Summary of results

• Rebalancing the intestinal microbiota
• Strengthening the intestinal barrier
• Significant reduction in symptoms of irritable bowel syndrome (IBS) : abdominal pain, bloating, diarrhea, digestive emergencies.
• Support of local and systemic immunity
• Reduction of intestinal and systemic inflammation
• Improvement of intestinal transit
• Lower incidence of upper respiratory infections in children
• Indirect effect on general comfort and quality of life
• Improved digestion and absorption
• Restoration of the microbiota after antibiotic therapy

Clinical efficacy of the “Microbiote Boost” formula and its probiotics

Clinical studies on the formula Microbiota Boost

The formula Microbiota Boost combines 8 probiotic strains (Bifidobacterium bifidum, B. infantis, B. longum, Lactobacillus plantarum, L. acidophilus, L. casei, L. rhamnosus and Lactococcus lactis) to support digestive health, gut microbiota and immunity. To date, no published clinical studies have specifically evaluated this combination under the name Microbiota Boost.

Nevertheless, Each of these strains has been the subject of clinical trials or systematic reviews demonstrating benefits in these areas, which justifies their inclusion in the formula. The key points of each strain's effectiveness are summarized below, followed by a comparison table.

✔ Evidence of efficacy by probiotic strain

Bifidobacterium bifidum

Several clinical trials attest to the benefits of B. bifidum on digestive health.
In particular, the strain B. bifidum MIMBb75 significantly relieved symptoms of irritable bowel syndrome (IBS) in a randomized, double-blind trial of 122 patients.
Treated patients reported a significant reduction in abdominal pain, bloating, digestive urgency and better digestive comfort compared to placebo, as well as an improvement in their quality of life. In addition, B. bifidum helps strengthen the intestinal barrier: studies indicate that it reduces intestinal permeability by increasing the expression of tight junction proteins, thus protecting the digestive mucosa from inflammation.
This barrier effect may partly explain its clinical efficacy. Finally, B. bifidum appears to favorably modulate the local immune response – for example by decreasing the production of pro-inflammatory cytokines in the intestine – which accompanies the improvement of digestive symptoms observed in IBS patients.

Bifidobacterium infantis

The strain B. infantis 35624 is well documented for digestive and immune support. Randomized clinical trials have shown that it significantly alleviates abdominal pain, bloating and other IBS symptoms compared to placebo. For example, in patients with IBS, the administration of B.infantis resulted in improved symptom scores and a normalization of the cytokinar profile : the abnormal IL-10/IL-12 ratio (indicator of the anti/pro-inflammatory balance) in these patients returned to normal under B. infantis.
This suggests a significant immunomodulatory effect, reducing intestinal inflammation. In terms of the microbiota, B. infantis helps rebalance the intestinal flora, particularly in people whose microbiota is disturbed. Its implantation promotes the production of beneficial organic acids and the inhibition of pathogens, thus strengthening the intestinal ecosystem.
Overall, the systematic reviews confirm the potential of B. infantis (especially when incorporated into multi-strain formulas) to improve IBS symptoms without significant adverse effects.

Bifidobacterium longum

B. longum is considered a key species of the intestinal microbiota, with multiple demonstrated benefits.
On the digestive level, certain strains have shown positive effects in IBS and inflammatory bowel diseases.
For example, one clinical study reported that an 8-week treatment with B. longum 35624 resulted in a significant symptom relief in adults with IBS, compared to placebo.
B. longum also contributes to the intestinal barrier protection : It has been observed to decrease intestinal permeability by stimulating the production of metabolites such as propionate, which strengthens tight junctions between cells and reduces local inflammation. In addition, B. longum can favorably modulate the composition of the microbiota.
For example, the association of B. longum BB536 with L. rhamnosus HN001 in humans significantly reduced the proportion of opportunistic bacteria while increasing beneficial bacteria in the gut. Finally, B. longum has important immune properties: the strain B. longum BB536, tested in elderly people, significantly reduced the incidence of flu and fever compared to placebo, thanks to a stimulation of innate immunity (increased activity of NK cells and neutrophils). This ability to strengthen the body's defenses positions B. longum as an ally for immunity, in addition to its digestive effects.

Lactobacillus plantarum

Several strains of L. plantarum have proven their effectiveness in soothing functional digestive disorders.
For example, the administration of L. plantarum 299V for 4 weeks provided notable relief to IBS patients, with reduction of abdominal pain and bloating in a large majority of patients (95% improvement with probiotic vs. 15% with placebo).
Likewise, the strain L.plantarum CCFM8610 has been shown to be effective in a controlled clinical trial in patients with diarrhea-predominant IBS: it has reduced diarrhea and improved quality of life, while correcting the associated intestinal dysbiosis. In terms of the microbiota, L. plantarum in fact helps to rebalance the flora and to strengthen the integrity of the mucosa.
Research, including in animals, shows that L. plantarum can increase the expression of tight junction proteins (occludin, ZO-1), thereby improving the barrier function of the intestine. At the same time, L. plantarum exercises a local anti-inflammatory effect : in an IBS model, strain CCFM8610 significantly reduced the expression of pro-inflammatory cytokines (such as IL-1β, IL-6) and other mediators of visceral hypersensitivity, while increasing the production of beneficial metabolites (e.g., conjugated linoleic acid) related to these effects.
In short, L. plantarum acts in synergy on several fronts – microbiota, barrier and immunity – to soothe digestive disorders.

Lactobacillus acidophilus

Often used for a long time in fermented products, L. acidophilus is well documented for its beneficial effects on transit and immunity.
Clinical studies and reviews have shown that L. acidophilus reduces the duration and severity of acute diarrhea, especially in children.
Through its action, episodes of gastroenteritis (for example rotavirus) are shortened and stools return to normal more quickly than with the placebo.
In parallel, L. acidophilus contributes to maintain homeostasis of the intestinal microbiota. It produces lactic acid and bacteriocins that inhibit pathogens (E. coli, Clostridium, etc.), promoting a healthy microbial environment. This strain has been shown to help preserve the integrity of the intestinal epithelium and prevent excessive colonization by unwanted germs, resulting in an overall improvement in functional gastrointestinal disorders.
Finally, L. acidophilus strengthens the immune system. It stimulates both innate and adaptive immunity: for example, its consumption is associated with an increase in IgA production and a better response to digestive infections. Studies have also noted an increase in anti-inflammatory cytokines and a favorable modulation of the immune response (reduction of an excessive response to food antigens, improvement in certain allergies) under L. acidophilusThese multiple actions make L. acidophilus a versatile probiotic for gut health and immunity.

Lactobacillus casei

L. casei is known for its ability to survive in the digestive tract and exert notable probiotic effects there.
From a digestive point of view, it has demonstrated effectiveness in the prevention of antibiotic-associated diarrhea (AAD).
For example, a controlled trial in hospitalized patients showed that daily consumption of L. casei Shirota (≥6.5×10^9 CFU) during antibiotic therapy reduced the incidence of AAD to 17% versus 55% in the control group without probiotic (p<0.001).
This significant reduction in the risk of diarrhea under antibiotics is accompanied by a reduction in infections Clostridioides difficile in some studies, making L. casei an interesting adjuvant in the prevention of complications of antibiotic therapy. L. casei also acts on the intestinal microbiota : its strains can modulate the composition of the flora by stimulating the growth of beneficial bacteria and slowing that of pathogens. Thus, experiments show that L. casei favorably alters the colon microbiota and promotes a healthy microbial balance.
On the immune level, L. casei is particularly interesting for its effect on mucosal immunity. Studies (in animals as well as in vitro) indicate that it activates innate defenses via the TLR/NF-κB pathway, leading to the activation of macrophages and dendritic cells. It thus stimulates the production of cytokines that direct the immune response.
Furthermore, the consumption of L. casei has been associated with increased NK cell activity and modulation of the balance Th1/Th2 in favor of a better antiviral response while avoiding excess inflammation. These immunomodulatory effects translate concretely into better resistance to infections: for example, the contribution of L. casei Shirota has been correlated with a lower incidence of winter respiratory infections in certain risk groups.
In summary, L. casei contributes to digestive health (particularly in the prevention of diarrhea) while strengthening the microbiota and intestinal immune defenses.

Lactobacillus rhamnosus

The strain L. rhamnosus GG (LGG) is one of the most studied probiotics in the world, with a wide range of demonstrated benefits.
On the digestive level, LGG is effective in treating and preventing acute diarrhea, especially in children. The most recent meta-analyses confirm that the administration of L. rhamnosus GG significantly shortens the duration of diarrhea of approximately 0.5 to 1 day on average compared to no probiotic.
This effect, observed in at least 15 randomized trials involving more than 3000 children, is more marked when high doses (≥10^10 CFU/day) are used early in gastroenteritis.
In prevention, LGG has also been shown to be useful in reducing the incidence of pediatric nosocomial diarrhea and AAD, as noted by several hospital studies.Regarding the intestinal microbiota, L. rhamnosus contributes to restore a healthy balance of the flora, particularly after disturbances (antibiotics, infections). It produces antimicrobial substances and promotes the growth of beneficial commensal bacteria, thus helping to prevent dysbiosis.
In addition, LGG strengthens the intestinal barrier : it has been shown to stimulate the regeneration of the intestinal epithelium. Indeed, LGG secretes a protein (p40) capable of activating EGF receptors on epithelial cells, which promotes the survival and growth of enterocytes while reducing their apoptosis, thus contributing to the integrity of the mucosa.
Finally, L. rhamnosus has major effects on theimmunitySchool trials have shown that taking LGG daily reduces the incidence and duration of upper respiratory infections in children.
For example, in a study of 281 daycare children, the group receiving LGG showed 34% fewer ear infections and colds than the placebo group over 3 months (RR = 0.66) and significantly fewer days with respiratory symptoms. An increase in salivary IgA levels and a better influenza vaccine response were also observed in subjects consuming L. rhamnosus. LGG is therefore a key probiotic which balances the microbiota, strengthens the intestinal barrier and boosts immune defenses, which explains its effectiveness in reducing both digestive disorders and infections.

Lactococcus lactis

Although it is less famous than lactobacilli and bifidobacteria, L. lactis is a probiotic bacteria of growing interest, with emerging studies on its benefits.
On the digestive level, L. lactis is recognized for improve digestion and nutrient absorption. For example, preclinical work has shown that adding L. lactis increases the activity of digestive enzymes (proteases, etc.), which results in better food breakdown and improved growth in the tested models.
These results suggest that it could help relieve certain digestive disorders linked to incomplete digestion or enzyme deficiencies.
Moreover, L. lactis contributes to balance the intestinal microbiota by producing natural antimicrobial substances (lactic acid, bacteriocins) which inhibit pathogenic bacteria and unwanted yeasts. This action cleans the intestinal ecosystem and prevents dysbiosis. L. lactis is also traditionally used in fermented products not only for its technological qualities, but also because it limits the proliferation of harmful germs during fermentation (for example, L. lactis subspecies cremoris in certain milk preparations). On the immune side, L.lactis turns out able to stimulate the immunity of the intestinal mucosa. A study on an animal model has shown that the strain L. lactis PH3-05 induces an increase in gene expression muc-2 (involved in the production of protective mucin) and the gene IL-10 (anti-inflammatory cytokine) in the intestine. This suggests a strengthening of the mucosal barrier and a local anti-inflammatory effect.
Moreover, L. lactis has shown his ability to modulate immune responses : through its metabolites, it can promote a balanced, tolerogenic response, thus reducing excessive inflammation while maintaining immune vigilance against pathogens.
In summary, although human clinical studies on L. lactis are still limited, the available data indicate that it has a positive effect on digestion, intestinal flora and immunity, which justifies its presence in the formula Microbiota Boost in addition to other strains.

Key scientific references

 Guglielmetti et al. (2011) – B. bifidum MIMBb75 in RCT SII: significant improvement in symptoms and quality of life pubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov.

 O'Mahony et al. 2005) – B. infantis 35624 in IBS: reduction of symptoms associated with normalization of the IL-10/IL-12 ratio (anti-inflammatory profile)pubmed.ncbi.nlm.nih.govgastrojournal.org.

 Namba et al.(2010) – B. longum BB536 in seniors: 68% drop in incidence
influenza and increased innate immune activity (NK, neutrophils) pubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov.

 Niedzielin et al. (2001) – L. plantarum 299V double-blind IBS: 95% of patients improved vs. 15% placebo (pain and transit normalized) pubmed.ncbi.nlm.nih.gov.

 Chen et al. (2021) – L. plantarum CCFM8610: anti-inflammatory effects (IL-1β, IL-6 and anti-dysbiosis in an IBS model pubs.rsc.org.

 Nawazish et al. (2023) – Review L. acidophilus : reduction of childhood diarrhea and
immune modulation (↑ IgA, epithelial integrity) mdpi.commdpi.com.

 Muthu et al. (2014, BMJ) – L. casei in DAA prevention: risk of post-antibiotic diarrhea greatly reduced with L.casei Shirota cambridge.org.

 Szajewska et al. (2019) – Meta-analysis L. rhamnosus GG: acute pediatric diarrhea
shortened (~0.85 days on average) pubmed.ncbi.nlm.nih.gov.

 Hojsak et al. (2010) – L. rhamnosus GG in daycare: significant reduction in upper respiratory infections in children (34% lower risk) pubmed.ncbi.nlm.nih.gov.

 Sun et al. (2024) – L. lactis PH3-05 (preclinical study): ↑ enzymatic activity
digestive, ↑ expression of muc-2 And IL-10 (better barrier and anti-inflammatory response) mdpi.commdpi.com.