30 Years of Probiotic Research – LGG Still on Top

We recently introduced the single strain probiotic L.Rhamnosus GG (LGG) into our range.  The research for this particular strain has a wide remit and below we venture into some of the studies and applications of LGG from the past 30 years.

Lactobacillus GG (LGG) is clearly the world’s most clinically studied probiotic. The World Health Organisation’s (WHO) definition of a probiotic is a “live microorganisms which when administered in adequate amounts confer a health benefit on the host”.  LGG itself was first isolated in the late ‘80s from the faecal sample of a healthy adult by the researchers Gordon and Gorbach, hence the ‘GG’ moniker.

Surviving the journey

During the early studies and subsequently confirmed by multiple others, LGG is known to withstand gastric acidity and bile salts and effectively adheres to the gastrointestinal mucosa. LGG’s ability to resist gastric acidity and bile salts is a consequence of the ability of the bacterium to produce anti-stress proteins that give it greater survival capacity in intestinal transit after oral intake. Adherence to the intestinal wall is also favoured by the presence on the bacterial wall of exopolysaccharides rich in galactose residues and the presence of specific adhesive pili.


LGG has a well-studied effect on the immune system which is explained by the stimulation and production of different cytokines such as TNF-α, IL-1β, IL-6, IL-10, IL-12, IFN-γ and a particular protein, p40, secreted by LGG cells that can reduce the inflammatory state and apoptosis of intestinal epithelial cells. Therefore, LGG is well understood, characterised and it is known to have several useful anti-inflammatory effects.


On the base of these and other functional properties that distinguish it from other probiotics, LGG can achieve significant results in the different situations characterised by microbiota dysbiosis. Dysbiosis occurs when bacterial homeostasis is disrupted because of an imbalance of microbiota composition, a change in metabolic activities and an altered distribution of bacteria in the intestine. Based on these elements, dysbiosis shows 3 characteristics:

  1. Numeric loss of beneficial bacteria
  2. Overgrowth of potentially pathogenic bacteria
  3. Loss of bacterial diversity

In most cases, these 3 types of dysbiosis occur simultaneously. A typical example of dysbiosis is seen after the use of antibiotics that cause dysregulation of normal bacterial flora, with an overgrowth of potentially pathogenic and toxic microorganisms, leading to a rapid and significant drop in taxonomic wealth, uniformity, and diversity.

The mechanisms of action of LGG such as enhancement of the epithelial barrier increased adhesion to the intestinal mucosa, concomitant inhibition of pathogen adhesion, competitive exclusion of pathogenic microorganisms, production of anti-micro-organism substances, and modulation of the immune system are the reasons why it is so frequently selected by practitioners as the number one candidate probiotic for the prevention and treatment of every cause of dysbiosis.

Neuropsychiatric Disorders in late childhood (RCT)

For some time now there has been a growing body of supportive evidence that the relationship between the bacteria in our digestive tract and our central nervous system may not be as tenuous as some may like to think. In a study published in Pediatric Research, a retrospective review of data in a small but informative group of children indicates there may be a positive relationship between the use of a well-studied probiotic and the reduced risk of developing a neuropsychiatric illness.

The author’s results suggest that oral supplementation during early infancy with Lactobacillus rhamnosus GG (ATCC 53103) might actually offset the risk of diagnoses such as attention deficit hyperactivity disorder (ADHD) and/or Asperger syndrome (AS) being received up to 13 years later and is something worth exploring further. Whilst this is an example of early work with a number of unknowns, it is well understood that LGG has a strong and long safety profile and is well tolerated by infants through the mixing of the organisms with breast milk or formula, as well as in other mediums ahead of simply swallowing the capsules.

The paper states – Data demonstrate that early administration of Lactobacillus rhamnosus GG may reduce the risk of ADHD and AS. Lactobacillus rhamnosus GG has been shown to stabilize the gut permeability barrier by effects on tight junctions, mucin production and antigen-specific immunoglobulin A production. In addition, a recent experimental study has demonstrated that Lactobacillus rhamnosus regulates, again via the vagus nerve, emotional behaviour and the central GABAergic system, which is also associated with neuropsychiatric disorders.

Interestingly they found that probiotics had no significant effect on microbiota composition in the study suggesting that the effects on the central nervous system were either induced by altered vagal afferent signalling or by systemic metabolic changes related to probiotic intake.

They conclude….our findings demonstrate a possible preventive risk-reducing effect of a probiotic LGG on later development of ADHD and AS. We also report an interconnection between the early gut microbiota and development of these neuropsychiatric disorders, although no single constant microbiota composition component or change was detected. However, keeping in mind the above-mentioned limitations of the study, we consider the findings preliminary but encouraging for further studies of the subject both in the area of well-powered clinical trials and experimental research.

In conclusion

From children to seniors and all in between, multiple applications are either well recognised or are becoming clearer as data sets increase.  Whilst numerous other bacterial strains are coming to market with narrow ranges of function and focus, LGG remains a primary point of intervention for gastrointestinal dysbiotic events.

Nutrigold L. Rhamnosus GG is a single strain product consisting of 60 vegan capsules each containing 25 Billion CFUs. LGG (Lactobacillus GG) is an extensively studied strain of friendly intestinal bacteria, naturally occurring in the digestive tract. Lactobacillus GG is a specific strain of the species Lactobacillus rhamnosus, discovered and patented by researchers Drs. Gorbach and Goldin at Tufts University. To date, this is the best-studied and most extensively documented probiotic lactic acid bacteria strain in the world. Vegan, Gluten-Free, Allergen-Free



Claes IJ, Schoofs G, Regulski K, et al. Genetic and biochemical characterization of the cell wall hydrolase activity of the major secreted protein of Lactobacillus rhamnosus GG. PLoS One. 2012;7(2):e31588. doi:10.1371/journal.pone.0031588

Khailova L, Baird CH, Rush AA, Barnes C, Wischmeyer PE. Lactobacillus rhamnosus GG treatment improves intestinal permeability and modulates inflammatory response and homeostasis of spleen and colon in experimental model of Pseudomonas aeruginosa pneumonia. Clin Nutr. 2017;36(6):1549-1557. doi:10.1016/j.clnu.2016.09.025

Lebeer S, Verhoeven TL, Francius G, et al. Identification of a Gene Cluster for the Biosynthesis of a Long, Galactose-Rich Exopolysaccharide in Lactobacillus rhamnosus GG and Functional Analysis of the Priming Glycosyltransferase. Appl Environ Microbiol. 2009;75(11):3554-3563. doi:10.1128/AEM.02919-08

Goldin BR, Gorbach SL, Saxelin M, Barakat S, Gualtieri L, Salminen S. Survival of Lactobacillus species (strain GG) in human gastrointestinal tract. Dig Dis Sci. 1992;37(1):121-128. doi:10.1007/BF01308354

Capurso L. Thirty Years of Lactobacillus rhamnosus GG: A Review. J Clin Gastroenterol. 2019;53 Suppl 1:S1-S41. doi:10.1097/MCG.0000000000001170

Mantegazza C, Molinari P, D’Auria E, Sonnino M, Morelli L, Zuccotti GV. Probiotics and antibiotic-associated diarrhea in children: A review and new evidence on Lactobacillus rhamnosus GG during and after antibiotic treatment. Pharmacol Res. 2018;128:63-72. doi:10.1016/j.phrs.2017.08.001

Szajewska H, Horvath A. Lactobacillus rhamnosus GG in the Primary Prevention of Eczema in Children: A Systematic Review and Meta-Analysis. Nutrients. 2018;10(9):1319. Published 2018 Sep 18. doi:10.3390/nu10091319

Savino F, Montanari P, Galliano I, Daprà V, Bergallo M. Lactobacillus rhamnosus GG (ATCC 53103) for the Management of Infantile Colic: A Randomized Controlled Trial. Nutrients. 2020;12(6):E1693. Published 2020 Jun 5. doi:10.3390/nu12061693

Pärtty A. et al. A possible link between early probiotic intervention and the risk of neuropsychiatric disorders later in childhood – a randomized trial. Pediatr Res. 2015 Mar 11

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1 Comment. Leave new

  • Very enlightening and to the point. Will you be doing any further articles on probiotics in a similar vein


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Elisabeth Philipps

Karen Devine

Karen Devine

Shelley Harvey

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