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Information for healthcare professionals


A probiotic dossier of evidence should include studies that give some insight into the mechanisms of activity behind any observed benefit, studies that demonstrate the strain's survival through the gut and positive effects on the colonic bacteria, and studies that demonstrate safety.

Scroll down to read key examples below for Lactobacillus casei Shirota, showing:

Survival through the gut

Survival through the gut is considered a key characteristic of probiotic strains as the mechanism of activity underlying most health benefits is associated with the transient presence, growth and activity of the live probiotic cells in the colon. A simple way to demonstrate this scientifically is to check for the presence of the live strain in the faeces of volunteers who have ingested the probiotic. This has been done in several trials with Yakult (contact us for reference list).

Tuohy KM et al (2007)

Survivability of a probiotic Lactobacillus casei in the gastrointestinal tract of healthy human volunteers and its impact on the faecal microflora. J Appl Microbiol 102 (4):1026-1032.

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This study was conducted by scientists at the University of Reading, and involved 20 healthy volunteers who for 21 days consumed either L. casei Shirota (Log 10 8.6 ±0.1 cells as Yakult) or a placebo drink not containing the probiotic. After this, live cells of L. casei Shirota in their faeces were cultured and counted using selective nutrient agar, and colony identify was confirmed by pulsed field gel electrophoresis.

Seven days after the subjects started to ingest the probiotic, L. casei Shirota was recovered at a mean level of Log10 7.1 ±0.4 CFU per gram of faeces. Numbers stayed at this level whilst the probiotic was being consumed. Seven days after the volunteers stopped ingesting the probiotic, the strain was still detected in the faeces of six of them although at a lower level (Log10 5.0 ±0.9 CFU per gram of faeces).

Increase in beneficial bacteria

Lactobacilli and bifidobacteria are genera that are widely considered to be beneficial in the gut:

  • They can produce beneficial metabolites: e.g. short chain fatty acids; vitamins
  • Their growth promotes acidic conditions in the colon, inhibiting harmful bacteria
  • Reduced levels of bifidobacteria and/or lactobacilli are associated with certain disease states (e.g. functional gut disorders, allergy, antibiotic-associated diarrhoea)
  • Positive health benefits have been observed when numbers of bifidobacteria and lactobacilli in the gut are restored or maintained

Lactobacillus: Gram-positive facultative anaerobic rods found widely in nature and often used to make fermented foods such as cheese, yoghurt, pickles, salami etc. Lactobacilli are classed as either homofermentative (when lactic acid is the main metabolic product) or heterofermentative (when ethanol and carbon dioxide are also produced). Lactobacilli form part of the normal commensal intestinal microbiota, detected in adults at a level of about Log10 6.0 – 8.0 per gram of faeces (wet weight).

Bifidobacterium: Gram-positive anaerobes, often with a branched (bifurcated) appearance. They produce lactic acid but are not usually termed as lactic acid bacteria due to phylogenetic and metabolic differences. Bifidobacteria are early colonisers of the gut; breast feeding promotes this. In adults they are major constituents of the colonic microbiota, detected at levels of about Log10 8.0 – 10.0 per gram of faeces (wet weight).

Spanhaak et al (2007)

The effect of consumption of milk fermented by Lactobacillus casei strain Shirota on the intestinal immune parameters in humans. Eur J Clin Nutr 52: 899-907.

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This double-blind, placebo-controlled, randomised trial in the Netherlands involved 20 healthy adult men who consumed either 3 x 100ml a day of probiotic drink (containing 109 CFU L. casei Shirota/ml) or the same quantity of an unfermented milk drink placebo. Probiotic consumption was associated with changes to the composition of intestinal microbiota: increased Lactobacillus counts with significant increase in L. casei Shirota (P less than 0.01); significant increase in Bifidobacterium (P less than 0.05) and a trend for reduced numbers of other species such as Clostridium.

By the second week of the intervention period there was also a significant reduction in the activity of two enzymes associated with carcinogen formation (both P less than 0.05) and at the end of the intervention period there was a significant increase in moisture content of faeces (P less than 0.05).

Decrease in harmful bacteria

The intestinal microbiota comprises a range of bacteria: some beneficial, some neutral for health, some pathogenic or harmful. In the latter case, this may be due to production of toxins, carcinogens or other harmful substances that in the long term may have a negative health outcome.

Different studies with L. casei Shirota have reported, for example, that its consumption has been associated with reduction of Clostridium difficile (see below), Helicobacter pylori (see below) and numbers of certain Enterobacteriaceae.

Decrease in harmful substances: improved gut milieu

There is no consensus of 'an ideal intestinal microbiota', but it is generally considered better for health for the microbiota to be predominantly saccharolytic, producing short chain fatty acids such as butyrate, acetate, propionate, etc. These metabolites help increase gut motility, decrease pH, provide energy for the commensal bacteria and absorb minerals. Butyrate is particularly important for regulation of the colonic epithelial cells' growth and differentiation, reducing inflammation and carcinogenesis.

Proteolytic fermentation produces potentially toxic and carcinogenic compounds including ammonia, phenols, indoles and amines.

De Preter V et al (2004)

The in vivo use of the stable isotope-labelled biomarkers lactose- [15N]ureide and [2H4]tyrosine to assess the effects of pro-and prebiotics on the intestinal flora of healthy human volunteers. Br J Nutr 92:439-446.

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Researchers at the University Hospital Leuven in Belgium investigated the effects of Lactobacillus casei Shirota (LcS) on toxic fermentation metabolites in a randomised, single-blinded, placebo-controlled, crossover study of healthy subjects (n=19) consuming either the probiotic (containing 6.5 x109 LcS), a prebiotic or the respective placebo twice a day for two weeks, with an intervening two week washout period.

The effects of these interventions were assessed by giving the volunteers a test meal with labelled biomarkers and then analysing their urine for phenolic compounds, total nitrogen content and 15N. The results indicated a reduction in production of the toxic fermentation metabolites NH3 and p-cresol for the probiotic group (P = 0.032 and P = 0.047 respectively), which was significantly different to the placebo group (P = 0.042 and P = 0.016 respectively).

Other studies have confirmed association of L. casei Shirota consumption with significant decrease of urinary p-cresol excretion (De Preter et al 2007). A model study also showed that L. casei Shirota reduced intestinal absorption of bisphenol A (Oishi et al 2008) and an in vitro study showed binding of aflatoxin by this strain (Hernandez-Mendoza et al 2009).

Available Papers

Shida et al (2011) Flexible cytokine production by macrophages and T cells in response to probiotic bacteria

Pirker et al (2013) Effects of antibiotic therapy on the gastrointestinal microbiota and the influence of Lactobacillus casei

Rao et al (2009) A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome

Chiba et al (2010) Well-controlled proinflammatory cytokine responses of Peyer’s patch cells to probiotic Lactobacillus casei.

Kobayashi et al (2010) Oral administration of probiotic bacteria, Lactobacillus casei and Bifidobacterium breve, does not exacerbate neurological symptoms in experimental autoimmune encephalomyelitis. I

Serata et al (2012) Roles of thioredoxin and thioredoxin reductase in the resistance to oxidative stress in Lactobacillus casei

Shioiri et al (2006) The effects of a synbiotic fermented milk beverage containing Lactobacillus casei strain Shirota and transgalactosylated oligosaccharides on defecation frequency, intestinal microflora, organic acid concentrations, and putrefactive metabolites of sub-optimal health state volunteers: a randomized placebo-controlled cross-over study

Tiengrim & Thamlikitkul (2012) Inhibitory activity of fermented milk with Lactobacillus casei strain Shirota against common multidrug-resistant bacteria causing hospital acquired infection

Shida et al (2009) Induction of interleukin-12 by Lactobacillus strains having a rigid cell wall resistant to intracellular digestion.

Yasuda et al (2011) Lectin microarray reveals binding profiles of Lactobacillus casei strains in a comprehensive analysis of bacterial cell wall polysaccharides

Matsumoto et al (2009) A component of polysaccharide peptidoglycan complex on Lactobacillus induced an improvement of murine model of inflammatory bowel disease and colitis-associated cancer

Kaji et al (2010) Bacterial teichoic acids reverse predominant IL-12 production induced by certain Lactobacillus strains into predominant IL-10 production via TLR2-dependent ERK activation in macrophages

Uchida K et al (2007) Immunonutritional effects during synbiotics therapy in pediatric patients with short bowel syndrome

Shimizu et al (2009) Synbiotics decrease the incidence of septic complications in patients with severe SIRS: A preliminary report

Bongaerts et al (2006) Lactobacillus fermentum bacteremia in a seriously ill premature short small bowel patient during probiotic Lactobacillus casei therapy

Kanamori et al (2006) Abnormal intestinal microbiota in pediatric surgical patients and the effects of a newly designed symbiotic therapy

Massen & Claassen (2008) Strain-dependent effects of probiotic lactobacilli on EAE autoimmunity

Yasuda et al (2008) Suppressive effect on activation of macrophages by Lactobacillus casei strain Shirota genes determining the synthesis of cell wall-associated polysaccharides

Kanamori et al (2002) A novel synbiotic therapy dramatically improved the intestinal function of a pediatric patient with laryngotracheo-esophageal cleft (LTEC) in the intensive care unit

Kanamori et al (2001) Combination therapy with Bifidobacterium breve, Lactobacillus casei, and galactooligosaccharides dramatically improved the intestinal function in a girl with short bowel syndrome: a novel synbiotics therapy for intestinal failure

Kobayashi et al (2012) Probiotic upregulation of peripheral IL-17 responses does not exacerbate neurological symptoms in experimental autoimmune encephalomyelitis mouse models.

Yuki et al (1999) Gastrointestinal survival of Lactobacillus casei strain Shirota administered in fermented milk products

Shida et al (2006) Essential roles of monocytes in stimulating human peripheral blood mononuclear cells with Lactobacillus casei to produce cytokines and augment natural killer cell activity

Hendriks et al (2000) Simultaneous incubation with Lactobacillus casei Shirota decreases adherence and invasion of Salmonella enteritidis 857 to caco-2 cells

Takeda et al (2006) Interleukin-12 is involved in the enhancement of human natural killer cell activity by Lactobacillus casei Shirota

Holder et al (1993) LC-9018 treatment enhances survival in gram-negative burn wound sepsis

Sutula et al (2012) Culture media for differential isolation of Lactobacillus casei Shirota from oral samples

Ezendam & van Loveren (2008) Lactobacillus casei Shirota administered during lactation increases the duration of autoimmunity in rats and enhances lung inflammation in mice

Setoyama et al (1985) Protective effect of lipoteichoic acid from Lactobacillus casei and Lactobacillus fermentum against Pseudomonas aeruginosa in mice

Tiengrim et al (2012) Viability of Lactobacillus casei strain Shirota (LcS) from feces of Thai healthy subjects regularly taking milk product containing LcS

Hayakawa M et al (2012) Synbiotic therapy reduces the pathological Gram-negative rods caused by an increased acetic acid concentration in the gut

Curto et al (2011) Survival of probiotic lactobacilli in the upper gastrointestinal tract using an in vitro gastric model of digestion

De Preter et al (2011) Impact of the synbiotic combination of Lactobacillus casei Shirota and oligofructose-enriched inulin on the fecal volatile metabolite profile in healthy subjects

Matsuzaki et al (1997) Effect of oral administration of Lactobacillus casei on alloxan-induced diabetes in mice

Matsuzaki et al (1997) Prevention of onset in an insulin-dependent diabetes mellitus model, NOD mice, by oral feeding of Lactobacillus casei

Nanno et al (1989) Increased production of cytotoxic macrophage progenitors by Lactobacillus casei in mice

Morotomi & Mutai (1986) In vitro binding of potent mutagenic pyrolysates to intestinal bacteria

Du Toit E (2013) Assessment of the effect of stress-tolerance acquisition on some basis characteristics of specific probiotics.

Sakai et al (2010) M-RTLV agar, a novel selective medium to distinguish Lactobacillus casei and Lactobacillus paracasei from Lactobacillus rhamnosus.

De Carvalo et al (2009) Evaluation of the role of environmental factors in the human gastrointestinal tract on the behaviour of probiotic cultures of Lactobacillus casei Shirota and Lactobacillus casei LC01 by the use of a semi-dynamic in vitro model

Hernandez-Mendoza et al (2009) Key role of teichoic acids on aflatoxin B1-binding by probiotic bacteria

Kawakami et al (2009) p-Cresol inhibits IL-12 production by murine macrophages stimulated with bacterial immunostimulant

Nissen et al (2009) Gut health promoting activity of new putative probiotic/protective Lactobacillus spp. strains: A functional study in the small intestinal cell model.

Botes et al (2008) Adhesion of the probiotic strains Enterococcus mundtii ST4SA and Lactobacillus plantarum 423 to Caco-2 cells under conditions simulating the intestinal tract, and in the presence of antibiotics and anti-inflammatory medicaments

De Preter et al (2008) Effect of dietary intervention with different pre- and probiotics on intestinal bacterial enzyme activities

Fujimoto et al (2008) Identification and quantification of Lactobacillus casei strain Shirota in human feces with strain-specific primers derived from randomly amplified polymorphic DNA

Magarinos et al (2008) Viability of probiotic micro-organisms (Lactobacillus casei Shirota and Bifidobacterium animals subspp. lactis) in a milk-based dessert with cranberry sauce

Nanno et al (2008) Effect of oral administration Lactobacillus casei Shirota on experimental autoimmune encephalomyelitis in rats

Oishi et al (2008) Effect of probiotics, Bifidobacterium breve and Lactobacillus casei, on Bisphenol A exposure in rats

Ooi et al (2008) Prevention of irinotecan hydrochloride-induced diarrhea by oral administration of Lactobacillus casei strain Shirota in rats

Shima et al (2008) Differential effects of two probiotic strains with different bacteriological properties on intestinal gene expression, with special reference to indigenous bacteria

Sumeri et al (2008) Single bioreactor gastrointestinal tract simulator for study of survival of probiotic bacteria

Alhaj OA, Kanekanian AD, Peters AC (2007) Investigation on whey proteins profile of commercially available milk-based probiotics health drinks using fast protein liquid chromatography (FPLC).

De Preter et al (2007) Effects of Lactobacillus casei Shirota, Bifidobacterium breve and oligofructose-enriched inulin on colonic nitrogen-protein metabolism in healthy humans.

Kato et al (2007) Effect of Lactobacillus casei on the absorption of nifedipine from rat small intestine.

Matsuzaki T et al (2007) Intestinal microflora: probiotics and autoimmunity

Tuohy et al (2007) Survivability of a probiotic Lactobacillus casei in the gastrointestinal tract of healthy human volunteers and its impact on the faecal microflora.

Hayakawa et al (2006) Determination of specific activities and kinetic constants of biotinidase and lipoamidase in LEW rat and Lactobacillus casei (Shirota)

Kanamori et al (2006) Synbiotic therapy: an important supportive therapy for pediatric patients with severe respiratory distress

Makras et al (2006) Kinetic analysis of the antibacterial activity of probiotic lactobacilli towards Salmonella enterica serovar Typhimurium reveals a role for lactic acid and other inhibitory compounds

Maragkoudakis PA et al (2006) Probiotic potential of Lactobacillus strains isolated from dairy products

Srinivasan et al (2006) Clinical safety of a Lactobacillus casei Shirota as a probiotic in critically ill children

Sugawara et al (2006) Perioperative synbiotic treatment to prevent postoperative infectious complications in biliary cancer surgery: A randomized controlled trial

Fayol-Messaoudi et al (2005) pH-, lactic acid-, and non-lactic acid-dependent activities of probiotic lactobacilli against Salmonella enterica Serovar Typhimurium

Gibson et al (2005) An evaluation of probiotic effects in the human gut: microbial aspects

Iyer et al (2005) Release studies of Lactobacillus casei strain Shirota from chitosan-coated alginate-starch microcapsules in ex vivo porcine gastrointestinal contents

Kanazawa et al (2005) Synbiotics reduce postoperative infectious complications: a randomized controlled trial in biliary cancer patients undergoing hepatectomy

De Preter et al (2004) The in vivo use of stable isotope-labelled biomarkers lactose-[15N]ureide and [2H4]tryosine to assess the effects of pro- and prebiotics on the intestinal flora of healthy human volunteers.

Kanamori et al (2004) Experience of long-term synbiotic therapy in seven short bowel patients with refractory enterocolitis

Lee et al (2004) Permanent colonization by Lactobacillus casei is hindered by the low rate of cell division in mouse gut

Ohashi et al (2004) The effect of Lactobacillus casei strain Shirota on the cecal fermentation pattern depends on the individual cecal microflora in pigs

Ohashi et al (2004) Transition of the probiotic bacteria, Lactobacillus casei strain Shirota, in the gastrointestinal tract of a pig

Asahara et al (2003) Assessment of safety of Lactobacillus strains based on resistance to host innate defense

Halttunen et al (2003) Cadmium removal by lactic acid bacteria

Kanamori et al (2003) Anaerobic dominant flora was reconstructed by synbiotics in an infant with MRSA enteritis

Lee et al (2003) Displacement of bacterial pathogens from mucus and Caco-2 cell surface by lactobacilli

Matsuguchi et al (2003) Lipoteichoic acid from Lactobacillus strains elicit strong tumor necrosis factor alpha-inducing activities in macrophages through Toll-like receptor 2

Sakata et al (2003) Influences of probiotic bacteria on organic acid production by pig caecal bacteria in vitro

Styriak et al (2003) Binding of extracellular matrix molecules by probiotic bacteria

Kiwaki & Shimizu-Kadota (2002) Development of genetic manipulation systems and the application to genetic research in Lactobacillus casei strain Shirota

Lee & Puong (2002) Competition for adhesion between probiotics and human gastrointestinal pathogens in the presence of carbohydrate

Lewis et al (2002) Development of an ELISA to detect Lactobacillus casei Shirota in human stool samples

Temmerman et al (2002) Identification and antibiotic susceptibility of bacterial isolates from probiotic products

Kankaanpaa et al (2001) The influence of polyunsaturated fatty acids on probiotic growth and adhesion

Kushiro et al (2001) Lactobacillus casei acquires the binding activity to fibronectin by the expression of the fibronectin binding domain of Streptococcus pyogenes on the cell surface

Ohashi et al (2001) Lactobacillus casei strain Shirota-fermented milk stimulates indigenous lactobacilli in the pig intestine.

Shimizu-Kadota M (2001) A method to maintain introduced DNA sequences stably and safely on the bacterial chromosome: application of prophage integration and subsequent designed excision

Lee et al (2000) Quantitative approach in the study of adhesion of lactic acid bacteria to intestinal cells and their competition with enterobacteria

Ouwehand et al (2000) Adhesion of inactivated probiotic strains to intestinal mucus

Shimizu-Kadota et al (2000) Insertion of bacteriophage phiFSW into the chromosome of Lactobacillus casei strain Shirota (S-1): characterization of the attachment sites and the integrase gene

Tuomola et al (2000) Chemical, physical and enzymatic pre-treatments of probiotic lactobacilli alter their adhesion to human intestinal mucus glycoproteins

El-Nezami et al (1998) Ability of dairy strains of lactic acid bacteria to bind a common food carcinogen, aflatoxin B1

Hamilton-Miller & Shah (1998) Vancomycin susceptibility as an aid to the identification of lactobacilli

Hashimoto et al (1989) Role of culture supernatant of cytotoxic/cytostatic macrophages in activation of murine resident peritoneal macrophages

Kato et al (1998) Suppressive effects of the oral administration of Lactobacillus casei on type II collagen-induced arthritis in DBA/1 mice

Kobayashi et al (1974) Studies on biological characteristics of Lactobacillus II.

Macedo et al (1999) Production and shelf-life studies of low cost beverage with soymilk, buffalo cheese whey and cow milk fermented by mixed cultures of Lactobacillus casei ssp Shirota and Bifidobacterium adolescentis

Morishita et al (1974) Genetic basis of nutritional requirements in Lactobacillus casei.

Nagaoka et al (1990) Structure of polysaccharide-peptidoglycan complex from the cell wall of Lactobacillus casei YIT9018

Nakashima A (1997) Stimulatory effect of phytin on acid production by Lactobacillus casei

Reuter G (1997) Present and future of probiotics in Germany and in Central Europe

Sakata et al (1991) Probiotic preparations dose-dependently increase net production rates of organic acids and decrease that of ammonia by pig cecal bacteria in batch culture

Salminen et al (1996) Clinical uses of probiotics for stabilizing the gut mucosal barrier: successful strains and future challenges

Shimizu-Kadota M (1987) Properties of lactose Plasmid pL Y101 in Lactobacillus casei

Spanhaak et al(1998) The effect of consumption of milk fermented by Lactobacillus casei strain Shirota on the intestinal microflora and immune parameters in humans

Takahashi et al (1991) Phagocytosis of the lactic acid bacteria by M cells in the rabbit Peyer's patches

Tanaka R (1996) The effects of the ingestion of fermented milk with Lactobacillus casei Shirota on the gastrointestinal microbial ecology in healthy volunteers

Tohyama et al (1981) Effect of lactobacilli on urinary indican excretion in gnotobiotic rats and in man

Tuomola EM & Salminen, SJ (1998) Adhesion of some probiotic and dairy Lactobacillus strains to Caco-2 cell cultures

Tuomola et al (1999) The effect of probiotic bacteria on the adhesion of pathogens to human intestinal mucus

Yamagishi et al (1974) Effect of lactobacillus product administration on the anaerobic intestinal flora of aged adults

Yokokura T (1977) Phage receptor material in Lactobacillus casei

Sutula J et al (2012) The effect of a commercial probiotic drink on oral microbiota in healthy denture wearers

Douillard FP et al (2013) Comparative genomic and functional analysis of Lactobacillus casei and Lactobacillus rhamnosus strains marked as probiotics

Douillard FP et al (2013) Comparative genome analysis of Lactobacillus casei strains isolated from Actimel and Yakult products reveals marked similarities and points to a common origin.

Kim S-W et al (2013) Robustness of gut microbiota of healthy adults in response to probiotic intervention revealed by high-throughput pyrosequencing.

Toh H et al (2013) Genomic adaptation of the Lactobacillus casei group

Botta et al (2014) In vitro selection and characterization of new probotic candidates from table olive microbiota.

Melgar-Lalanne G et al (2014) Survival under stress of halotolerant lactobacilli with probiotic properties.

Thomas LV et al (2014) Exploring the influence of the gut microbiota and probiotics on health: a symposium report.

Shokryazdan P et al (2014) Probiotic potential of Lactobacillus strains with antimicrobial activity against some human pathogenic strains

Yasuda E et al (2014) Application of lectin microarray to bacteria including Lactobacillus casei/paracasei strains.

Dieterle ME et al (2014) Exposing the secrets of two well known Lactobacillus casei phages: Genomic and structural analysis of J-1 and PL-1

Bischoff SC et al (2014) Intestinal permeability – a new target for disease prevention and therapy.

Wang R et al (2015) Survival of Lactobacillus casei strain Shirota in the intestines of healthy Chinese adults

Ianniello et al (2015) Aeration and supplementation with heme and menaquinone affect survival to stresses and antioxidant capability of Lactobacillus casei strains

Wang C et al (2015) Intestinal microbiota profiles of healthy pre-school and school-age children and effects of probiotic supplementation

Truong et al (2015) Recovery of Lactobacillus casei strain Shirota (LcS) from the intestine of healthy Vietnamese adults after intake of fermented milk

Utami et al (2015) Recovery of Lactobacillus casei strain Shirota (LCS) from the intestine of healthy Indonesian volunteers after intake of fermented milk and its impact on the Enterobacteriaceae faecal microbiota

Kato-Kataoka et al (2016) Fermented milk containing Lactobacillus casei strain Shirota preserves the diversity of the gut microbiota and relieves abdominal dysfunction in healthy medical students exposed to academic stress.

Karda B et al (2016) To analyse the erosive potential of commercially available drinks on dental enamel and various tooth coloured restorative material – An in vitro study

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