Taking probiotics has multiple positive effects on the gut and its microbiota

Probiotics are living microorganisms that, when taken in adequate amounts, offer a health benefit to the host.¹ Probiotics that are most commonly used can be either bacterial or yeast microbes.¹

Why are probiotics beneficial?

The benefit of probiotics in gut functioning is related to their influence on the gut microbiota.¹

Microbiota are trillions of microorganisms that live in a mutually beneficial  relationship with the gut.¹  These microorganisms are found mainly in the colon, and offer many benefits including stimulation of immune function and fermentation of substrates that contribute to the host cell nutrition.²

The gut microbiota is introduced from birth, mainly from the mother and also from the environment.² The microbiota that is present after birth changes during the first three years of life and reaches a “stable” population in the adult years.³ However, during those first years, the microbiota population that is established is influenced by factors including gestational age, mode of birth delivery, breastmilk vs bottle-fed, exposure to antibiotics or short-term illnesses.² Disturbances to diversity of microbiota in those early years can lead to allergies and obesity later in life.³

In adults, the gut microbiota diversity and composition can be affected by many factors including diet, exposure to medications (e.g. antibiotics), illness and age.³ The results can include diarrhea, inflammatory conditions and overgrowth of harmful bacteria.⁴

Probiotics work by positively affecting the ecosystem of the gut.¹  They do this by either creating an environment that favours the growth and re-establishment of normal gut microbiota, improving gut physiology (including increasing the mucus barrier which prevents harmful bacteria from accessing cells), digest food, or influencing the immune system (including increasing the secretion of antibodies that can target harmful bacteria).^1,3

Probiotics exist in different forms³, such as fermented foods, supplements, and probiotic drugs³ (Table 1).

A probiotic should not be confused with a prebiotic, which is a fermentable ingredient (usually non-digestible carbohydrates) that is a food source for microbiota and probiotics.¹ For example, breast milk and sugars found in certain fruits such as bananas are prebiotics.¹ Nor should it be confused with postbiotics, products or metabolites produced by bacteria that also offer health benefits, but are not living organisms.⁷

The classification of a probiotic as a drug, food or food supplement also reflects the level of clinical evidence regarding efficacy and safety.³ A probiotic food or food supplement does not exert therapeutic action, but may have health benefits.³ A probiotic food is consumed in a balanced diet while a probiotic food supplement is aimed to supplement a normal diet.³

A probiotic label may not describe all the strains it contains.⁹ This is very important as some probiotics offer different health benefits compared to others, and not all strains have the same level of clinical evidence that demonstrates their health benefit.^3,8

Also, probiotics can be manufactured differently, require different storage conditions and contain different numbers of strains.¹ Some probiotics can be affected by antibiotics¹⁰, while some may not survive the harsh conditions of the stomach³ and therefore there are less reaching the gut.¹ For example, a bacterial species commonly found in fermented dairy products (Lactococcus lactis) has high sensitivity to acid and bile and only lasts for a short time in the gut.¹¹

Why is Saccharomyces boulardii CNCM I-745 a good choice of probiotic?

Saccharomyces boulardii CNCM I-745 is a unique single-strain yeast probiotic. It is the first discovered probiotic drug and offers multiple gastrointestinal benefits.³ S. boulardii CNCM I-745 has many advantages that make it suitable as a probiotic, such as:

• Naturally non-susceptible to antibiotics so it can be taken at the same time as antibiotics¹⁰ ;
• Can tolerate acidic nature of stomach which means that it can survive and pass through to the intestine⁴ ;
• Grows at human body temperature (37°C) unlike other yeast probiotics⁴ ;
• Does not permanently colonize the gut, which means that the normal balance of microbiota is not disturbed by its presence.⁴

Due to its long history, S. boulardii CNCM I-745 has strong clinical evidence demonstrating its efficacy including :

• Stimulating immune responses to prevent colonization by harmful bacteria that can lead to a disruption of the normal gut microbiota diversity.⁴
• Acting on harmful bacterial species such as Clostridium difficile to prevent overgrowth or prevent the activity of toxins³ ;
• Treating acute diarrhea associated with infection¹ ;
• Restoring the normal microbiota diversity following a disruption such as antibiotic treatment⁴ ;

Because of the strong clinical evidence,