Probiotics, not as good as advertising says
Are probiotics effective or not? Researchers from Israel analyzed them thoroughly and concluded that they do not always fulfill their harmless reputation, and to be effective, they should be adapted to each individual.
Antibiotics have transformed medicine and the fight against bacterial infections. But everything has a price and its consumption, more and more widespread, is associated with a variety of gastrointestinal effects.
Between 5% to 35% of patients treated with antibiotics develop a problem. This is because the medication not only stops the bacterial infection but also completely alters the microbiome, that is, the population of bacteria that live inside the digestive system.
In response to this challenge, "probiotics", compounds with "good bacteria" with which the microbiome of patients is expected to repopulate, appeared on the scene. The boom of these products has even reached the supermarkets where you can buy dairy products, mainly yogurts, enriched with probiotics. The promise is always the same: to improve the population of bacteria in our digestive system.
But do probiotics really work? A group of researchers from Israel, headed by Jotham Suez, carried out one of the most complete evaluations on the subject in which they analyzed the performance of probiotics in mice and humans.
The results have just been published in the journal Cell and are a blow to the promoters, and consumers, of these products.
"The study shows that the alleged protection induced by probiotics from the adverse effects associated with antibiotics may not be without risks," the scientists noted.
Like any other medical treatment, they concluded, their potentially beneficial pathogen repellent activity (which remains to be proven or refuted) can carry a risk of impact that adversely affects the rate and degree of recolonization of the individual's oriniginal bacteria.
By studying the bacteria in the faeces of individuals who participated in the study and also those who lived in the intestine, the scientists discovered that while probiotics colonized the gastrointestinal tract of some people, the gut microbiome of others eventually expelled them.
"Some people accept probiotics in the intestine, while others simply pass them from one end to the other," said immunologist Eran Elinav of the Weizmann Institute of Science in Israel to New Scientist magazine.
The main contribution of the work is that apparently the patterns of probiotic colonization, the "good bacteria", are highly dependent on the individual and therefore their effectiveness is not guaranteed. The concept that everyone can benefit from a universal probiotic purchased at the supermarket "is empirically wrong," the authors said.
When comparing patients who received probiotics with a group that did not receive them after antibiotic treatment, the scientists were surprised. "Probiotics prevented the original microbiome from returning to its original situation very powerfully and persistently," Elinav tells New Scientist magazine. "This was very surprising and alarming for us, this adverse effect has not been described to date
