Probiotics labeled "totally useless" – BBC News

A group of scientists in Israel say that foods containing good bacteria – called probiotics – are almost useless.

Their study is one of the most detailed analyzes of what happens when we consume probiotics.

They are considered healthy and good for the intestines, but the results showed that they had little or no effect inside the body.

The researchers said that probiotics of the future would require adaptation to the needs of each individual.

The Weizmann Institute of Science team created its own probiotic cocktail using 11 common good bacteria, including Lactobacillus and bifidobacteria.

It was administered to 25 healthy volunteers for a month.

They were then sedated and specimens were surgically removed from several locations in the stomach and small and large intestines.

The researchers sought to find out where the bacteria colonized successfully and whether they caused changes in the activity of the intestine.

The results in the journal Cell, showed in half of the cases that the good bacteria entered the mouth and left the other side.

In the rest, they lingered briefly before being squeezed out by our existing microbes.

The microbiome

• You are more microbe than human – if you count all the cells in your body, only 43% are humans
• The rest is our microbiome and includes unicellular bacteria, viruses, fungi and archaea.
• The human genome – the set of genetic instructions for a human being – consists of 20,000 instructions called genes
• But add all the genes in our microbiome together and the number is between two and 20 million microbial genes
• It is known as the second genome and is linked to diseases such as allergy, obesity, inflammatory bowel disease, Parkinson's disease, if cancer drugs are acting and even depression and autism.

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Billions of bacteria call the wall of our entrails and everyone has a different mix of microbial inhabitants.

Dr. Eran Elinav said that it was wrong to expect that a standard probiotic works for everyone.

He says that in the future, probiotics will have to be tailored to the needs of each patient.

He told the BBC: "And in that sense, buying probiotics at the supermarket without any adjustment, without any adjustment of the host, at least in part of the population, is quite useless."

The research group also examined the impact of probiotics after a series of antibiotics, which eliminate both good and bad bacteria.

Their 46-person trial, also in the journal Cell, showed that this led to delays in the recovery of normal healthy bacteria.

Dr. Elinav added: "Contrary to the current dogma that probiotics are harmless and benefit everyone, these results reveal a new potential adverse effect of using probiotics with antibiotics that could even have consequences at the same time. long term".

Probiotics have some advantages, especially to protect premature babies against necrotizing enterocolitis.

And there remains great hope in the science that understanding the complex relationship between the microbial and human parts of our body will lead to new treatments.

However, Dr. Trevor Lawley, a microbiome researcher at the Sanger Institute, said he was not surprised by the results.

He told the BBC: "Probiotics have been around for a long time and are undergoing more scrutiny.

"These are very innovative studies, but these are preliminary results that need to be replicated.

"The intestine has a natural property to stop colonization because it usually blocks pathogens, and that's something we need to thwart."

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