Probiotics don’t work as advertised

To be sustainable, probiotic bacteria should settle in the gut — but they do it not all people. After antibiotic treatment, they can even disrupt the normalization of intestinal flora.

Пробиотики не работают так, как рекламируется

Say that probiotics improve intestinal health or immune system. They sold millions of times in the form of capsules, powders or fortified products, although many scientists and EFSA European food klassificeret the action of bacteria used as not proven. However, two new studies not only cast doubt on the effectiveness of probiotics, but also reveal new adverse effects after antibiotic therapy, writes NZZ.ch.

Bacteria “rush”

To have a really long-term positive effects on the body, swallowed bacteria to settle in the intestine. But that is exactly what is happening with each consumer of probiotics, the researchers from Eran Segal and Eran Elinav of Warminsko Institute of science in Israel. Rather, there are people who have swallowed the bacteria just “break”, because their own intestinal flora actively prevents implantation.

This is demonstrated by the study, fifteen healthy people who were taking a regular probiotic for four weeks. Before and three weeks after the first dose small pieces of the intestinal mucosa were taken from endoscopy at several points in the gastrointestinal tract. As expected, germs from the capsules was detected in the stool samples of all the subjects. But only six people, researchers were able to detect probiotic germs in the intestinal mucosa and thus the integration in the native flora. Their prevalence was variable and did not correlate with the amount of probiotics in stool samples.

About positive effects in previous studies

According to the researchers, these results may also explain why some previous studies found a positive effect of probiotics.

First, in the past have analyzed only samples of chair. But their composition is apparently only nominally was slightly higher than the composition of the intestinal mucosa. Precise genetic analyses of the intestinal flora can be done only within a few years.

Secondly, to detect differences between resistant and susceptible individuals is possible only if individually and separately to evaluate the status of intestinal flora before and after, the researchers write. Presumably, these two shortcomings in the previous research led to some about the effects of probiotics. However, new research no doubt. The number of participants was small and the researchers used only one probiotic. In addition, it was not checked whether the positive effect of the probiotic, which was observed in subjects. But if swallowed, the bacteria do not remain in the intestine, it is difficult to imagine that they will have value.

The intestinal flora to normal later

However probiotics not only accept healthy people. They also recommended for patients to prevent diarrhea or other gastrointestinal symptoms during antibiotic therapy. But in these situations, probiotics can even be counterproductive, as shown by Israeli researchers.

Twenty-one people attended the two common antibiotic for seven days. Subsequently, seven of them were exhausted, eight, took a probiotic, and six received a transplant from their own intestinal bacteria, which had previously been collected. In the latter case, the intestinal flora was again intact the day after the transplant. Without any intervention it took about three weeks to return to normal life.

In probiotic group of bacteria are now successfully nesting in the intestinal mucosa of all subjects, in the end, now they had a clear path. However, genetic analysis showed that the initial condition of the intestinal flora has not returned in five months. The authors write that probiotics has slowed the recovery of the intestine.