Doctors call the intestinal flora the totality of the microorganisms present in the human and animal intestines. These influence digestion as well as the immune system and supply the body with vitamins. An imbalance in this bacterial ecosystem can lead to complaints and diseases in the intestinal tract.
What is intestinal flora?
The term intestinal flora is a collective term for all bacteria and microorganisms found in the human as well as animal intestines. In this context, the large intestine naturally contains a higher density of bacteria than the small intestine. The term “flora” originates from a time when bacteria were considered to be of plant origin. Even though this view is outdated, the term has persisted. The complete intestinal flora develops in humans during the first years of life. There is an interaction between the organism and the microorganisms settled in it, which is vital for both. The presence of a functioning intestinal flora is thus of immense importance for the host. Disturbances in this sensitive ecosystem can result from diseases or even permanent malnutrition. Such an imbalance can lead to pain and digestive discomfort that significantly affects the well-being of the individual. In most cases, however, intestinal health can be restored through medical means.
Anatomy and structure
The basic human intestinal flora is formed before birth. However, the intestine is initially only sparsely populated. The bacteria that reside there are primarily from the four well-known groups Enterobacteriaceae (esp. Escherichia coli), Bacillus, Bacteroides, and Enterococcus. An important influence on the formation of the ecosystem is the food, which contributes significantly to the composition of the intestinal flora, especially in children. In adults, between 10 and 100 trillion bacteria are found in the intestinal tract, depending on the state of health, diet and culture. This involves at least 500 different species. In individual cases, even up to 36000 different bacterial species have been detected. Especially the surface of the colon, but also other parts of the intestinal tract are colonized by these versatile microorganisms. Healthy adults have a total microflora mass of 1 – 2 kg.
Function and tasks
The totality of bacteria contained in the intestinal flora performs several functions that are of great importance to the host organism. In particular, the microorganisms located in the colon reliably help protect the organ from pathogens. In this context, physicians speak of colonization resistance. At the same time, the bacteria also influence the body’s entire immune system and contribute to a more effective defense. While the food ingested by humans feeds the microorganisms, these in turn are helpful for numerous digestive processes. They support the natural breakdown of food components, stimulate intestinal activity and provide the intestines with additional energy. Particularly during the digestion of dietary fiber, fatty acids are formed in the intestinal tract. These are formed with the help of the bacteria found there. The hard-to-digest food components are then metabolized and the remains excreted. This produces gases such as methane and hydrogen, which lead to foul-smelling flatulence – a process that may be unpleasant for the person concerned, but is essential for digestion. So-called xenobiotics (toxins foreign to the body that are absorbed through food and the environment) are broken down by the numerous bacterial strains, which is an enormous relief for the organism. The fat-soluble vitamin K, which the body needs, among other things, for the bones and for blood clotting, cannot be produced by humans themselves without the cooperation of the intestinal flora. Last but not least, the intestinal flora also influences the body weight of the individual. Whether a person develops (severe) obesity is at least partly also due to the ratio of certain intestinal bacteria to each other.
Diseases and ailments
If the intestinal flora gets out of balance and the ratio of the different bacteria to each other changes significantly, this can lead to clearly noticeable complaints. Primarily, these affect the digestive tract and are manifested by unpleasant flatulence, abdominal pain and a feeling of tension or a clearly bloated abdomen.It is often possible to determine which part of the intestine is affected. A disturbance of the flora of the small intestine leads to a bloated belly without bloating. If the flora of the large intestine is affected, strong intestinal gas occurs in addition to a bloated belly. Furthermore, the immune system of the entire body is also affected by the imbalance. This can lead to more frequent infections, not only in the gastrointestinal tract. Difficulties in digestion and sudden food intolerances can indicate a disturbance of the intestinal flora. The bacterial ratio gets out of balance especially if the affected person eats a particularly one-sided or unhealthy diet. Medications taken can also cause a temporary imbalance in the intestine due to their active ingredients. The latter include, for example, antibiotics, which are prescribed for many bacterial diseases. However, these fight not only the bacteria responsible for the disease, but also the beneficial bacteria, and can thus upset the ratio of microorganisms in the intestinal tract. In order to rebuild the intestinal flora, it is helpful to eat a balanced diet, especially one rich in fiber, over a period of several months. Foods with a high sugar and fat content should be largely avoided during this period. The intake of probiotics has a supporting effect. Usually the intestinal flora regenerates itself; if this is not the case, a so-called stool transplantation can be performed by the doctor to restore the balance of bacteria.
Typical and common intestinal diseases
- Crohn’s disease (chronic inflammatory bowel disease)
- Inflammation of the intestine (enteritis)
- Intestinal polyps
- Intestinal colic
- Diverticula in the intestine (diverticulosis)
