How do we benefit from the microorganisms that live within us?


This article explores the significant impact that microorganisms have within our body and the numerous roles they play, such as regulating vitamin and nutrient production to fight infections. Using the example of microbes acting within the intestine, in particular, this article will demonstrate how microbes have the ability to affect our health in a positive way. In this way, the author aims to challenge the widespread but false belief that all microorganisms are harmful, exemplifying instead that there are just as many positives as there are negatives.


Our skin forms a barrier to microorganisms in order to protect our organs and muscles from pathogenic infections. However, contrary to popular belief, microorganisms within our body are also highly important in terms of our digestive system and immune system development. Different microbes are responsible for maintaining internal conditions such as pH and information control. This article will examine the various benefits of microorganisms as they play a pivotal role in strengthening our defense system to prevent the spread of disease and enable us to build a strong immune system.[1]
Our microbial symbionts make up a large percentage of our bodies ranging up to 20 million microbial genes. When we eat, living in our digestive system help us to obtain our nutrients by breaking down some of our food into essential vitamins such as biotin and Vitamin K. These vitamins are significant as they regulate blood sugar levels, prevent osteoporosis, and reduce menstrual pain. Figure 1 displays Escherichia coli bacteria which helps our digestive system in many ways, such as by protecting the intestinal tract from other bacterial invaders. This, therefore, aids our digestion and enables us to remain healthy.
SEM image for Escherichia Coli  

Figure 1. A photo depicting the microscopic shape of E. coli bacterium.[2]

Results & Discussion

The gut accommodates billions of microbes that impact our health in a positive way by removing toxins. Microflora is a term used to describe a collection of bacteria which exists within human tissue and fluids. Our microflora consists of gastrointestinal microbiota that prevents the infiltration of pathogens into squamous epithelial cells. The microbiome interacts with cells in the lining of the intestines, helping them to absorb nutrients and energy, strengthening the immune system. A bacterium known as Escherichia coli produces vitamin K2 which is vital in enabling blood clotting and promoting food absorption.[3]
When there is an infection, B cells produce antibodies which are specific to an antigen. The antibodies detect antigens on the surface of pathogenic molecules and attack them using T cells. Bacteria can aid the immune response by reducing inflammation. They increase the number of T regulatory cells within the gut and signal to antigen-presenting cells to release an anti-inflammatory molecule named cytokine IL-10. This chemical lowers the response of inflammatory T cells preventing damage to tissue[4]. Therefore, the gut bacteria living within the human body promotes protection as opposed to causing the disease. Your gut microbiome diversifies the minute you are born and various types of bacteria grow such as bifidobacteria (grown in babies intestines that help to digest the sugars in breast milk) and fibre digesting bacteria that form short chain fatty acids to prevent humans from contracting heart disease or diabetes.

Figure 2. A diagram illustrating the organisation of the digestive system and the different microflora found in each organ. The number of microorganisms typically found in each location is seen on the right[5]

The composition of our intestinal microflora (see Figure 2) is an important field in scientific research, as it was discovered that obese people have less diverse gut bacteria, mainly consisting of firmicutes, as opposed to lean people who have a higher percentage of bacteroides. Our digestive system contains a range of bacteria which are significant for enzyme production such as ß-galactosidase and amylase. ß-galactosidase is significant as it is a glycoside hydrolase enzyme that catalyses the hydrolysis of b-galactosidase into monosaccharides.[6] Additionally, our bacteria aids in the regulation of the intestine’s acidity and food metabolism which is highly significant in terms of preventing the damage of body cavity linings and epithelial cells. By producing vitamins, our bacteria keeps us healthy as our bodies are not deficient. This therefore aids digestion.[7]
Our bodies all contain different hormones that can affect our hunger, some include ghrelin, leptin and peptide YY. These play a pivotal role in weight loss and obesity as a study has shown that 1 in 60 overweight adults discovered that taking propionate (a short chain fatty acid) SCFA led to increasing levels of peptide YY and henceforth influencing one’s hunger. In terms of obesity, a study showed that those who are obese had a less diverse range of bacteria within their gut as compared to non-obese individuals. There are two types of gut bacteria that promote prevention of weight gain known as Christensenella minuta and Akkermansia muciniphilia. The latter works by feeding on the gut lining mucus and strengthens the intestinal barrier, the microbes produce an SCFA that can aid in regulation of fat storage. Some foods that contain this gut bacteria include cranberries, black tea and flaxseeds. The other gut bacteria is associated with an individual’s genetic makeup hence is normally hereditary. Aerobic exercises, such as swimming, running or walking, help a considerable amount in increasing the healthy bacteria within our gut. These help support the barrier of the gut, providing stability for good gut bacteria and reducing the high risk of imbalances in the intestinal tract. This regulates your body fat, and hence, regular activity during the week helps us to lose weight and stay lean.
Furthermore, the exploration of microorganisms has led to the development of medical treatments such as insulin for diabetic patients. Microorganisms have also been proven to have many environmental benefits, including bacteria that aid nitrogen- fixation in plants for growth.


Therefore, it is important to understand that the majority of the microorganisms within our organs are not harmful but aid in digestion and nutrition. Although microorganisms do cause disease, there are a number of protective mechanisms in place to help prevent this. The bacteria that live in the body’s flora contain millions of different species of bacteria, and these are significant in terms of contributing to our specific immune response.

  1. Lumen Learning. “Bacterial Infections of the Gastrointestinal Tract”.
  2. “E coli 0157:H7 Infection Early Symptoms, Treatment, and Prevention”.
  3. Centers for Disease Control and Prevention. \”Helicobacter pylori: Fact Sheet for Health Care Providers.\” Updated July 1998.
  4. Ivan F. N. Hung and Benjamin C. Y. Wong. \”Assessing the Risks and Benefits of Treating Helicobacter pylori Infection.\” Therapeutic Advances in Gastroenterology 2 (2009)
  5. Can intestinal flora help cancer research” –
  6. Jaya Sureshbabu. \”Shigella Infection Workup.\” Medscape. Updated Jun 28, 2016.
  7. T. L. Cover. \”The Vacuolating Cytotoxin of Helicobacter pylori.\” Molecular Microbiology 20 (1996) 2: pp. 241–246.

About the Author

Kajol Jain loves reading scientific journals and the latest discoveries in science. She also enjoys visiting museums to see artefacts and evidence for evolution. In her spare time she is fond of playing netball and chess.

1 thought on “How do we benefit from the microorganisms that live within us?”

  1. Mauricio Alfredo Ondarza Beneitez

    May I take your image to be published on a seaweed chapter regarding their benefits on human microbiota health?
    Thanks for your kindly answer
    I remain Cordially yours, Dr. Mauricio Ondarza (Mexico)

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