Lactic acid bacteria is a functional group of bacteria. The term is used by Food microbiologists as a collective term for bacteria able to ferment carbohydrates in foods to lactic acid. They typically occur spontaneously in fermented foods and consist of several different bacterial families and genus such as the family Lactobacillaceae and the genus Lactobacillus.

Lactobacillus is a genus of bacteria consisting of more than 90 defined species, all able to ferment

carbohydrates into carboxylic acids, mainly lactic acid. The Lactobacillus species have been divided into three functional groups based on fermentation function; Group I (obligate homofermentative) which ferments hexoses to lactic acid but cannot ferment gluconate or pentoses, Group II (facultative heterofermentative) which in addition to hexose also ferments pentoses and/or gluconate and finally Group III (obligate heterofermentative) which ferments hexoses to lactic acid, acetic acid and or ethanol and carbon dioxide.

Lactobacillus rhamnosus GG ATCC 53103 – >800 scientific studies, >200 clinical trials (1), 7 ongoing clinical trials.

Lactobacillus rhamnosus is a species within the Lactobacillus genus with a wide variety of strains isolated from different environments including the human gastrointestinal tract. It belongs to group II of Lactobacillus and as such exclusively ferments hexoses into lactid acid but can also ferment pentoses and/or gluconates into lactic and acetic acid. Its pan-genome contains 4711 genes of which 2164 constitute its core genome. The accessory genome allows for wide strain specific functionalities and contains strain specific genes encoding for carbohydrate transport, extracellular polysaccharides, biosynthesis and pili production.

The strain was isolated in 1983 from the intestinal tract. Since its discovery, the strain has been studied extensively on various health benefits and is claimed to the world’s most studied probiotic bacterium with more than 800 studies. The bacteria display a specific pili (hair-like structure on bacterial surfaces important for adhesion) which has been shown to be important to adhesion to the human intestinal wall (2).

• Immune function (1), (3)
• Normalizes intestinal permeability (4)
• Dysbiosis (1)
• Antibiotic-associated Diarrhea (AAD) (1)
• Functional GI disorders in children (5)
• IBS (6)
• Diarrhea (1)
• Allergy (9) and atopic disease (9)

• Gawronska et al (5) found that RR was 33% compared with 5% in placebo in a 4-week study with 37 subjects. Francavilla et al found reduction of frequency and severity of abdominal pain in a 12-week study with 48 children. Kajander et al (7, 8) found improvement in symptoms in two studies of 103 respective 86 subjects.

1. I-Health Inc 2013. Selected Lactobacillus rhamnosus GG Research Abstracts
2. Leeber et al 2011. Functional Analysis of Lactobacillus rhamnosus GG Pili in Relation to Adhesion and Immunomodulatory Interactions with Intestinal Epithelial Cell. Applied and environmental microbiology.
3. Hojsak I, et al. 2010. Lactobacillus GG in the prevention of gastrointestinal and respiratory tract infections in children who attend day care centers: a randomized, double-blind, placebo-controlled trial. Clin. Nutr. 29:312–316. 16.
4. Isolauri E, Majamaa H, Arvola T, et al. Lactobacillus casei strain GG reverses increased intestinal permability induced by cow milk in sukling rats. Gastroenterology. 1993;105:1643–1650.
5. Gawronska A, Dziechciarz P, Horvath A, et al. A randomized double-blind placebo-controlled trial of Lactobacillus GG for abdominal pain disorders in children. Aliment Pharmacol Ther. 2007;25:177–184.

6. Francavilla R, Miniello V, Magista` AM, et al. A randomized controlled trial of Lactobacillus GG in with functional abdominal pain. Pediatrics. 2010;126: e1445–e1452.
7. KajanderK, HatakkaK, PoussaT, et al. A probiotic mixture alleviates symptoms in irritable bowel syndrome patients: a controlled 6-month intervention. Aliment PharmacolTher. 2005;22:387–394.
8. KajanderK, Krogius-KurikkaL, RinttiläT, et al. Effects of multispecies probiotic supplementation on intestinal microbiota in irritable bowel syndrome. Aliment PharmacolTher. 2007;26:463–473. 236. 9.
9. Kalliomäki M, et al. 2001. Probiotics in primary prevention of atopic disease: a randomised placebo-controlled trial. Lancet 357:1076 –1079.
10. Capurso, Lucio. Thirty years of Lactobacillus rhamnosus GG A review. Journal of Clinical Gastroenterology Volume 53, supp. 1 March 2019