It probably happened to you. The doctor prescribes antibiotics and the pharmacist who sells them recommends probiotics so that the medicine does not destroy your stomach.
Probiotics are microorganisms present in certain foods (especially some yogurts and cheeses), and are used to make tablets and drinks that – supposedly – help us to regain the balance of the intestinal flora and thus make our digestive system work well . They are also credited with the ability to strengthen our defenses, and many other benefits that two investigations published in the journal Cell now question.
They have been made by a team of researchers from the Weizmann Institute of Sciences in Israel, who have found that the gastrointestinal tract of many people resists being colonized by probiotics of external origin, and that taking probiotics to counteract the effect of antibiotics can delay the return of the intestinal flora to its state prior to taking the drug.
Eran Elinav, an immunologist at the Weizmann Institute, notes that “the results indicate that the probiotics that we buy in the supermarket do not work as we think, and that they should not be sold as a valid product for everyone. They would have to be tailored to the needs of each individual ”.
Direct to the intestine
In this case, the Israeli researchers changed the usual method of gut flora analysis. Instead of analyzing the excreta of the 25 volunteers participating in the first study, they observed in situ the bacterial colonization of their gastrointestinal tracts, through endoscopies and colonoscopies that, together with genetic studies, served to know the characteristic microbiota of each subject.
15 of the volunteers were divided into two groups: the first took generic probiotics, and the second a placebo. They then went through another round of endoscopies and colonoscopies and were followed for two months. The results showed that the effectiveness of probiotics depended on each person: some had intestinal flora prone to external help, but in others the opposite was true, so taking probiotics was of no use to them.
Antibiotics at stake
In the second study, the scientists analyzed what happened when 21 volunteers who were on antibiotic treatment took probiotics to counteract the harmful effects of those on the intestinal flora, something that many doctors and pharmacists often recommend.
In this case, conventional probiotics colonized the intestines previously cleaned by antibiotics, which eliminate pathogens but also beneficial bacteria, but unexpected collateral damage was observed: probiotic colonization prevented the return of the intestinal flora of each individual to their state for months. normal, marked by genes and environmental conditions, especially those of the first years of life.
According to Elinav, “Against the current dogma that probiotics are safe and benefit everyone, these results reveal that taking them in combination with antibiotics has a potentially harmful long-term effect. Repopulating the intestine with the microbes themselves through a personalized treatment may be better ”.
