The World Health Organization defines probiotics as live microorganisms that, when administered in adequate amounts, confer a benefit on the health of the host. However, substances produced by microorganisms and their constituents can not be considered as probiotics, even though these elements have biologically beneficial effects on the consumer.
What are probiotics?
Probiotics can be part of the composition of different types of products, including foods (functional foods), medicines and dietary supplements.
For a microorganism to be qualified as probiotic, it must meet a series of requirements, among which include:
- Be correctly identified. It is required that the identification be at the level of genus, species and strain, by means of phenotypic and genotypic methods, given that the beneficial effects demonstrated in a specific strain are not extrapolated and attributable to another strain of the same species. It is also required that the strain be deposited in internationally recognized collections.
Probiotic Acidophilus Dietary for Digestive Health with Friendly Bacteria, 3 Bottles (200 Count)
- Lack of virulence factors and / or ability to produce undesirable metabolites for the host, a requirement that greatly reduces the candidates to exercise this role. It is true that there are many bacteria that naturally colonize the mucous membranes of the human being and that provide a benefit to the host and therefore could potentially be considered as probiotics; However, it is also true that the vast majority of them are capable of causing infectious processes in certain states. As an example of this, we can mention Escherichia coli , a bacterium that is usually colonizing the colon. There is a strain of this species with proven efficacy as a probiotic; However, there are other strains of this same bacterial species that, if passed to the peritoneal cavity or to the blood, can generate serious infectious processes, and another group of strains of E. coli capable of producing toxins that induce diarrhea, dysenteric processes and whose genes they can be easily transmitted to innocuous strains, so their use as a probiotic would be compromised.
- In practice, the probiotics accredited as such come from the ferments used in the fermentation of food, and are mainly lactobacilli and bifidobacteria, since they do not include pathogenic strains within the species to which they belong. These microorganisms have been recognized as GRAS organisms ( Generally Recognized As Safe ) and QPS ( Qualified Presumption of Safety ) by the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA).
It is also cataloged as probiotic Streptococcus thermophilus , microorganism with proven activity in the improvement of lactose digestion in individuals intolerant to this disaccharide.
- Demonstrate scientifically, through clinical trials in humans, the beneficial effects on the health of the host and the safety of the microorganism that produces them, beyond the benefits inherent in basic nutrition. Laboratory studies in vitro or / and in animal models, although they are necessary for obtaining information on the mechanisms of action, identification of target functions and biomarkers, are not considered sufficient evidence of efficacy in human health. A clinical evaluation in humans will always be required through double-blind, randomized, and placebo-controlled trials.
- Show tolerance to environmental conditions where they exert their action and remain viable and functionally active in the gastrointestinal tract. For this they must be resistant to destruction by gastric secretions and bile, and must have the ability to adhere to the intestinal epithelium, as well as to colonize the gastrointestinal tract, even for short periods of time.
- To be in sufficient quantity to be able to exert the desired effect. This amount is usually very high, in the order of one hundred to one billion colony-forming units (CFU) per dose.
- Incorporated microorganisms must be viable in the products to which they are incorporated. They must be resistant to the conditions of processing, conservation and maintain their viability in sufficient quantity during the useful life of the product in which they are administered.
How do they act?
Scientific endorsement of the mechanism of action of probiotics is essential so that they can be accredited as such. Depending on the selected strain they can act in the host at different levels.
In the intestinal lumen
- Through direct interaction with the intestinal microbiota . Probiotics modulate their composition either by inhibiting pathogenic microorganisms or by favoring the presence and diversity of bacteria considered beneficial within the intestinal ecosystem.
The intestinal microbiota has a great influence on the digestive health and the immune system and, by extension, on the general state of health of the individual; intervenes in a large number of essential functions for the proper development of the person and that is why this ecosystem must self-regulate and stay in balance. The intake of probiotics is able, by reducing the pH of the medium and the production of antibacterial compounds (bacteriocins, hydrogen peroxide), to reduce the adherence, replication and action of the flora potentially pathogenic to the host.
- Exercising direct metabolic effect . The modification of the intestinal flora through the ingestion of probiotics involves the modification of some of the metabolic functions that it exerts, among which we can mention: absorption of certain nutrients, degradation of non-digestible material of the diet, regulation of energy storage, Biotransformation of xenobiotics, synthesis of essential vitamins (vitamin K and some of the B complex) and increased absorption of minerals, among others.
In the mucosa and in the intestinal epithelium
- Improving the intestinal barrier function . It is a defense mechanism that helps maintain the integrity of the intestinal epithelium against the action of external aggressions. The manifestation of disorders such as chronic inflammatory bowel disease, celiac disease, enteric infections, some autoimmune diseases, etc., can be the result of the compromise of the integrity of the epithelial barrier, which is why it is very important to influence this point. The ingestion of probiotics contributes to the maintenance of said integrity, as well as to prevent the damages made in the intestinal mucosa by the action of food allergens, pathogenic microorganisms, proinflammatory cytokines, etc., and facilitate their repair; normalize the increased permeability and improve the intestinal inflammatory response. The secretion of mucin, the modulation of protein phosphorylation and the increase in transepithelial resistance are mechanisms directly involved in this function.
- Digestive processes . Involved in the metabolization of lactose (β-galactosidase activity), proteins and lipids, in the synthesis of amino acids and vitamins, fermentation of carbohydrates with the production of short-chain fatty acids and increased absorption of minerals such as calcium, magnesium and iron by a decrease in intestinal pH, an increase in the number of enterocytes and a reduction in phytic acid content.
- Immune system associated with the mucosa . The intestine is the organ with the most important immune function of the organism and where immune responses are controlled against the proteins of the diet (prevention of food allergies) and against pathogenic microorganisms: viruses (rotavirus, poliovirus), bacteria ( Salmonella , Listeria , Clostridium , etc.), parasites ( Toxoplasma ). The intestinal batteries have a great influence on this function and certain probiotics have the ability to alter this intestinal ecosystem, both by stimulating the mucosal immune mechanisms and by stimulating non-immune mechanisms through antagonism and competition with potential pathogens. Specifically, the immunological benefits could be summarized in the activation of local macrophages to increase the presentation of antigens to B lymphocytes and thus increase the production of local and systemic secretory immunoglobulin A, modulate cytokine profiles and induce hyporesponsiveness to the food antigens.
Other organs, such as the brain and the immune system
- Stimulate the immune system acting on cells involved both in the natural and specific immunity and on macrophages.
- They promote the production of immunoglobulins and increase the number of lymphocytes by activating the immune response.
What are they for?
The benefits provided by the intake of probiotics require their regular use and the suitability of the probiotic chosen for the pathological condition to be treated. The beneficial effects demonstrated for the strain studied are not extrapolated to the species or to another strain of the same species; as well as the demonstration of effectiveness of a strain for a specific indication does not make it valid for other different indications either. The studies carried out correlate a specific strain with a certain pathology.
The benefits provided by the intake of probiotics require their regular use and the suitability of the probiotic chosen for the pathological condition to be treated.
The dosage used in the study is also important, since there is no evidence that similar functional benefits are obtained for lower doses, and finally the vehicle or matrix on which the probiotic is administered is also relevant, since it can determine, among other things, the viability of the microorganism.
The main benefits derived from the administration of probiotics are the following:
- They are useful in the prevention and treatment of infectious diarrhea (rotavirus in children) and those due to the consumption of antibiotics: the probiotic microorganism (for example, certain strains of Saccharomyces boulardii , Lactobacillus casei and Lactobacillus rhamnosus ) invades the mucosal surface that has remained deserted, and attenuates the symptoms of the lack of intestinal flora and facilitates recolonization by autochthonous microorganisms.
- Decrease lactose intolerance: Streptococcus thermophilus and L. delbrueckii subsp. bulgaricus contribute to degrade the lactose and thus prevent it from reaching the large intestine without digesting and causing flatulence, abdominal distension, diarrhea, among other symptoms.
- Reduce the symptoms of intestinal inflammation, closely related to damage to the barrier function of the intestinal mucosa. The ability of certain probiotics in their maintenance and restitution (different strains of Streptococcus thermophilus , Lactobacillus and Bifidobacterium ) makes their consumption adequate to help alleviate the symptoms of diseases such as ulcerative colitis or pouchitis .
- Decrease cholesterol levels, by decreasing the plasma concentration of LDL and total cholesterol.
- They modulate the immune system: they reduce the severity of symptoms and prevent some allergic processes, asthma, atopic dermatitis, etc., states that are characterized by a hypersensitivity reaction mediated by immunological mechanisms.
The lines of research with probiotics are currently booming and there are numerous potential therapeutic indications of these products. However, and as already mentioned, studies with proven scientific evidence are required in order to attribute certain therapeutic benefits to a strain.
Useful tips for your administration
It is a fact that the use of probiotics is becoming very important both in the daily diet of many consumers and in clinical practice. The scientific evidences that make known the benefits associated with their consumption cause that they are very well accepted products by the prescriber and by the patient / user.
The dispensing of medicines that include probiotics in their composition will require a medical prescription and / or pharmaceutical advice to improve the understanding by the patient of the effects of the preparation and thus ensure its correct use and adherence to treatment.
Regarding the recommendation to include functional foods that contain probiotics (yogurts and fermented milk, fundamentally) in the daily diet to improve the health of the individual and even to prevent certain diseases, it is important that in parallel it is always advisable to lead a lifestyle healthy, a varied and balanced diet, as well as the practice of regular exercise. So in no way the consumption of probiotics or any other functional food should be understood as the replacement of a healthy and balanced diet or that of a pharmacological treatment prescribed by the doctor.
The consumption of probiotics or any other functional food should not be understood as the replacement of a healthy and balanced diet or as a pharmacological treatment prescribed by the doctor.
The safety profile of this type of product is very high and its administration does not usually cause adverse effects; However, certain population groups (individuals immunosuppressed or in treatments with immunosuppressants, patients with autoimmune diseases, with bloody diarrhea or convalescent cardiac surgery) should avoid its use unless specifically prescribed by the doctor.
A new manual compiles the latest advances in knowledge about probiotics and prebiotics
In order to summarize the latest advances in clinical knowledge in this field, the Spanish Society of Probiotics and Prebiotics (SEPyP) has launched, in collaboration with the pharmaceutical industry, the manual Probiotics, Prebiotics and Health: Scientific Evidence.
The publication, composed of 48 chapters, has been written by more than a hundred expert authors in the field and of recognized prestige. Probiotics, prebiotics and health: scientific evidence has been developed with the purpose of offering a wide range of chapters that gather concepts, data and recommendations in a condensed format, with a large selected bibliography, which will allow those interested to deepen the functions and benefits both probiotics and prebiotics.