiome-targeted interventions in clinical practice grows, promising to revolutionize preventive and therapeutic health strategies across a wide spectrum of diseases.
Research
Studies have demonstrated that fecal microbiota transplantation (FMT) can restore healthy microbial balance in conditions like recurrent Clostridioides difficile infection, suggesting the potential for microbiome-based therapies.
Research Feed
Meta-analysis of gut microbiome studies identifies disease-specific and shared responses
December 5, 2017
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Microbes
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Autoimmune Diseases
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Autoimmune Diseases
Did you know?
Americans are over three times more likely to suffer from autoimmune diseases compared to the global average, with approximately 16.67% of the U.S. population affected versus 5% worldwide.
This meta-analysis standardized and re-analyzed data from 28 gut microbiome studies across ten diseases, identifying consistent microbiome signatures associated with specific diseases and a non-specific response common to multiple conditions. Key findings suggest both potential microbial diagnostics and treatments, emphasizing the importance of understanding shared versus disease-specific microbial responses in future research and clinical applications.
Autoimmune Diseases
Autoimmune disease is when the immune system mistakenly attacks the body's tissues, often linked to imbalances in the microbiome, which can disrupt immune regulation and contribute to disease development.