What is Dysbiosis?

bacteria2The human body hosts trillions of germs, and these microorganisms and their DNA is collectively called the human microbiome. While most of these microbes are considered beneficial to the human host, others are potentially pathogenic under the right circumstances. The human microbiome consists of microorganisms that live in the mouth, lungs, sinuses, gastrointestinal tract, and several other places in and on the body. We provide these microbes with food and shelter, and they provide us with functions that stretch far beoynd the scope of our own physiological capabilities. However, if we perturb these microbial ecosystems, the relationship between the microbiome and the human host can change from symbiosis to dysbiosis.

Dysbiosis can happen on any exposed surface or mucous membrane

Dysbiosis (also called dysbacteriosis) refers to a condition with microbial imbalances on or inside the body. Dysbiosis is most prominent in the digestive tract or on the skin, but can also occur on any exposed surface or mucous membrane such as the vagina, lungs, mouth, nose, sinuses, ears, nails, or eyes” (1).

Perhaps the most well-known type of dysbiosis among the general public, is vaginal dysbiosis. Imbalances in the microbial communities in the vagina set the stage for vaginal thrush and other microbial disturbances (2,3).

Dysbiosis in the mouth is also very common and results in tooth decay and poor periodontal health (4).

The majority of microbes live in the gastrointestinal tract, and more specifically in the large intestine where they digest some of the food we eat and regulate our immune system and intestinal barrier function. Gut bacteria are essential to our health and provide several important functions we can’t do without:

  • Essential metabolic functions (5,6)
    Production of vitamins, amino acid synthesis, digestion of fermentable substrates, production of short-chain fatty acids, and bile acid biotransformation.
  • Ensures protection (5,6)
    Commensal bacteria prevent pathogenic colonization and regulate the immune system
  • Structural and histological functions (5,6)
    Bacteria in the gut ensure intestinal structure and function

While the largest colonies of bacteria live in the colon, gut dysbiosis can also affect the upper parts of the gastrointestinal tract.

Hundreds of different types of microorganisms make up the gut microbiota, and various species of bacteria have different functions in the body. Even in a balanced state, a lack of microbial diversity leads to poor digestion and low-level inflammation, since microbes produce enzymes that are needed to digest otherwise undigestible food components.

Since bacteria in the gut have so many important functions in the body, disruptions in this microbial ecosystem are also linked to the most serious health problems. Altered composition of the gut microbiota can lead to serious immune deregulation, increased intestinal permeability, endotoxemia, bacterial infection, abnormal bacterial metabolite levels, altered energy and lipid metabolism, and chronic low-level inflammation (7,8,9). When considering the vital importance of a healthy and balanced microbial ecosystem in the gut, it’s no surprise that gut dysbiosis is linked to a plethora of human disorders such as autoimmune disease, allergic disease, irritable bowel syndrome, metabolic disease, alcoholic liver disease, bacterial infection, and colorectal cancer (7,8,9).

Dysbiosis is extremely common

The obvious disconnect between our evolutionary past and the modern envoronment has led to dramatic changes in the human microbiome. Since the majority of people in the industrialized world use antibiotics some time during their life, eat a typical western diet high in processed and refined food, spend little time outdoors compared to our ancestors, and have limited exposure to soil microbes and other types of bacteria, I believe dysbiosis is now quickly becoming the leading cause of disease in the modern world.

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  1. […] current belief is that gut dysbiosis changes the communication between gut and brain through several different mechanisms, and that […]

  2. […] and prebiotics soon could be on the market. A lot of health disorders are characterized by gut dysbiosis, and one company has now begun financing the testing and production of a Microbiome Modulator that […]

  3. […] previously written about how dysbiosis can lead to insulin resistance, weight gain, and obesity. While I’ve focused on the […]

  4. […] is strongly associated with the components of the metabolic syndrome suggests that poor diets, dysbiosis and increased intestinal permeability are major causes of inflammation in obese and overweight […]

  5. […] non-communicable, could be contagious in the sense that we share bacteria with other humans. dysbiosis is a key driver of chronic disease, and it can be hypothesized that close contact (e.g., kissing, […]

  6. […] research has implicated dysbiosis and increased intestinal permeability in most of the chronic diseases we see in todays society. […]

  7. […] Gut dysbiosis: “Dysbiosis is a state in which the microbiota becomes altered as a consequence of an alteration in the composition of the microbiota, a change in bacterial metabolic activity, and/or a shift in local distribution of communities” Gut dysbiosis is primarily used to describe changes in the balance between “good” and “bad” microorganisms in the gut (2). […]

  8. […] immune cells (6). When we consider the gut as the primary immune organ, it’s no surprise that gut dysbiosis and leaky gut have been linked to inflammation and disease. Alterations in the gut microbiota […]

  9. Gut bacteria control our digestive health says:

    […] Since gut bacteria play an essential role in the digestion of nutrients and in the development and control of the immune system, there’s no surprise that celiac disease, clostridium difficile infection, food intolerance, gallstones, irritable bowel syndrome, inflammatory bowel disease and most other types of digestive diseases are characterized by gut dysbiosis. […]

  10. Gut dysbiosis associated with gallstones, study finds says:

    […] The pathogenesis of Cholelithiasis isn’t fully established, but new research suggests that gut dysbiosis could be an important underlying cause. Cholelithiasis can then be added to the growing list of […]

  11. […] Gut dysbiosis is often accompanied by abnormal host appetite. A typical western diet could perturb the gut microbiome, and building on the information in the previous paragraph, it seems possible that the subsequent growth of certain microbial species following antibiotics, poor diet etc. results in an increased desire for food that contains substances that feed these microbes. […]

  12. […] increased intestinal permeability. Moderate-severe cases are characterized by more severe cases of gut dysbiosis and/or leaky […]

  13. […] gut, and since gut microbiota can impact our appetite and food preferences, it seems likely that dysbiosis also contributes to “food […]

  14. […] the skin (7). The problem at the moment is that although there are thousands of articles discussing dysbiosis in the gut, mouth, lungs and vagina, few studies have looked at the relationship between body care […]

  15. […] previously highlighted the fact that gut dysbiosis sets the stage for grain-related disorders, and as the evidence is now piling up, I’m more […]

  16. […] Candida albicans is a normal part of a healthy individuals gut flora, and it’s presence is kept under control by normal bacterial populations (1,9). However, antibiotics, increased carbohydrate consumption and several other factors  have made us prone to candida overgrowth. Decreased numbers of “friendly” flora and compromised host resistance make it possible for the yeast to thrive. Candida rarely works alone, and several other opportunistic microorganisms might be involved (14). For that reason it’s more accurate to talk about dysbiosis. […]

  17. […] increased intestinal permeability. Moderate-severe cases are characterized by more severe cases of gut dysbiosis and leaky […]

  18. […] Gut dysbiosis is often accompanied by abnormal host appetite. A typical western diet perturbs the gut microbiome, and building on the information in the previous paragraph, it seems possible that the subsequent growth of certain microbial species following antibiotics, poor diet etc. results in an increased desire for food that contains substances that feed these microbes. […]

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