What Is Intestinal Dysbiosis?

Microbiota plays an important role in our health because it interacts with gastrointestinal functions. So, what is intestinal dysbiosis?
What Is Intestinal Dysbiosis?

Last update: 13 May, 2021

Intestinal dysbiosis refers to the loss of beneficial bacterial mass or intestinal microbiota. It’s a very common problem that’s related to autoimmune diseases, inflammation, allergies, and obesity, among other chronic diseases. So, what is intestinal dysbiosis?

First, it’s necessary to remember that intestinal flora has recently been labeled as an organ. This is because it has diverse functions that influence nutrient metabolism and overall health.

What is microbiota?

To begin with, we have to talk about what it actually is. Microbiota is a community of different microorganisms distributed throughout the human body (skin, mouth, eyes, genital areas and, abundantly, in the intestine).

These populations form a mutually beneficial relationship with the host, which is known as symbiosis. This study published in the World Journal of Gastroenterology shows this. When there’s an imbalance and the relationship is detrimental, it’s called intestinal dysbiosis. Many people refer to gut microbiota as a “metabolic organ” as it:

  • Preserves the integrity of the mucosa
  • Is the first barrier to pathogens such as E. Coli
  • Regulates the immune system cell’s functions
  • Helps with the synthesis of vitamins such as K, D and complex B
Woman's intestines.

Gut microbiota characteristics

The microbiota’s composition is quite complex and can undergo changes (acute or chronic) due to exogenous factors (such as lifestyle, habits, interaction with pathogens and/ or chemicals, environmental agents) and endogenous factors (genetics).

Interestingly, there are more microorganisms in the human body than there are cells. Specifically, more than 1000 bacterial species live in the body (100 billion bacteria). The most common are Firmicutes and Bacteroidetes.

Human microbiota

The microbial population that colonizes in the intestine is there from birth. It’s then strengthened with vaginal delivery and exclusive breastfeeding until 6 months old. With food and environmental interactions, changes in the microbiota’s composition will occur. This will define the person’s health.

According to a study published in the Spanish Journal of Pediatric Endocrinology by Tinahones F et al, the predominant microorganisms in the human gastrointestinal tract are:

  • Stomach: Helicobacter pylori (Proteobacteria), Lactobacillus (Firmicutes), Streptococcus (Firmicutes)
  • Duodenum: Bacteroides (bacteriodetes), Lactobacillus (Firmicutes), Streptococcus (Firmicutes), Staphylococcus (Firmicutes)
  • Jejunum: Bacteroides (Bacteriodetes), Lactobacillus (Firmicutes), Streptococcus (Firmicutes), Bacillus (Firmicutes)
  • Ileum: Bacteroides (Bacteriodetes), Clostridium (Firmicutes), Enterobacteriaceae (Proteobacteria), Enterococcus (Firmicutes), Lactobacillus (Firmicutes), Veillonella (Firmicutes)
  • And, lastly, the colon: Bacteroides (Bacteriodetes), Bacillus (Firmicutes), Bifidobacterium (Actinobacteria), Clostridium (Firmicutes), Enterococcus (Firmicutes), Eubacterium (Firmicutes), Fusobacterium (Fusobacteria), Peptostrepsococus (Firmicutesum Firmicutes), Streptococcus (Firmicutes)

What is intestinal dysbiosis?

Thanks to numerous studies, we know that microbiota (specifically the intestinal microbiota) plays an important role in the body’s functions. When those populations change, it can lead to the development of diseases.

Intestinal dysbiosis is when there’s an imbalance between the structure and composition of the microbial populations in the intestine. When the microbiota changes, it can directly or indirectly result in the development of numerous pathologies.

Intestinal microbial

Gut-brain axis and gut microbiota

The gastrointestinal tract and the nervous system are intimately connected through the axis known as the “gut-brain.” This is a complex bidirectional system where the enteric and central nervous systems interact with each other, developing through endocrine, immune and neurological circuits.

This has led to multiple theories about the multifactorial origin of neuropsychiatric diseases (such as autism spectrum disorders and depression), metabolic (such as diabetes and obesity) and tumors (such as colorectal cancer).

Gut-brain axis characteristics

Recent studies show a strong relationship between the gut-brain axis and the composition of the gut microbiota, with multiple diseases. Specifically:

  • There are neuronal signals that influence motor, sensory and secretory functions within the gastrointestinal tract that, in turn, regulate inflammatory processes and the microbiota structure.
  • Also, intestinal signals can regulate functions within the nervous system.

Relationship between intestinal dysbiosis and obesity

According to a study published in Nutrients by Niccolai E et al, when our bodies are subjected to chronic stress, cortisol is released, and this alters the permeability of the intestine and its protective barrier. In addition, this affects the microbiota’s composition, causing intestinal dysbiosis. As a result, the intestinal microbiota causes these changes:

  • Activating neurotransmitters that regulate appetite and satiety signals (such as serotonin)
  • Increasing the production of inflammatory cytosines
  • Producing changes in the fat reserve.

These changes trigger a favorable environment for the development of important metabolic alterations and cause unbalanced eating behavior. 

Measuring obesity

Importance of keeping the microbiota in balance

Finally, it’s essential to emphasize the importance of maintaining the correct composition of microbial population in the intestine. We know that our diet and genetic factors heavily influence its structure. 

So, we should eat a varied diet full of vegetables, fruits, grains and whole seeds. These are full of fiber, which is the intestinal bacteria’s main food.

Also, be sure to limit your consumption of processed foods, high in sugars or sweeteners. Also, try managing your stress through meditation and exercise. These are all important measures for avoiding intestinal dysbiosis. 

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  • Boem F, Amedei A .Healthy axis: Towards an integrated view of the gut-brain health. World J Gastroenterol. 2019;25(29):3838-3841.
  • Tinahones F. La importancia de la microbiota en la obesidad. Rev Esp Endocrinol Pediatr 2017; 8:15-20
  • Niccolai E, Boem F, Russo E, Amedei A. The GutBrain Axis in the Neuropsychological Disease Model of Obesity: A Classical Movie Revised by the Emerging Director “Microbiome”. Nutrients.2019; 11 (1):  1-25.