Entry 1
Probiotic science page
Uses pili-mediated gut adhesion and soluble immune factors to shorten infectious diarrhea in children and reduce antibiotic-associated diarrhea, with RCT and meta-analysis support.
Overview
LGG was isolated in 1983 from a healthy human gut. The isolators were Gorbach and Goldin [7]. It is one of the most studied probiotic strains. Over 200 clinical trials have tested it. Multiple systematic reviews cover its effects on gastroenteritis, antibiotic-associated diarrhea, atopic disease, and respiratory infections [1][2]. LGG sticks strongly to gut mucus and to the cells lining the gut. Hair-like structures called pili drive this sticking [3].
Mechanism
LGG sticks to the gut wall using hair-like structures called pili [3]. These pili are unique to LGG. Most L. rhamnosus strains do not have them [2]. By sticking to the gut wall, LGG blocks harmful bacteria by taking up space. This helps LGG stay in the gut longer [3]. LGG also releases soluble factors. These strengthen the gut barrier and tune the immune system [1].
Health Benefits
LGG shortens acute infectious diarrhea in children by about 1 day (RCT; meta-analysis) [1][2]. It lowers the rate of antibiotic-associated diarrhea (RCT; multiple meta-analyses) [1][5]. ESPGHAN guidelines conditionally recommend LGG to prevent necrotizing enterocolitis in preterm infants (RCT; guideline) [4]. Evidence on perinatal use for atopic dermatitis prevention is mixed. Some RCTs show benefit in high-risk groups [1]. Evidence level: RCT meta-analysis for gastroenteritis and AAD.
Biology
Originally named Lactobacillus rhamnosus. It was reclassified as Lacticaseibacillus rhamnosus in 2020 [6]. It is Gram-positive. It grows with or without oxygen. It does not form spores. It is a rod-shaped bacterium. It produces only lactic acid from sugar. The lactic acid is the L(+) form. It lives in the human gut. Genome size is about 3.0 Mb. GC content is about 46.8% [2].
Bibliography
Szajewska H, Konarska Z, Kolodziej M. (2016). Probiotic Bacterial and Fungal Strains: Claims with Evidence. Dig Dis. 34(3):251-259. PMID: 27028756
Kankainen M, Paulin L, Tynkkynen S, et al. (2009). Comparative genomic analysis of Lactobacillus rhamnosus GG reveals pili containing a human-mucus binding protein. Proc Natl Acad Sci U S A. 106(40):17193-17198. PMID: 19805152
Reunanen J, von Ossowski I, Hendrickx AP, et al. (2012). Characterization of the SpaCBA pilus fibers in the probiotic Lactobacillus rhamnosus GG. Appl Environ Microbiol. 78(7):2337-2344. PMID: 22247175
van den Akker CHP, van Goudoever JB, Shamir R, et al. (2020). Probiotics and Preterm Infants: A Position Paper by ESPGHAN. J Pediatr Gastroenterol Nutr. 70(5):664-680. PMID: 32332478
Zemla M, Kotowska-Babol M, Szajewska H. (2026). An update on probiotics in paediatrics. Curr Opin Clin Nutr Metab Care. 29(3):320-326. PMID: 41334956
Zheng J, Wittouck S, Salvetti E, et al. (2020). A taxonomic note on the genus Lactobacillus... Int J Syst Evol Microbiol. 70(4):2782-2858. PMID: 32293557
Pace F, Pace M, Quartarone G. (2015). "Probiotics in digestive diseases: focus on Lactobacillus GG." Minerva Gastroenterol Dietol. 61(4):251-263. PMID: 26657927
Available Products
LGG is the active ingredient in Culturelle (i-Health/DSM). It comes in capsules and sachets. It is also in Valio Gefilus products (Valio Ltd, Finland). Many generic versions exist worldwide. Deposited as ATCC 53103.