The pharmacist has probably offered you probiotics at some point to avoid the unwanted effects of antibiotics. Or perhaps they have recommended that, instead of so much pharmacy product, you drink several yogurts a day – or kefir – so as not to feel unwell if you have been prescribed medication. What is true in all this?
The antibiotics that we use to combat infections caused by pathogenic bacteria are a double-edged sword, since they can also kill beneficial bacteria from the so-called intestinal microbiota, causing, above all, diarrhea.
Additionally, these drugs can eliminate “good” bacteria and produce an imbalance in the microbiota. In this case, fungi of the genus Candida They can take control of the genital area, for example, and cause uncomfortable vulvovaginal candidiasis, which manifests itself with itching and irritation.
What are probiotics?
The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) have jointly defined probiotics as “live microorganisms that, when administered in adequate quantities, confer a health benefit to the human body.” Guest”.
They are available in pharmaceutical preparations, in food supplements or, naturally, in certain foods, whether fermented or not. They can even be added later to these foods.
Bacteria of the genus Lactobacillus either Bifidobacterium They are the most used, but not the only ones, and the doses at which they are effective depend on each specific probiotic. This needs to be established through human clinical studies.
The three commandments that must be fulfilled
The very definition proposed by the WHO and FAO implies three important factors: microorganisms have to be alive at the time of consumption, cause no harm and provide a proven beneficial effect on human health.
The first point is controversial, since the bacteria may be alive when taken, but it is not clear that they survive the acidic pH of the stomach or the enzymes of the intestine. Secondly, and although in principle they are safe, ingesting live bacteria can pose a health risk to susceptible individuals, those with serious illnesses or who are immunocompromised.
Regarding the third point, there are a large number of clinical scenarios in which probiotics have proven effective, always depending on the dose and the situation. In the case at hand, they have shown a moderate protective effect in children, adults and the elderly to avoid diarrhea associated with antibiotics.
Efficiency… with nuances
But surprisingly, the effect of probiotics is not widespread. There seem to be “resistant” people who eliminate these microorganisms after ingestion without receiving any benefit or harm. On the other hand, the so-called “persistent” people do notice their effects, avoiding the loss of biodiversity caused by antibiotics.
And this is the subject of debate: probiotics can change the microbiota so that it is no longer the same as before starting antibiotic treatment. They can even make it take us longer to recover our original microbiota.
Furthermore, the use of vaginal probiotics in genital infections due to Candida doesn’t seem to help. In this case, only a good antifungal treatment is effective.
Yogurts: a source of live bacteria
Regarding the use of yogurts and other fermented products, it is important to know that in Spain you can only call “yogurt” a coagulated milk product obtained by lactic fermentation through the action of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, as established by a Royal Decree. In addition, each gram or milliliter must contain a minimum of ten million live bacteria.
From this it follows that the so-called “pasteurized yogurts after fermentation” are contemplated in the legislation with that small nuance, since the bacteria they contain are killed by the thermal effect of pasteurization.
À lire also: Guide to choosing the healthiest yogurts
If we do the math, a 125-gram “authentic” yogurt includes 1.25 billion live bacteria, which gives an idea of how many “good” microorganisms we ingest if we eat several a day. Its bacteria seem to have multiple beneficial effects, although many times, as with probiotics, it is a matter of dosage.
Finally, it should be noted that the direct application of yogurt to the genital area has little or no use against vulvovaginal candidiasis.
L. casei and bifidobacteria: is what the ads say true?
Some fermented dairy products contain other bacteria that could help, although with certain nuances. This is the case of products that incorporate the bacterial species Lacticaseibacillus caseiadvertised as favorable for our immune system.
Although some studies claim that they reduce the incidence of diarrhea associated with antibiotics, the European Food Safety Agency (EFSA) refuted this in a report. In reality, the person responsible for this benefit is not L. casei, but vitamin B6 that also incorporates this type of dairy product in its composition. B6 is found naturally and in great abundance in bananas, for example.
Something similar happens with dairy products enriched with bifidobacteria, which, according to advertisements, improve our digestive health and make us feel good. It does seem that eating yogurt with certain strains of this bacterial genus reduces the problems associated with taking antibiotics, but it depends on each specific strain of Bifidobacterium with which the dairy is supplemented.
And finally, what about fermented foods like kombucha, kimchi, sauerkraut or kefir? Well, mainly because they do not have an exact and defined composition of microorganisms, unlike yogurt or commercial probiotics. In this case, its effects will be conditioned by the composition of each product and nothing can be taken for granted.
