The intestinal flora refers to the totality of microorganisms that colonise the human intestine. These include many different bacteria, as well as eukaryotes and archaeae, which make up the other two large groups. The intestinal flora only develops from the time of birth.
Until then the gastrointestinal tract is sterile. The intestinal flora is very important for digestion and human health and can contribute to the development of diseases in case of imbalance. In total, the human digestive tract contains about 10 times as many microorganisms as the human body contains cells.
Development of the intestinal flora
In the womb, the gastrointestinal tract of the unborn child is not yet colonized with microorganisms. The first bacteria only get there during birth. Initially, these mainly originate from the mother’s genital area, as the child comes into contact with this area during birth.
The first settling bacteria are therefore mainly streptococci, enterobacteria and Escherichia coli (E. coli). Children born by Caesarean section do not come into contact with these germs. Their digestive tract is initially colonised mainly by germs of the maternal skin flora.
With the first food, a large number of other bacteria enter the child’s gastrointestinal tract. These are mainly lactic acid bacteria. These acidify the environment in the digestive tract, which limits the reproduction of harmful pathogens.
In the course of life, the intestinal flora builds up more and more and the colonisation by micro-organisms becomes more and more dense. A healthy adult human being is home to at least 500 to 1000 different species of bacteria in his or her digestive tract. The various species of bacteria prefer to settle in specific sections of the digestive tract. The small intestine, for example, is home to an increased number of Lactobacillus and Enterococcus species, while the much more densely populated large intestine is home to Bacteroides, Bifidobacterium, Clostridium and many other species of bacteria.
Function of the intestinal flora
The intestinal flora plays a very important role in maintaining health. Thus, the “good” microorganisms are essential for the defence against pathogenic germs and contribute to the fact that these cannot multiply and settle unchecked in the digestive tract. At the same time, through their metabolism the microorganisms supply the human body with various important food components, such as many vitamins, which the human body could not isolate from food on its own.
In addition, the intestinal flora plays a major role in the digestive processes. The bacteria split sugar and fatty acids and stimulate the intestinal motor function. Depending on the composition of the intestinal flora, conclusions can be drawn about the metabolic situation of the person concerned.
For example, the intestinal flora of overweight persons is said to be mainly home to Firmicutes and less to Bacteroides bacteria, whereas this balance is shifted in favour of the Bacteroides genus in slim persons. The intestinal flora is therefore in a reciprocal relationship with body weight. The extent to which it influences a person’s stress management and emotional state is also being discussed.
Last but not least, the intestinal flora has an influence on the immune modulation in the human body and houses an important part of the immune system. The exact processes that contribute to this are not yet fully understood. Malcolonisation of the digestive tract Various disruptive factors can throw the sensitive ecosystem of the intestine out of balance, which can result in malcolonisation of the digestive tract.
It is characterized by the predominance of one or more pathogenic germs, or the reduction or absence of useful microorganisms. Such an incorrect colonisation can be noticed by various symptoms, such as frequent abdominal pain, flatulence or a feeling of bloatedness, susceptibility to infections or food intolerances. By means of various tests at the doctor’s, such a false colonisation can be detected and, if necessary, treated.
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