Lacticaseibacillus paracasei (Lactobacillus paracasei): A Comprehensive Reference
1. Identity, Nomenclature, and Classification
Current and Historical Names
In 2020, a comprehensive reclassification of the genus Lactobacillus proposed the genus Lacticaseibacillus, which includes the species Lacticaseibacillus paracasei to name the formerly called Lactobacillus paracasei. This reclassification, proposed by Zheng et al. (2020), was based on a polyphasic approach encompassing core genome phylogeny, conserved pairwise average amino acid identity, clade-specific signature genes, physiological criteria, and ecology of the organisms. The species is therefore now formally known as Lacticaseibacillus paracasei, though the historical name Lactobacillus paracasei remains prevalent in older literature and on many commercial product labels.
The high levels of DNA homology among strains belonging to L. casei subspecies led to a reclassification of L. casei subsp. casei (most strains) as Lactobacillus paracasei (Collins et al., 1989). Thus, most genomes designated as L. casei in the NCBI database correspond to L. paracasei. The bacterium comprises diverse Gram-positive bacteria that are very closely related to Lactobacillus casei, belonging to the Lactobacillus casei group. Due to extreme genome similarities between L. casei and L. paracasei, many strains have been cross-placed in the other group.
The species encompasses two recognized subspecies: L. paracasei subsp. paracasei and L. paracasei subsp. tolerans. The current valid name as of the 2020 taxonomic reclassification is Lacticaseibacillus paracasei. Commercially and in research contexts, the species is referred to by a range of strain designations including Lpc-37, F19, and CNCM I-1518, among others — with effects considered to be strain-specific.
Microbiological Characteristics
Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) is a nomadic lactic acid bacterium (LAB) that inhabits a wide variety of ecological niches, from fermented foodstuffs to host-associated microenvironments. Typical cell descriptors include: Gram-positive rods approximately 0.5–0.8 μm × 2.0–4.0 μm; peptidoglycan cell wall with teichoic acids; surface LPXTG-anchored proteins; and variable exopolysaccharide (EPS) production.
Typical genomes range approximately 2.9–3.1 Mb with ~46% GC content. Among 74 sequenced genomes of L. paracasei from GenBank, assembly sizes ranged from 2.3 to 3.3 MB and genome completeness between 88% and 100%. The pan-genome of 75 L. paracasei strains holds 15,945 gene families, while the core genome contained about 8.4% of the total genes.
The long history of use of Lactobacillus species in fermented products has led to their recognition as GRAS (generally recognized as safe) by the US Food and Drug Administration (FDA), and earned them a place on the QPS (qualified presumption of safety) list assembled by the European Food Safety Authority (EFSA).
Natural Sources
Natural sources of L. paracasei include fermented dairy products (yogurt, kefir, cheese), fermented vegetables, and human mucosal isolates (oral and gut). Kefir grains can be considered natural reservoirs of safe and potentially probiotic strains. Studies on kefir grain microbiota have confirmed the presence of Lacticaseibacillus paracasei among other LAB species including Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactiplantibacillus plantarum, and Lactococcus lactis.
The species L. casei, L. rhamnosus, and L. paracasei are "nomadic" and can currently adapt to a wide variety of niches. L. paracasei strains have been found to display similar loss of genes in dairy isolates and high diversity among strains from other sources. The organism has been isolated from a diverse array of environments including traditional African corn-based beverages (mahewu), North African fermented dairy products (lben), Estonian semi-hard cheeses, and human vaginal isolates, indicating its broad ecological flexibility.
Common Dosage Forms and Preparations
Commercial production uses fermentation, harvesting, cryoprotectants and lyoprotectants, and drying processes. In supplement and functional food contexts, L. paracasei is marketed in several forms:
- Dried powders and capsules — the most common pharmaceutical-grade supplement form, containing lyophilized (freeze-dried) or spray-dried live bacteria.
- Fermented dairy foods — yogurts and fermented milk beverages serving as natural delivery matrices.
- Chewable tablets — as used in some pediatric clinical trials (e.g., LP-33 strain at 2 × 10⁹ CFU per chewable tablet).
- Heat-killed (postbiotic) preparations — formulations such as heat-killed MCC1849, where the cells are inactivated prior to delivery, studied for immune effects.
- Synbiotic formulations — combined with prebiotic fibers to support colonization.
2. Traditional and Historical Use
Strains belonging to what is now Lacticaseibacillus paracasei have been part of traditional fermented foods such as yogurt, cheese, and fermented vegetables for centuries. Although L. paracasei itself was not isolated and named until relatively recently (late 20th century), its benefits were unknowingly harnessed through the traditional fermentation of milk and plant-based foods for centuries.
Across Europe, Central Asia, and the Middle East, fermented dairy and vegetable products were staple foods, valued not only for preservation but also for their health-enhancing properties. These foods — such as cultured buttermilk, kefir, and pickled vegetables — often fostered beneficial strains of bacteria including L. paracasei.
In folk medicine, sour milk and fermented drinks were frequently used to calm the stomach, relieve intestinal upset, and rebuild strength during convalescence. They were often prescribed to children and the elderly or used as a restorative after illness.
Historically, such fermented foods were consumed for preservation and flavor; modern use targets specific health endpoints validated in randomized trials at the strain level. A specific example of traditional use linked to verified L. paracasei strains is the North African fermented dairy product lben: Lben is a dairy fermented food that is largely consumed in Tunisia for its numerous health benefits that are related to the existence of probiotics. Similarly, the South African traditional fermented drink mahewu has been identified as a non-conventional isolation source for L. paracasei strains.
L. paracasei comprises diverse strains with a long history of safe use in food and agricultural applications that have been studied for their health-promoting characteristics.
3. Key Constituents, Active Compounds, and Mechanisms of Action
Exopolysaccharides (EPS)
One of the most extensively studied active components of L. paracasei is its capacity to produce exopolysaccharides. One of the main components of Lactobacillus's mechanism of action is EPS. Previous studies have shown that Lactobacillus-derived EPS possesses beneficial anti-inflammatory activities. In addition to the probiotic cells, the EPS produced by LAB has been reported to confer health benefits such as immune modulation, enhanced NK cell activity, antimicrobial activity, and antitumor activity.
EPS from L. paracasei IJH-SONE68 has been shown to significantly decrease accelerated serum IgE levels and the expression of IL-4 mRNA in contact dermatitis model mice. The EPS is thought to interact with pattern recognition receptors on the intestinal epithelium, modulating downstream immune signaling.
Gut Barrier Enhancement
L. paracasei JY062 with its EPS (JEC) alleviated intestinal barrier damage caused by LPS. After JEC intervention on Caco-2 cells, this resulted in upregulation of ZO-1, Claudin-1, Occludin, and MUC2 transcript levels and decreased mRNA expression of Claudin-2. These tight junction proteins are critical to epithelial barrier integrity. Probiotics (especially Lactobacillus species) enhance gut health through various mechanisms, including immune modulation and strengthening of tight junction (TJ) protein expression and localization. These bacteria can also counteract epithelial damage caused by inflammatory mediators or pathogenic toxins by activating innate immune receptors such as Toll-like receptors (TLRs).
Immunomodulation
The mode of action of probiotics is complex and not yet fully elucidated. Many mechanisms have been reported to explain probiotic actions such as antagonism against intestinal pathogens, enhancement of mucosal barrier activity, or modulation of host immune functions.
L. paracasei JY062 with its EPS has been shown to significantly promote M1/M2 type macrophage balance and improve the Treg/Th17 immune axis imbalance. In allergic contexts, allergens promote the proliferation of T helper 2 (Th2) cells, resulting in IL-4 release followed by antigen-specific IgE production. L. paracasei preparations have been shown to shift this Th2-skewed response, partly through augmented Th1 cytokine signaling.
Heat-killed Lacticaseibacillus paracasei MCC1849 effectively induced IL-12 production in mouse spleen cells and significantly reduced cold symptoms in clinical trial subjects. L. paracasei 8700:2 significantly induced the phagocytic capacity of white blood cells in healthy adults and increased the number of natural killer (NK) T lymphocytes within 2 weeks of intake. This was interpreted as a priming of the immune system that could be beneficial, for example in the prevention of viral infections.
Colonization and Persistence
Research has shown that selected L. paracasei L2 strains express high adherence to HCT-116 cells (45.03%), survived under acidic conditions (pH 3), and showed resistance to bile salts. Research has confirmed that L. paracasei's health-promoting properties include its ability to inhibit intestinal pathogens, modulate immune responses, improve lipid metabolism, and exert hypocholesterolemic and stress-reducing effects. One characterized strain, TISTR 2593, exhibited a survival rate of 91.23% after a 3-hour incubation in highly acidic conditions (pH 2.0) and 88.72% after incubation in bile salt solution.
Short-Chain Fatty Acid (SCFA) Production
Some L. paracasei strains have been shown to modulate gut microbial composition in ways that affect SCFA output. Lactobacillus paracasei CNCM I-1572, despite not significantly improving IBS symptoms in one pilot trial, induced a significant reduction in the genus Ruminococcus and a significant increase in the SCFAs acetate and butyrate in IBS patients.
Lactic Acid Production
As a lactic acid bacterium, L. paracasei ferments glucose into lactic acid (also used as the food additive E 270). Lactic acid production contributes to the colonization resistance of the intestine by lowering luminal pH, which is unfavorable for many pathogenic microorganisms.
4. Scientific Evidence by Area of Use
4.1 Gastrointestinal Health — Irritable Bowel Syndrome (IBS)
Several clinical trials have examined L. paracasei in IBS, with mixed outcomes across strains.
In a randomized, double-blind, placebo-controlled study, the efficacy of Lactobacillus paracasei HA-196 and Bifidobacterium longum R0175 in reducing gastrointestinal and psychological symptoms of IBS was evaluated in 251 adults with either constipation (IBS-C), diarrhea (IBS-D), or mixed-pattern (IBS-M). Following a 2-week run-in period, participants were randomized to L. paracasei (n = 84), B. longum (n = 83), or placebo (n = 81). IBS symptoms, stool frequency and consistency, and quality of life were assessed by questionnaires. The differences from baseline in the severity of IBS symptoms at 4 and 8 weeks were similar between groups. This suggests that L. paracasei HA-196 as a single strain was not demonstrably superior to placebo for IBS symptom severity in that trial.
A pilot study assessed the effects of Lactobacillus paracasei CNCM I-1572 on clinical and gut microbiota-related factors in IBS. A multicenter, randomized, double-blind, crossover, 18-week, placebo-controlled pilot trial enrolled 40 IBS patients from five Italian centers. Lactobacillus paracasei CNCM I-1572 did not significantly improve IBS symptoms, including primary efficacy variables of worst abdominal pain/discomfort and IBS degree of relief. Interestingly, however, L. paracasei CNCM I-1572 induced a significant reduction in genus Ruminococcus, a significant increase in the SCFAs acetate and butyrate, and a reduction in immune activation markers.
Among specific strains, Lactobacillus paracasei NCC2461 has shown some efficacy at reducing gastrointestinal symptoms of IBS, such as frequency of bowel movements, pain, and visceral hypersensitivity, in earlier work. A clinical study exploring the effects of Lactobacillus paracasei F19 on IBS symptoms reported an improvement in the bowel habits of participants with constipation or diarrhea.
Evidence assessment: The overall clinical evidence for L. paracasei in IBS is mixed and highly strain-dependent. While some microbiological changes (SCFA elevation, microbiota modulation) are documented in trials, direct improvements in primary IBS symptom scores have not been consistently demonstrated. Larger, well-powered RCTs for individual strains are lacking.
4.2 Allergic Rhinitis
Allergic rhinitis is one of the most studied clinical indications for L. paracasei-based interventions, with a body of evidence centered on the strain LP-33 and related strains.
To test the efficacy of the probiotic Lactobacillus paracasei subsp. paracasei LP-33, a double-blind, placebo-controlled, randomized trial was carried out in patients with allergic rhinitis (AR) to grass pollen treated with loratadine and presenting altered quality of life. Subjects with persistent AR, symptomatic during the grass pollen season, and a positive skin test or specific IgE to grass pollens were included. All received loratadine for 5 weeks. The primary endpoint was the improvement in Rhinitis Quality of Life (RQLQ) global score at the fifth week of LP-33 consumption compared with placebo.
A double-blind, prospective, randomized, placebo-controlled trial examined the efficacy and safety of Lacticaseibacillus paracasei GM-080 in a mouse model of airway hyper-responsiveness and in children with perennial allergic rhinitis (PAR).
A 12-week, double-blind, randomized, placebo-controlled study evaluated the effect of Lactobacillus paracasei (HF.A00232) in children aged 6–13 years with perennial allergic rhinitis.
A systematic review provided significant evidence of beneficial clinical and immunologic effects of L. paracasei LP-33 strains in the treatment of allergic rhinitis. Ingestion of LP-33-fortified fermented milk for 30 days can effectively and safely improve the quality of life of patients with allergic rhinitis, and may serve as an alternative treatment.
Although evidence of a beneficial effect of probiotics on allergic respiratory symptoms is still conflicting, a few studies conducted in children and adults with allergic rhinitis suggested a beneficial effect of the consumption of specific probiotic strains belonging to the Lactobacillus paracasei species.
In one pediatric RCT, the intervention group was provided a daily single dose of a chewable tablet containing 2 × 10⁹ CFU of Lactobacillus paracasei LP-33 for 6 weeks, while the control group received cetirizine.
Evidence assessment: Multiple RCTs, spanning both children and adults, have evaluated L. paracasei strains (especially LP-33 and GM-080) in allergic rhinitis. Results across these trials are generally positive for symptom and quality-of-life measures, though effect sizes are moderate, results vary by strain, and comparisons to antihistamine therapy remain limited. The evidence base is more consistent for allergic rhinitis than for most other indications studied to date.
4.3 Atopic Dermatitis and Skin Health
In reactive skin, oral Lactobacillus paracasei NCC 2461 taken for 2 months decreased skin sensitivity and accelerated barrier-function recovery. Animal and human studies suggest that the anti-allergic mechanism of relevant strains involves modulation of Th2 cytokines and IgE production, consistent with findings in allergic rhinitis models.
In a randomized, double-blind, placebo-controlled clinical trial of L. paracasei IJH-SONE68, sixty subjects were instructed to orally take a capsule containing the IJH-SONE68 powder or placebo every day for 12 weeks. After the clinical trial, scores based on subjects' self-assessment of allergic status were significantly improved in the intervention group compared with the placebo group. This trial included subjects with chronic allergic conditions including skin manifestations.
Evidence assessment: The evidence for skin health benefits (atopic dermatitis, reactive skin) is preliminary. Some strains show promising results in small trials or in composite allergic populations, but dedicated, large-scale RCTs specifically for atopic dermatitis using L. paracasei remain limited.
4.4 Common Cold and Upper Respiratory Tract Infections
Arguably one of the strongest clinical evidence bases for L. paracasei involves reduction in cold frequency and severity, particularly for the strain 8700:2 used in combination with Lactiplantibacillus plantarum HEAL9.
In two earlier studies by Berggren et al. and Busch et al., the combination of L. plantarum HEAL9 and L. paracasei 8700:2 was found to reduce the incidence, severity, and duration of common cold episodes. The same combination was also shown to be of benefit against self-reported cold infections in a population of Swedish children aged 1–6 years attending day care.
A subsequent confirmatory multicenter trial conducted at 14 sites in Germany was undertaken to confirm previously reported results on the efficacy of L. plantarum HEAL9 and L. paracasei 8700:2 against the common cold in healthy adults.
Previous clinical studies showed that heat-killed Lacticaseibacillus paracasei MCC1849 suppresses subjective symptoms among healthy adults, though the mechanism underlying this beneficial effect remained unclear. A randomized, double-blind, placebo-controlled, parallel-group study enrolled 100 healthy adults, divided into MCC1849 or placebo groups. Participants ingested test powder with 5 × 10¹⁰ MCC1849 cells or placebo powder for 4 weeks.
L. paracasei MCC1849 has the potential to improve resistance to common cold infections in susceptible subjects and maintain a desirable mood state, even under mental stress conditions.
Evidence assessment: The combination of L. paracasei 8700:2 with L. plantarum HEAL9 has the best-supported evidence for reduction of common cold incidence in adults, across multiple trials. Heat-killed preparations (MCC1849) also show clinical promise for immune support. However, the confounding factor of multi-strain use and strain specificity limits generalization to L. paracasei alone.
4.5 Gastrointestinal Motility and Bowel Function
Probiotics have received wide attention as a potential way to alleviate gastrointestinal (GI) motility disorders. Research investigated the effects of Lacticaseibacillus paracasei JY062 at 5 × 10⁹ CFU/mL on mice induced by loperamide. After two weeks of probiotic intervention, the probiotic combination alleviated GI motility disorder by increasing the secretion of excitatory GI regulators motilin, gastrin, and 5-hydroxytryptamine (5-HT) and decreasing the secretion of inhibitory GI regulators peptide YY and nitric oxide. This work is preclinical (animal model), and direct translation to human clinical outcomes requires further validation.
4.6 Cardiometabolic Health
Modulating microbial metabolism via probiotic supplementation has been proposed as an attractive strategy for the prevention of cardiometabolic diseases. Lacticaseibacillus paracasei was reported to alleviate metabolic disorders in murine models, however, its beneficial effects in humans remain to be determined. One RCT evaluated whether L. paracasei supplementation could improve endothelial function and cardiometabolic health in subjects with metabolic syndrome (MetS) in a randomized, double-blind, placebo-controlled trial among 130 participants.
Research has explored L. paracasei's health-promoting properties, including its ability to improve lipid metabolism and exert hypocholesterolemic effects. Many foods fermented by LAB possess additional health-promoting benefits such as imparting improvements to digestion and tolerance to lactose, hypocholesterolemic and antihypertensive effects, and antioxidant and anticarcinogenic activities.
Evidence assessment: Preclinical evidence for cardiometabolic effects (lipid metabolism, anti-obesity) is substantial but largely limited to animal models. Human RCT evidence for cardiometabolic outcomes is still emerging, and definitive conclusions await larger-scale human trials.
4.7 Inflammatory Bowel Disease (IBD) — Preclinical Evidence
L. paracasei ST11 (NCC2461) was shown to strongly decrease colitis development in a preventive protocol in an adoptive transfer mouse model. Oral administration of ST11 was safe and had a significant preventive effect on colitis. These results demonstrate that probiotics such as Lactobacillus paracasei harbor worthwhile in vivo immunomodulatory properties to prevent intestinal inflammation by nutritional approaches.
The therapeutic effect of probiotics has been studied in a number of clinical trials for the treatment of IBD, showing that the use of probiotics might be recommended for anti-inflammatory therapy in UC patients. A formulation of live bacteria including L. paracasei may be used in combination with conventional therapies to treat ulcerative colitis.
Evidence assessment: The preclinical evidence for L. paracasei in IBD/colitis is substantial. However, robust, large-scale human RCTs specifically for L. paracasei in IBD are currently lacking. The clinical recommendation to use probiotics in UC is more broadly derived from multi-strain or general probiotic evidence bases.
4.8 Immune Activation and Antiviral Effects
The Lacticaseibacillus paracasei DG strain significantly induced the expression of genes involved in protective antiviral immunity and prevented the expression of proinflammatory genes triggered by SARS-CoV-2 infection. This observation is based on in vitro and preliminary data and has not been confirmed in large prospective human trials.
Oral administration of heat-killed Lactobacillus paracasei MoLac-1 increased the proportion of NK cells in spleen and ameliorated the symptoms of influenza virus (IFV) infection in mice.
Evidence assessment: Antiviral and general immune-stimulating properties are documented in vitro and in animal models, with some human data for cold prevention. Evidence for specific viral disease management remains preliminary.
5. Body Systems and Health Areas of Association
- Gastrointestinal system: Gut microbiota modulation, intestinal barrier reinforcement, short-chain fatty acid production, motility, diarrhea prevention, IBD (preclinical).
- Immune system: Modulation of Th1/Th2 balance, macrophage polarization, NK cell activity, Treg/Th17 axis, dendritic cell activation, IgA production.
- Respiratory/allergic system: Allergic rhinitis (multiple RCTs), upper respiratory tract infection prevention, airway hyper-responsiveness.
- Skin: Atopic dermatitis, reactive/sensitive skin, IgE-mediated hypersensitivity.
- Cardiometabolic system: Lipid metabolism, cholesterol reduction, metabolic syndrome (emerging human evidence).
- Psychological/neurological: Some strains (e.g., MCC1849) have been reported to support mood under stress conditions, though human evidence is limited.
6. Dosage Forms and Doses Reported in Studies
Dosage and preparation in clinical studies are strongly strain-specific. The following figures are drawn directly from peer-reviewed sources:
- L. paracasei LP-33 was administered at 2 × 10⁹ CFU per day (single daily chewable tablet) for 6 weeks in a pediatric allergic rhinitis RCT.
- In a randomized, parallel-group immune study, 100 healthy adults ingested test powder containing 5 × 10¹⁰ heat-killed MCC1849 cells or placebo powder for 4 weeks.
- In a crossover pilot trial, healthy human volunteers consumed capsules containing approximately 24 billion (2.4 × 10¹⁰) live cells of L. paracasei LPC-S01 for 7 days.
- Patent-backed formulations have described dosages of the probiotic ranging from approximately 10⁸ to 10¹¹ CFU, preferably between 10⁸ and 10⁹, or between 10⁹ and 10¹⁰ CFU, depending on the application.
- Clinically tested doses generally range from 1 × 10⁹ to 1 × 10¹¹ CFU/day across diverse trials.
- In the IJH-SONE68 allergy RCT, subjects took capsules containing the IJH-SONE68 strain every day for 12 weeks.
- In a preclinical motility study, L. paracasei JY062 was used at 5 × 10⁹ CFU/mL.
No universally established "standard dose" for L. paracasei supplements exists; effective doses differ by strain, indication, and population studied.
7. Safety Considerations
Regulatory Safety Status
The long history of use of Lactobacillus species in fermented products has led to their recognition as GRAS (generally recognized as safe) by the US FDA and earned them a place on the EFSA QPS list. The qualified presumption of safety (QPS) approach was developed by EFSA to provide a generic pre-evaluation of the safety of biological agents. The QPS approach is based on an assessment of published data for each agent with respect to its taxonomic identity, the body of relevant knowledge, and safety concerns. Safety concerns are, where possible, confirmed at the species/strain or product level and reflected by qualifications.
Antibiotic Resistance
Antibiotic susceptibility is a required safety characteristic for probiotic strains intended for food or supplement use. Antibiotic MIC tests indicated that L. paracasei NTU 101 is only resistant to chloramphenicol. In accordance with EFSA (2012) guidelines, this strain was investigated for the presence of resistance genes; no genes associated with chloramphenicol resistance were detected. Separately, the L. paracasei LPC-S01 isolate was demonstrated to be susceptible to antibiotics indicated by EFSA and does not produce biogenic amines.
Hemolytic Activity
In safety evaluations, L. paracasei TISTR 2593 exhibited non-hemolytic activity (γ-hemolysis) when cultivated on sheep blood agar. The absence of hemolytic activity is a fundamental criterion for selecting probiotic strains, ensuring the nonvirulent nature of the strain, according to FAO/WHO guidelines.
Rare Adverse Events and Immunocompromised Populations
In healthy individuals, L. paracasei has a well-established safety record at typical probiotic doses. However, rare cases of bacteremia associated with L. paracasei have been documented in severely immunocompromised individuals:
Two papers in a recent EFSA QPS review dealt with L. paracasei infections. All of the safety-concern cases described occurred in individuals with severe systemic pathologies leading to immunodepression. Ukai et al. (2025) reported a case of Lacticaseibacillus paracasei bacteraemia in an 8-month-old girl following a jejunostomy for hypoganglionosis who had been taking a probiotic preparation containing L. paracasei. Similarly, a case of L. paracasei infection of a total hip prosthesis has been documented, illustrating that device-associated infections are a theoretical risk in compromised hosts.
In the 2024 EFSA QPS review update, two papers dealt with L. paracasei infections; the identification methodology was not clear in two of these papers, while MALDI-TOF MS was used in the others. The EFSA panel has not recommended removal of L. paracasei from the QPS list on the basis of these sporadic reports.
Strain Specificity
Functional traits such as acid resistance, adhesion, and immunomodulation are strain-dependent and cannot be generalized by species name alone. This principle is recognized across safety and efficacy evaluations: results obtained with one strain do not automatically apply to other strains designated as L. paracasei. The high degree of genome diversity within the species — a pan-genome of 75 strains holds 15,945 gene families — supports the understanding that inter-strain variation in both safety and functional characteristics can be substantial.
Interaction with Antibiotics
Simultaneous administration of broad-spectrum antibiotics is expected to reduce the viability of ingested L. paracasei cells, potentially diminishing any functional probiotic benefit. No clinically significant adverse drug interactions specific to L. paracasei and commonly prescribed medications have been reported in the peer-reviewed literature reviewed here, beyond the general principle that antibiotics may suppress the administered organism. LAB-based probiotics can possess the ability to impart improvements to the intestinal barrier and commensal microbial balance, produce beneficial enzymes and neurochemicals, suppress pathogenic microflora, and modulate the immune system. This immune-modulatory activity is theoretically relevant in the context of immunosuppressive therapy, for which the evidence base is insufficient to draw firm conclusions.
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