There are several trillion bacteria in our intestines. While we live in helpful coexistence with most, some microorganisms can lead to various diseases. If these unhealthy bacteria predominate, this is referred to as dysbiosis. Research is currently being carried out into the influence of the intestinal flora on diseases such as diabetes, Crohn's disease, irritable bowel syndrome and food allergies. The text explains in more detail how dysbiosis occurs, what influence it could have and how it is treated.
What is dysbiosis?
Dysbiosis describes an imbalance of different bacteria in a certain body environment. Although the terms dysbiosis or dysbacteria can theoretically be used for all bacterial populated body milieus, for example for the mouth, the skin or the vagina, in most cases they refer to the intestine.
What does intestinal dysbiosis mean?
A large number of bacteria live in the intestine, in particular the colon is heavily populated. This bacteria do not cause diseases, but are for health-preserving for the body. They help with the digestion of long chain carbohydrates and produce fatty acids and vitamins. They also protect the intestines against infections by depriving pathogens of the necessary nutrients and maintaining an optimal pH value. At the same time, they are in a protected environment in the intestine and get enough nutrients themselves. This coexistence of humans and bacteria, from which both parties benefit, is called symbiosis. However, if the balance is disturbed and the intestinal flora changes in such a way that it harms humans, this is called dysbiosis.
How many bacteria are there in the intestine?
Everyone has an intestinal flora, also called their microbiome, that is put together a little differently and thus is as individual as a fingerprint. More than 1000 different bacterial species can be part of a microbiome, and a total of up to 100 trillion unicellular organisms are found in the intestine.
How does a healthy intestinal flora develop?
The intestine is sterile before birth, so there are no microorganisms in it. During childbirth, the child comes into contact for the first time with maternal vaginal and intestinal colonization. The intestine is initially populated with the bacteria located there. Children born by Caesarean section are more likely to be colonized with skin-resident bacteria.
Through nutrition and environment contacts, other bacteria are added until there is a balance between the second and fourth year of life. According to the current state of research, this is also partially genetically predetermined - The genetic makeup seems to have an influence on which bacteria survive and which cannot colonize. Even after the fourth year of life, the intestinal flora is subject to fluctuations. This depends on age, the nutrition, stress, the hygiene status and the use of antibiotics.
What are the most common causes of dysbiosis?
Antibiotics as a cause of dysbiosis
Different environmental influences can lead to a major change in the microbiome. A classic example is the use of antibiotics: It can change the composition of up to 90 percent of the intestinal bacteria. If health-promoting bacteria are killed as "collateral damage" by the antibiotic, this gives pathological germs the opportunity to multiply. Thus, especially in the case of elderly sick people, antibiotic therapy occasionally causes pseudomembranous colitis. This inflammation of the colon is caused by an intestinal overgrowth of the bacterium Clostridium difficile and leads to severe diarrhea.
Improper diet as a cause of dysbiosis
But it does not always have to be caused by antibiotics: Everyday nutrition also syms to result in dysbiosis at times. In this way it was found that in particular the “Western” diet with its high fat and sugar content leads to an increased growth of unfavorable bacteria in food. These bacteria are commonly referred to as putrefactive bacteria because they tend to produce foul-smelling hydrogen sulfide gases.
What are the effects of dysbiosis?
In some cases, such as pseudomembranous colitis, dysbiosis leads directly to a clinical issue. However, the impact of dysbiosis is often more subtle. The intestinal flora plays an important role in the regulation of the immune system and is affected by inflammatory processes. Bacteria influence which organisms and food components are regarded as harmless and which are to be attacked by the immune system.
If a mistake is made, the immune system can either recognize too few, which leads to infections, or too many, which can result in food allergies and autoimmune diseases. In addition, it is assumed that a natural “bacterial turf” in the intestine protects the mucous membrane and limits its permeability. If there is an imbalance, the gut wall becomes more permeable and more toxins from food get into the bloodstream.
What is the relationship between dysbiosis and obesity?
Although it is known that, for example, nutrition can change the microbiome, it is ultimately not possible to determine exactly whether dysbiosis is the cause or consequence with may diseases. However, researchers derive the influence of the intestinal flora on various diseases from the previously described mechanisms of action. The dependency of body weight on the microbiome, for example, has long been known. High-fat food seems to change the bacterial composition, which in turn can use fats more extensively, and so leads to an increase in weight. Mice that received a stool transplant from obese mice also increased their weight as a result. However, it has not yet been clarified exactly which bacteria bring about this effect.
How are dysbiosis and diabetes related?
If the intestinal barrier is weakened by dysbiosis (leaky gut), more surface molecules of bacteria can enter the bloodstream. This activates the immune system and puts the body in a kind of "permanent inflammatory state". Increased level of inflammation is known as a risk factor for the metabolic syndrome, which can be associated with obesity, increased blood lipid levels and impaired glucose tolerance. The consequences of metabolic syndrome include arteriosclerosis, the danger of a heart attack and diabetes mellitus type 2, Through this mechanism, an unbalanced intestinal flora appears to contribute to the development of these diseases. The development of the autoimmune disease diabetes mellitus type 1, which often occurs in childhood, seems also to be related to nutrition and the microbiome. Here too, no clear link has been established between certain bacteria and the course of the disease.
Is there a link between dysbiosis and inflammatory bowel disease?
In other cases, a broken intestinal barrier can cause inflammatory cells not only in the blood, but in the intestinal wall to be activated. Researchers see the resulting inflammation as an explanation for the development of inflammatory bowel diseases like Crohn's disease, microscopic colitis or ulcerative colitis. The influence of different fat and oil combinations in the treatment of these diseases is already being investigated in order to be able to offer specific nutritional advice soon.
Can dysbiosis lead to food intolerance?
It has long been known that breastfeeding infants has a protective effect for the child in the first four months of life. This relates, for example, to the risk of food allergies and celiac disease (an intolerance reaction to the cereal protein gluten). Breast-fed children have a different bacterial composition in the intestine than children who received formula food from the bottle. It is being investigated whether certain bacteria in the intestines of non-breastfed children are more likely to stimulate the immune system and thus also lead to an overreaction that is directed against actually harmless food components.
Is dysbiosis a cause of irritable bowel syndrome?
The stool of irritable bowel patients shows less diversity of bacteria than the stool of a healthy person - some groups of bacteria seem to multiply particularly strongly in this disease. What exactly this means for the development and treatment of the disease is not yet known. One theory is the idea of mild intestinal inflammation, already described above, triggered by improper colonization. Studies that research the therapeutic success of microbiome probiotics could test these presumptions.
What other diseases are related to dysbiosis?
Dysbiosis is associated with many other diseases without clear cause-and-effect principles being identified. Researchers hope, however, that diseases such as depression, chronic fatigue, rheumatism and chronic pain can be examined more closely through the intestinal flora, and be explained better.
How can dysbiosis be diagnosed?
The composition of the microbiome can be determined from a stool specimen. However, many intestinal bacteria cannot be grown conventionally. For this reason, the heritage of the different bacteria can be detected directly. This process is currently very expensive. Since it is not yet known which bacteria have which effect and which treatment options could be derived from the findings, microbiome analysis has so far not been recommended for routine care. However, it is used in research.
If there are symptoms that suggest, for example, a chronic inflammatory bowel disease (such as bloody diarrhea and abdominal pain), these should primarily be clarified conventionally. That means, for example, a colonoscopy or a test for food allergies is carried out. Dysbiosis does not have to be diagnosed in this context, but is very likely based on the disease. For this reason, therapeutic measures can also be initiated without the need for an extra stool analysis.
How can dysbiosis be avoided and treated?
Limit antibiotic intake
Both prevention and treatment of dysbiosis focus on enhancing beneficial influences and limiting harmful influences. For example, everyone should critically question the use of antibiotics. However, if there is a strong suspicion of bacterial infection, these potent agents are still essential. It should then be ensured that the correct dose is taken over the entire prescribed period.
Breastfeeding helps against dysbiosis
Because breastfeeding has an unequivocal and long-lasting positive influence on the intestinal flora, if at all possible an infant should receive breast milk for the first four months of life at least. Many women experience breastfeeding problems during the first weeks of their newborn's life. However, this should not automatically lead to a switch to formula food; good breastfeeding advice can help most mothers. Even if only partial breastfeeding is possible and the child receives additional powder milk, this has a protective effect on the intestinal flora and the child's immune system. In addition, breastfeeding helps the mother and child to establish a deep connection.
Balanced diet against dysbiosis
Since nutrition has an impact on the microbiome, there are recommendations that would favor a healthy bacterial composition. Food should not contain too much fat and sugar and should be high in dietary fiber. Dietary fiber is found, for example, in whole grains, especially from rye, and vegetables. Raw food, with the exception of leafy greens, should be avoided with acute dysbiosis. Stone fruit is also not ideal during dysbiosis. Flatulent foods such as cabbage or legumes should be avoided.
Prebiotics for dysbiosis
If dysbiosis is suspected, prebiotics and probiotics can be used to bring the intestinal flora back into balance. Prebiotics consist of substances that stimulate the growth of the "good" intestinal bacteria, while probiotics directly contain health-promoting microorganisms. Sauerkraut and yogurt are beneficial, for example, but probiotics are also available as food supplements in pharmacies.
Stool transplant for dysbiosis
In extreme dysbiosis cases such as pseudomembranous colitis from candida albicans, stool transplants have proven succesful (Fecal Microbiota Transplantation, FMT). Faeces from a stool donor are washed up with liquid and brought into the patient's stomach through a gastric tube or during a colonoscopy. The theory is that health-promoting bacteria can resettle in the intestine. The transplant has not yet been approved for any other diseases, but there are experiments that have tested the treatment for Crohn's disease and irritable bowel syndrome. In alternative medicine, so-called “gut renovations” are carried out by ingesting the affected intestinal bacteria in capsules. So far, however, no studies have shown the success of these methods, which is why the procedures are usually not covered by the health insurance companies.
What should be considered when treating dysbiosis?
Treatment for dysbiosis can make a positive contribution to improvement in certain diseases. However, at the current time it should not be the only therapy used, because it is still unclear what proportion it has in the development of which diseases. It is therefore still important that diseases such as inflammatory bowel disease, diabetes or depression should be treated by a doctor. Dysbiosis treatment can then be carried out at the same time, for example with the help of naturopaths.