Prebiotics and probiotics are two key categories of substances that play a very important role in maintaining the delicate balance of our gut, promoting gastrointestinal health, and contributing to the overall well-being of the body.
These compounds, often associated with terms such as "fermentable fiber" and "good bacteria," are the subject of increasing scientific interest and are gaining popularity as key elements for a balanced diet.
In this article, we will explore what prebiotics and probiotics are exactly, how they influence our health, and how we can integrate them into our daily diet to improve our well-being.
What are probiotics
Probiotics are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host".
These microorganisms, mainly bacteria but also including yeasts, are naturally present in fermented foods, can be added to other food products, and are available as dietary supplements.
Probiotics are identified by their specific strain, which includes the genus, species, subspecies (if applicable), and an alphanumeric strain designation.
The seven main genera of microbial organisms most often used in probiotic products are Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, Escherichia and Bacillus.
Certified composition of Pro-Bio24 — 6 strains selected for taxonomic complementarity:
| Strain | Classification | Certified code | CFU per capsule |
|---|---|---|---|
| Saccharomyces boulardii | Probiotic yeast | SGSb01 | 8 billion |
| Limosilactobacillus reuteri | Lactobacillus | Lr92 | 2 billion |
| Bifidobacterium longum | Bifidobacterium | DSM 16603 | 4 billion |
| Lactobacillus acidophilus | Lactobacillus | UALa-01 | 4 billion |
| Lacticaseibacillus rhamnosus | Lactobacillus | Lr-32 | 4 billion |
| Lactiplantibacillus plantarum | Lactobacillus | Lp-115 | 2 billion |
| Total CFU per capsule | 24 billion | ||
What foods contain prebiotics
Common sources of probiotics include yogurt, cultured buttermilk, and cheese.
Other foods obtained through bacterial fermentation include Japanese miso, tempeh, sauerkraut, beer, sourdough, bread, chocolate, kimchi, olives, and pickles.
Another fermented dairy product is kefir.
However, among these, yogurts and fermented milks remain the main food vehicles for probiotics, offering a relatively low pH environment essential for the survival of probiotic bacteria.
Probiotic strains are also found in non-dairy fermented substrates, including soy products, cereals, legumes, cabbage, corn, pearl millet, sorghum, and so on.
Dairy products represent the most common and preferred food category by consumers, rich in lactic ferments.
However, dairy products are associated with an increased risk for people with lactose intolerance, galactosemia, milk protein allergy, and high cholesterol levels.
For this reason, the market increasingly demands the use of probiotic lactic ferment supplements as a valid alternative.
What are lactic ferments?
"Lactic ferments" and "probiotics" are often confused with each other, even by healthcare professionals.
Lactic ferments or lactic acid bacteria are bacteria capable of producing lactic acid from the fermentation of lactose.
The term therefore refers to a microbial function that microorganisms, even diverse ones, are capable of performing.
The term "lactic ferment" is more famous than "probiotic"; the reason is probably historical, as the use of lactic ferments in antiquity served to preserve milk.
The difference is clear: on the one hand, lactic ferments, of which we cannot be sure of any effects; on the other hand, probiotics, stored in databases, of which we know exactly the species, strain, and molecular detail, with the safety, technological, functional, and physiological criteria required by the WHO.
These criteria are necessary for a given product to be called a probiotic and to be sold as such.
What are probiotics used for
Probiotics are important for improving digestion and nutrient absorption in our body, because they help break down foreign substances (such as medicines or pollutants) reducing the risk of side effects and are essential for intestinal health.
The microbiota, composed of beneficial bacteria, helps produce important substances such as fatty acids, vitamins and amino acids, contributing to nutritional needs.
Probiotics keep the gut healthy, competing with harmful bacteria in the intestine, preserving its structural integrity and barrier function.
The gut microbiota also plays a key role in supporting a healthy immune system and interacts with different parts of the body through complex biochemical signals.
This interaction is known as the microbiota-gut-brain axis and microbiota-gut-lung axis.
Gut bacteria can influence not only the gut but also anatomical districts such as the brain and lungs.
Changes in the microbiome, caused by chronic stress, drugs or contaminated food, could alter immune function and the balance in the central nervous and respiratory system.
Probiotics and the immune system: the latest evidence
Scientific research in 2026 has further deepened our understanding of the role of probiotics in modulating the gut microbiota. A review published in Current Pharmaceutical Biotechnology (Sarogi et al., 2026) analyzed the mechanisms through which different probiotic strains interact with the intestinal barrier and immune system cells.
The study highlights an important point: these effects are strongly strain-specific. Not all microorganisms act in the same way, and CFU count alone is not enough to guarantee the effectiveness of a formulation. The research indicates that documented compatibility between the strains present in a formula, together with their certified identification in international scientific collections, are fundamental parameters when choosing a quality probiotic.
Research on this topic is constantly evolving. Effects depend on the specific strain and the dose taken.
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What is the difference between probiotics and prebiotics
Prebiotics are not to be confused with probiotics, as they are non-digestible food compounds that selectively promote the growth and activity of beneficial bacteria in the colon.
In other words, they are substances that provide the necessary nourishment for beneficial gut bacteria.
So, probiotics are living microorganisms, prebiotics are substances that promote the growth and activity of beneficial bacteria already present in the intestine.
Often, it is advantageous to consume both in the diet to support a balanced intestinal bacterial flora and promote the body's health.
When to take probiotics?
The question of the optimal time to take a probiotic supplement remains debated, as numerous factors influence the product's effectiveness.
To date, there is insufficient data to define with reasonable certainty the best time for intake.
Most manufacturers rely on a specific study published in 2011 which, through counting, evaluated the impact of administration time relative to meals and the influence of food's buffering capacity on probiotic survival during gastrointestinal transit.
Counting performed during and after transit through gastric and duodenal models showed that the survival of all bacteria present in the product was better when administered during a meal or 30 minutes before a meal (it should be noted that the meal consisted of oatmeal cooked with milk, a meal uncommon in our latitudes).
Probiotics administered 30 minutes after this meal showed lower survival.
The presence of fats seems to have some positive impact, as survival in 1% fat milk and oatmeal porridge was significantly better than in apple juice or spring water.
The Saccharomyces cerevisiae boulardii strain was not affected by mealtime or meal buffering capacity.
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The best lactic ferments
If you are considering purchasing a probiotic lactic ferment supplement, it is essential to keep in mind that, while they may seem similar, there are often notable differences that affect their effectiveness.
Evaluate these five useful parameters before deciding which product to choose.
- Number of bacterial species with specific count, a supplement containing more different species derived from international collections is considered more effective
- Number of live bacteria (CFU) per capsule, effectiveness is dose-dependent
- Absence of allergens, such as Lactose and Gluten makes it suitable for people with allergies or intolerances
- Absence of additives such as artificial sweeteners or colorants, some additives can affect the stability of the bacteria themselves as well as cause adverse reactions.
- Number of live bacteria (CFU) relative to price
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Particularly relevant, especially in relation to point 5, which considers the number of live bacteria (CFU) in relation to price, is the incredible difference found between one brand and another.
According to our market analysis, the best-selling probiotic lactic ferment supplements in Switzerland have an average cost per billion bacteria that is almost 100 times higher than that of PRO-BIO24.
Are probiotics safe?
Probiotics are generally recognized as safe by the US Food and Drug Administration (FDA) or are subject to qualified presumption of safety (QPS) by the European Food Safety Authority (EFSA).
However, while probiotics are available to healthy consumers as dietary supplements or foods, certain patient populations use them.
It is important to remember that long-term studies aimed at demonstrating the safety of probiotics in at-risk populations, such as individuals with weakened or compromised immune function, elderly individuals, and infants (especially premature infants), are still limited.
Currently, caution is suggested in the use of probiotics in vulnerable populations.
In particular, in the presence of a single major risk factor, such as an immunocompromised state, or more than one minor risk factor, special attention should be paid to the use of probiotics.
Research continues on this topic to gain a deeper understanding of the safety of probiotics, especially in specific clinical contexts.
Frequently asked questions about probiotics and prebiotics
Q: What is the difference between probiotics and lactic ferments?
A: Lactic ferments are bacteria that produce lactic acid from the fermentation of lactose — a historical term linked to milk preservation. Probiotics, on the other hand, are living microorganisms identified at species and strain level, stored in international databases, with safety criteria defined by the WHO. Not all lactic ferments are probiotics, but all bacterial probiotics belong to the lactic ferment category.
Q: How many billion bacteria should a good probiotic contain?
A: The CFU (colony-forming units) count is an important parameter, but not the only one to consider. The taxonomic diversity of the strains present and their certified identification in international scientific collections are equally important. A probiotic with compatible, certified strains offers more guarantees than one that only competes on the number of billions stated on the label.
Q: Can probiotics be taken during antibiotic therapy?
A: Yes, with one precaution: it's recommended to space out the intake of the probiotic and the antibiotic by at least 2 hours. Some strains, such as Saccharomyces boulardii, being a yeast rather than a bacterium, are not affected by bacteriostatic antibiotics. In any case, it is always advisable to consult your doctor or pharmacist.
Q: Are probiotics safe?
A: The main probiotic strains are recognized as safe by the US FDA and are subject to the qualified presumption of safety (QPS) by the European EFSA.
Caution is nevertheless recommended for vulnerable populations such as immunocompromised individuals, frail elderly people, and premature infants, who should consult their doctor before taking probiotics.
Q: Is it better to take probiotics on a full or empty stomach?
A: The question of the optimal time to take probiotics remains debated. To date, there are no human studies that directly compare time windows (before/during/after meals) in terms of fecal survival or clinical outcomes. However, in vivo studies show that most bacterial strains survive better when taken 30 minutes before a meal, during the meal, or immediately after — in all cases not on an empty stomach and not more than 30 minutes after the meal. The fat content of the meal was likely more decisive than the protein content. Saccharomyces boulardii was not affected by timing.
Q: What does it mean for a probiotic strain to be "certified"?
A: A certified strain is identified at the molecular level using techniques such as genetic fingerprinting and is deposited in an internationally recognized microbiological collection, such as the German DSMZ. The alphanumeric code accompanying each strain — for example, DSM 16603 for Bifidobacterium longum — is the official deposit number that guarantees traceability from origin to capsule.
Q: What is the difference between a single-strain and a multi-strain probiotic?
A: A single-strain probiotic contains only one type of microorganism, while a multi-strain probiotic contains several. Scientific research studies how the taxonomic diversity of strains — that is, the presence of different genera and species — can influence the composition of the gut microbiota more broadly than single-strain formulations. It's important that the strains in a multi-strain formulation are selected for compatibility and absence of mutual competition.
Sources:
- Cells. 2023 Jan; 12(1): 184. doi: 10.3390/cells12010184, Probiotics Mechanism of Action on Immune Cells and Beneficial Effects on Human Health
- Gut Microbes. 2023; 15(1): 2185034. doi: 10.1080/19490976.2023.2185034, Emerging issues in probiotic safety: 2023 perspectives; Nutrients doi: 10.3390/nu14235155, Microbiome Therapeutics for Food Allergy
- Sarogi GK et al. (2026) – Immunomodulatory Roles of Probiotics: From Intestinal Barrier Regulation to Clinical Applications. Current Pharmaceutical Biotechnology. doi: 10.2174/0113892010455159260407152252
- De Biasi J et al. (2026) – Biotics: The Food Ingredients Supporting the Intestinal Microbiota and Immune System. Nutrition Reviews. doi: 10.1093/nutrit/nuaf252
- Horvath A et al. (2026) – The beneficial effect of a multispecies probiotic intervention on quality of sleep: a randomized, double-blinded, placebo-controlled study. Journal of Psychiatric Research. doi: 10.1016/j.jpsychires.2026.01.040
- Mingat SX et al. (2026) – Synbiotic effects of 2'-fucosyllactose and Bifidobacterium longum subsp. infantis M-63. Frontiers in Nutrition. doi: 10.3389/fnut.2026.1744839
