Is it true that dysbiosis as a diagnosis does not exist, and probiotics are useless?

Both doctors and patients attribute numerous problems with the gastrointestinal tract to dysbiosis. The main method of treatment in this case is the administration of probiotics, which are designed to populate the intestines with beneficial bacteria and relieve the patient of unpleasant symptoms. Especially often, a course of probiotics is prescribed in parallel with antibiotic treatment. We decided to check whether such actions are justified from a scientific point of view.

Dysbacteriosis is one of the most popular diagnoses among therapists and pediatricians. They tend to explain not only problems with the stomach and intestines, but also diseases such as bronchial asthma, allergies, psoriasis, acne, and also headache, dullness of hair and brittle nails, rapid fatigue, decreased concentration and surges in blood pressure. One of the most common causes of dysbiosis think taking antibiotics, since while they fight pathogenic bacteria, they also kill the “good” ones. Therefore it is enough often doctors prescribe along with a course of antibiotics and probiotics. Various probiotic, prebiotic And eubiotic supplements are available in a wide range of pharmacies and are available without a prescription. Also populate intestines with beneficial bacteria promise producers of yoghurts and other fermented milk products and even toilet paper.

In the post-Soviet medical space, dysbiosis is usually understood as a certain change in the composition of bacteria in the large intestine. However, in foreign practice, in particular in the International Classification of Diseases (ICD-10), such no diagnosis. Candidate of Medical Sciences Vladimir Vasilenko counted, that “by searching the global medical scientific database Medline using the keyword dysbacteriosis, we learn that it is present in the titles of 257 scientific papers published from 1966 to 2000, 250 of them in Russian-language medical journals, another four belong to authors from the former socialist camp.”

Moreover, although in Russia there is row laboratory analyzes (for example, stool culture for dysbacteriosis and analysis of microbial markers using gas chromatography-mass spectrometry according to Osipov), designed to confirm or refute the patient’s diagnosis, practitioners of evidence-based medicine question their methodology and results. Alexey Golovenko, Candidate of Medical Sciences, gastroenterologist, explains: “The norm for them was invented according to some unknown principle several decades ago.” He also comments on the history of the creation of the diagnostic: “[The scientist] first identified a group of people allegedly with dysbacteriosis by stool culture, and then conducted a blood test on them. That is, this is an assumption on an assumption. And it’s difficult to call this analysis anything other than an anti-scientific pumping of money from the population.”

The pointlessness of such analyzes is also speaks out Tatyana Tikhomirova in the column of the authoritative scientific publication “Popular Mechanics”: “The fact is that intestinal bacteria mainly live not in its lumen, but on a thin film on the intestine itself. In this case, only those who die, those who are unlucky, do not have enough space, or a small part of those bacteria that, for some reason, prefer the lumen, break away (and end up in the lumen). And the analysis for dysbacteriosis takes into account only those bacteria that live in the lumen. Recently, the DNA of microbes taken through biopsies of the intestinal wall was analyzed. It was discovered that more than 75% of all inhabitants had never been cultivated at all!”

The lack of recognition of the disease in other countries, questions about the methodology of tests and the interpretation of their results, as well as insufficient knowledge of microorganisms of the colon leads us to the conclusion that the concept of “dysbacteriosis” can't be diagnosis. At most, this word can characterize some violations without indicating the reason for their occurrence. This is precisely the danger of a doctor making such a diagnosis based on patient complaints. Specialists evidence-based medicine notes that in this way much more serious diagnoses may be missed and not identified: irritable bowel syndrome, Crohn's disease, lactase deficiency and even cancer.

The most frequently prescribed groups of drugs when diagnosed with dysbiosis are probiotics (contain beneficial bacteria in dried or dissolved form), prebiotics (not digested or absorbed in the upper gastrointestinal tract, but are fermented by the microflora of the large intestine and stimulate its growth and vital activity) and eubiotics (live microorganisms and their metabolic products that have normalizing effect on the composition and biological activity of the microflora of the digestive tract). The same names are used in advertising of all kinds of biologically active additives (BAS), as well as “live” yoghurts and other food products “for the intestines.”

The division of bacteria into beneficial and harmful is very arbitrary. First, the qualitative and quantitative composition of bacteria in the large intestine varies depending on where a person lives. Finding yourself in an unusual environment is precisely are explained problems with the gastrointestinal tract that arise during travel. Secondly, as mentioned above, the composition of the intestinal microflora has not been sufficiently studied. Finally, thirdly, in 1 g of colon contents lives about 10¹¹ — 10¹² bacteria. The content of bacteria in dietary supplements, tablets or yoghurts is several times less. Moreover, most of, for example, lactobacilli coming from food, destroyed hydrochloric acid in the stomach for four hours. It is worth noting that the probiotics market is huge: in 2017 it amounted to more than $1.8 billion, and by 2024, according to economists’ forecasts, will reach $66 billion. At the same time, the drugs do not have proven effectiveness, and in some cases they do more harm than good.

A group of Israeli scientists studied the need to use probiotics as part of antibacterial therapy. Dividing patients taking antibiotics into three groups, the scientists assigned one group probiotics, the second group an autotransplantation (transplantation into oneself) of feces taken from them before treatment, and the third group did not take anything other than the antibiotic therapy itself. The second group demonstrated the fastest restoration of intestinal microflora. However, the group that took probiotics recovered worse than the group that didn’t take anything.

They didn't provide probiotics have a healing effect on children with gastroenteritis. The study involved 886 children with gastroenteritis aged from three months to four years. Some of them received probiotics, and some received a placebo. It turned out that in the probiotic group, 26.1% of subjects had a moderate or severe course of the disease over a two-week period, and in 24.7% of the placebo group. However, in terms of symptoms (diarrhea and vomiting) there was no difference at all. There are separate cases, when taking probiotics contributed to fungemia - the spread of a fungal infection in the patient’s blood. 

IN systematic review In a 2016 randomized controlled trial of probiotics, researchers found no effect of probiotics on the gut microbiota of healthy adults. There are some short-term studies showing the effectiveness of certain groups of bacteria. For example, taking Lactobacillus casei Shirota showed among patients with chronic constipation, there was an 89% improvement versus a 56% improvement in the placebo group. However, as the researchers note, a probiotic is not a complete treatment, but only an addition to it.

With prebiotics—essentially food for bacteria—the situation is more clear. There is no evidence of their proven benefit in the treatment or prevention of any diseases. Infectious disease specialist Dmitry Troshchansky explains: “Prebiotics are mainly carbohydrates, which are found in many vegetables and fruits; buying them in pharmacies is pointless.” Agree with him is Alexey Golovenko, candidate of medical sciences and gastroenterologist: “No one has yet proven that taking them is healthier than eating, for example, two kiwis a day or replacing white bread with whole grain bread, eating less sweets and more fruits and vegetables.”

Eubiotics - supposedly living organisms inside dietary supplements or yoghurts - will not cure a dozen diseases. Firstly, up to 90% of living bacteria in them don't survive before reaching our table. Secondly, most of the “survivors” will be dissolved by hydrochloric acid, which is part of the gastric juice. And those units that do get into the large intestine will be so weakened that they will not be able to withstand its “indigenous” inhabitants. 

At the same time, it is not worthwhile to completely classify probiotics as “fuflomycins”. Eran Elinav from the Weizmann Institute (Israel) predictsthat with the increasing availability of creating a patient’s genetic profile, they can become personalized medicines, that is, made specifically for each patient and effective only for him. In a similar way describe the future of probiotics and prebiotics in the journal “Trends in Microbiology”, but, unfortunately, today the pharmacological industry does not have such individual developments.

Thus, dysbiosis cannot be considered a full-fledged diagnosis and all symptoms cannot be attributed to it. In most cases, when taking antibiotics, prescribing probiotics is pointless and sometimes unsafe. It also makes no sense to overpay for “live” yoghurts and dietary supplements in the hope of getting rid of a number of health problems at once. The vast majority of products that promise to populate the intestines with beneficial bacteria are simply a marketing ploy to increase sales.

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What do our verdicts mean?

Read on the topic:

1. Is it true that there are more bacteria in the human body than cells of the body itself?
2. Do probiotics help restore intestinal microflora?