Truths and lies about probiotics, the live microbes everyone wants to take

Probiotic means pro-life. A whole linguistic hyperbole that has motivated the business around the term to go ahead with research, in pursuit of the good health of the income statements of those who produce them. Today, in addition to milk and yogurts, you can find shampoos, shaving lotions, disinfectants, serums, facial cosmetics , dandruff pills and toothpastes that claim to contain live microbes that ensure good health. of the staff. “The problem is that everything is being put in the same bag: those uses supported by clinical trials and others that are not,” explains Dr. Francisco Guarner, president of the Spanish Society of Probiotics and Prebiotics (SEPyP)and a world reference in this area. “The manufacturer who has gone to great lengths to show that their product is beneficial when administered in the right amounts is on pharmacy shelves at the same height as other compounds where it is not known what is inside, because the Companies that launch them have not bothered to carry out a study on their efficacy, “warns the also senior researcher at the Research Institute of the Vall d´Hebron University Hospital in Barcelona. “This has had an impact on whoever was doing research has stopped doing it,” he regrets.

The main problem is that they are not medicines

As a result of this “anything goes”, many so-called probiotics (who provide no proof of their benefits) take fame (credibility and money), while those backed by solvent studies are placed under suspicion (on top of that they card the money…). “There is a great need for new, well-designed and conducted trials to explore the potential for supposedly improved health for healthy people,” Oluf Pedersen, author of a meta-analysis published in the journal Genome Medicine, acknowledged as early as 2016.which ensures that two of the probiotics most used by the food industry (lactobacilli and bifidobacteria) had no effect on the intestinal flora of individuals without pathologies, the main group to which its advertising is directed.

More recently, on October 22, 2018, The New York Times recalled in an article titled The Problem With Probiotics, that as dietary supplements they are are much less strictly regulated than medications, so they do not need to demonstrate their efficacy. to be marketed, but only its safety. As a consequence of this regulatory laxity, some manufacturers have based their commercial strategy on offering high profit margins to pharmacists and the rest of the sales channels, instead of airing the effect of their bacteria when compared to placebo. Powerful marketing deployed by this buoyant industry has made consumers fall in love with probiotics (which, in addition to being integrated into food, are available in pills, syrups or sachets), to the point that, according to Forbes magazine, almost 4 million Americans use them. they consume today, moving today 45,000 million dollars (about 40,000 million euros) and promoting a world market growth of 7%.

And they don’t seem effective in healthy people

Parallel to the good progress of the sector, more than 16,000 scientific investigations have tried to elucidate in the last 30 years whether its consumption has a reflection on the quality of life of users. As dietitian-nutritionist Julio Basulto explains, “In January 2016, NHS Choices, the UK’s largest healthcare portal, thoroughly reviewed existing studies to separate grain from chaff. The summary, it could be, is the proven benefits They involve a small number of disorders related to the digestive system, such as traveler’s diarrhea, irritable bowel syndrome and diarrhea in children who took antibiotics. On the other hand, it has not been possible to confirm its efficacy for most of the conditions for which they are also prescribed, such as strengthening the immune system, losing weight,“As for yogurt (the fermented star food – that is: with friendly microbes -), NHS Choices believes it may be good for people who are lactose intolerant, as well as certain strains of probiotic bacteria that may mitigate symptoms of the syndrome. of irritable colon or ulcerative colitis, although the researchers agree that “more studies are needed to recommend them.”

Many experts draw a dividing line between the improvements they produce in patients, about which there are some well-designed clinical trials, and those that presumably work in people who are in good health, in which case the evidence to recommend their use is more diffuse . The underlying theory is that for the latter, taking a probiotic makes the same sense as an antibiotic when you are not sick. “It can be a complement to the treatment, but not the solution itself, since this requires going to the root of the problem, which can be as much in a bad diet as in excessive stress or sedentary lifestyle,” says the dietitian-nutritionist Jesús Sanchis, member of the Spanish Academy of Nutrition and Dietetics.

Regarding how we eat: “What is being seen, in any case, is that the type of diet we eat today is not healthy for the intestinal microbiota, since it lacks fiber and polyphenols,” stresses this expert, co-author of the Prebiotic feeding book (Platform). Thus, to prevent digestive pathologies, before the probiotic, good guidelines are imposed on the table. And, practically, from the first minute of life. “The window of opportunity for the microbiota [when our flora is formed, which will determine many ailments to come] is located from gestation to three years of age; and includes childbirth, the type of lactation (ideally it should be maternal) and the first foods “, ditch Sanchis.

Bacteria that do some good may not serve others

Two studies published in the journal Cell in the past year have thrown more fuel on the fire. In the first, researchers from the Israel Weizmann Institute of Sciences found that the external bacteria supplied by probiotics do not affect a large part of the population. In the second article, the same scientists wanted to analyze how these affect the intestine when taken to counteract the effect of broad-spectrum antibiotics: thus, they observed that the treatment interfered with the return to normality of the patient’s microbiota instead of speed up your recovery, as initially believed.

Both trials have been widely criticized by the International Scientific Association for Probiotics and Prebiotics (Isaap), due to their methodological gaps. A possible conflict of interest of the authors has even slipped, since they are promoting a private company that promotes the same type of personalized approach to probiotics suggested by Cell’s two scientific articles , from which it seems to be deduced that buying any probiotic product in the supermarket that does not fit the particular microbiome of the consumer is throwing money away and wasting time.

Francisco Guarner, as representative of the scientific community working in this field, raises two other objections to the research. The first is that although probiotics do not modify the microbiota, this should not be interpreted as that they do not work inside the intestine, and uses yogurt as an example: “Although bacterialive are annihilated by stomach acid, this does not prevent the opening and release of an enzyme called lactase that helps digest lactose to approximately 15% of Spaniards who have problems breaking down milk sugar. “The criterion used to serve The WHO or the FAO, “is not that the probiotic adheres to the intestinal mucosa, but that it takes effect”, recalls Guarner, who also chairs the International Consortium of the Human Microbiome (IHMC), an organism dependent on the European Commission.

However, there is no shortage of dietitians-nutritionists who argue that even this supposed probiotic effect of yogurt (which, in theory, allows lactose to be digested by people who cannot tolerate it) does not obey the microorganisms and bacteria provided by the food, but rather , simply, that a glass of milk is 200 milliliters and a yogurt 125, that is, half, to which it must be added that this is taken more slowly. However, while there is little evidence that probiotics have a significant impact on the overall structure of gut microbial communities of healthy subjects, beyond the transient increase in the specific strain consumed, there is some evidence to suggest that they may have effects. beneficial without colonizing the gastrointestinal tractor subsequently alter the composition of the faecal microbiota. Guarner’s second objection is that the Cell authors did not administer the probiotics at the same time that the participants began to be treated with antibiotics, as usual, but did so afterwards, which could explain why they did not take effect at the time of restore the microbiome.

It is clear: it will be one of the next great revolutions

Growing discredit affecting probiotics, which have echoed headers of the prestige of the BBC, the CNN or The Guardian, is a direct cause not to require companies producing the same requirements as scientists(that is, that they are, in fact, living microorganisms; that they are in the adequate quantities; that they are characterized at the level of genus, species and strain; that their standard is deposited in an international collection so that the manufacturing company is in a position to guarantee that the strain does not evolve and is always the same one that appears in that collection; that it has double-blind studies that demonstrate its efficacy in people and not only in animals …) And it coincides, paradoxically, with other new lines of research very promising: to date, the vast majority of studies that have been carried out with probiotics have focused on acute processes (diarrhea or constipation),for being much faster and considerably cheaper. In contrast, there are very few long-term investigations because they are more difficult and expensive. According to specialists in this field, the future may lie on that path.

In fact, an increasing number of experts agree that some of the most hopeful research is focused on the gut microbiota. Very synthetically, it is beginning to be seen that many diseases associated with the western lifestyle have chronic inflammation and defects in the microbiota as a common pattern, which could give rise to new, much more specific probiotics depending on the individual microbiome, which replace the current universal or one size fits all probiotics.

According to Guarner, there are lines of researchvery attractive about the relationship that maintains the long kilo of microorganisms – basically bacteria, but also viruses, fungi and yeasts – that each person harbors in their intestines, with the regulation of the immune system and the approach to various types of cancers and melanomas; but also with the treatment of central obesity and the central nervous system. The president of the SEPyP refers, for example, to a study carried out by Canadian researchers among a group of patients with irritable bowel who also presented a picture of depression. When evaluating their intervention, they found that the probiotic they used was more effective in alleviating mental pathology than in reducing abdominal pain. Therefore, after the study was published in a reference scientific journal,

The question floating in the air is: Will correcting these microbiota defects improve the prognosis for many diseases? “Right now it can’t be known,” answers Guarner, “since there is a lot of data in animal models, but very few studies in humans.” In other words, although the knowledge of the microbiome is still very scarce, its potential is revolutionary. Waiting for that promising future, something seems clear: doing applied research (that is, the marketing department using pseudoscientific terms as a sales argument) is not the same as applying it to research so that the sector has credibility.


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