Benefits
Digestive support during antibiotic use in children
A meta-analysis of LGG trials (11 trials, 1,308 people) found antibiotic-related diarrhea in 12.3% versus 22.4% with placebo or no added treatment, significant in children (moderate-quality evidence) but not in adults overall. A Cochrane review pooled across strains found 8% versus 19% in children, and ESPGHAN strongly recommends LGG for at-risk children if a probiotic is used.
Digestive recovery in young children: hospital and emergency trials
In an Indian hospital trial in 559 children with acute watery diarrhea, LGG with rehydration shortened diarrhea and hospital stays compared with rehydration alone, without a placebo. A US placebo-controlled trial in 971 young children with gastroenteritis found no difference in severity, diarrhea length or vomiting, and ESPGHAN gives LGG only a weak recommendation for this use.
Digestive and respiratory health in hospitalized children
In a placebo-controlled trial in 742 hospitalized children, LGG at 1 billion CFU a day in fermented milk lowered the risk of hospital-acquired digestive infections (RR 0.40) and respiratory infections (RR 0.38); hospital stay length did not change. An ESPGHAN working group recommends LGG if a probiotic is used to prevent hospital diarrhea in children.
Upper respiratory health in children attending daycare
In a 3-month placebo-controlled trial in 281 daycare children, LGG in fermented milk lowered the risk of upper respiratory infections (RR 0.66). In a 7-month trial in 571 Helsinki daycare children, LGG milk led to 16% fewer sick days, with no significant difference after adjusting for age.
Infant skin health in allergy-prone families
In a Finnish trial, LGG given to mothers before birth and to infants for 6 months halved atopic eczema by age 2 (23% versus 46%), and the gap held at age 4. A German trial using the same strain found no difference (28% versus 27%) and more wheezing episodes with LGG, so the effect has not been reproduced.
Abdominal pain in children with functional gut complaints
A pooled analysis of 3 trials in 290 children with recurring abdominal pain found more responders with LGG than placebo (RR 1.31), with the clearest effect in children with IBS. There was no difference for functional abdominal pain or functional dyspepsia alone.
Mechanism of action
SpaCBA pili and mucus binding
LGG carries hair-like pili built from SpaC, SpaB and SpaA proteins. Lab work showed that the SpaC tip protein binds human intestinal mucus and that LGG lost its mucus binding when the spaC gene was switched off, which may help explain why LGG lingers in the gut longer than a related strain.
p40 and p75 proteins and gut lining cells
In cell and mouse colon tissue studies, two proteins secreted by LGG, p40 and p75, activated the survival signal Akt, protected gut lining cells from damage caused by inflammatory signals and supported cell growth. These are laboratory findings, not human results.
Survival through stomach acid and bile
A 30-year review notes that LGG was patented because it survives and grows at stomach acid pH and in bile and sticks to gut lining cells, traits that let it reach the intestine alive when taken by mouth.
Clinical trials
Randomized, double-blind, placebo-controlled trial; LGG at 1 billion CFU a day in 100 mL fermented milk versus the same milk without LGG, for the hospital stay (Hojsak et al. 2010, Pediatrics)
742 hospitalized children randomized to LGG (n=376) or placebo (n=366).
LGG lowered the risk of hospital-acquired digestive infections (RR 0.40; NNT 15), respiratory infections (RR 0.38; NNT 30), vomiting episodes (RR 0.5) and diarrhea episodes (RR 0.24). Hospital stay length did not differ.
Randomized, double-blind, placebo-controlled trial (NCT01773967) at 10 US pediatric emergency departments; LGG 10 billion CFU twice daily for 5 days; diarrhea duration (median 49.7 versus 50.9 hours) was a secondary outcome that did not differ (Schnadower et al. 2018, N Engl J Med)
971 children aged 3 months to 4 years with acute gastroenteritis; 943 completed
No difference on the primary outcome: moderate-to-severe gastroenteritis occurred in 11.8% on LGG and 12.6% on placebo (RR 0.96, P=0.83). Vomiting, daycare absence and household spread also did not differ. Funded by a US National Institutes of Health institute and others.
Randomized, double-blind, placebo-controlled trial (NCT01853124); R0011 with R0052 at 4 billion CFU twice daily for 5 days, registered as Lacidofil (Freedman et al. 2018, N Engl J Med)
886 children aged 3 to 48 months at six Canadian pediatric emergency departments
Moderate-to-severe gastroenteritis within 14 days: 26.1% on the active product vs 24.7% on placebo (P=0.72). Symptom duration, unscheduled visits and adverse events did not differ. It did not test the GG strain. Funded by CIHR and others; Institut Rosell Lallemand is a registered collaborator.
Randomized, double-blind, placebo-controlled trial; LGG given to mothers before delivery and to their infants for 6 months after birth (Kalliomäki et al. 2001, Lancet)
Families with a close relative who had eczema, allergic rhinitis or asthma; 132 children assessed at age 2
Atopic eczema was diagnosed in 23% of the LGG group versus 46% on placebo (RR 0.51). At the 4-year follow-up it was 14 of 53 versus 25 of 54 children (RR 0.57). A later German trial of the same strain found no effect.
Randomized, controlled, blinded trial; oral rehydration alone, or plus LGG 10 billion or 1 trillion CFU twice daily for at least 7 days or until diarrhea stopped (Basu et al. 2009, J Clin Gastroenterol)
559 children admitted to hospital with acute watery diarrhea: 185 controls, 188 and 186 on the two LGG doses
Both LGG doses lowered diarrhea frequency and duration, the need for IV fluids and hospital stay compared with rehydration alone, with no difference between the two doses. No complications were seen. The control group did not get a placebo.
Systematic review and meta-analysis of 12 randomized controlled trials (1,499 participants) of LGG versus placebo or no added treatment in people taking antibiotics, graded with GRADE (Szajewska et al. 2015, Aliment Pharmacol Ther)
Children and adults taking antibiotics; 11 trials with 1,308 participants in the main analysis
Antibiotic-associated diarrhea fell from 22.4% to 12.3% with LGG (RR 0.49; low quality of evidence). The reduction was significant in children (5 trials, 445 participants, RR 0.48; moderate quality) but not in adults overall (6 trials, 863 participants, RR 0.48), except in a subset taking antibiotics for H. pylori eradication.
Randomized, double-blind, placebo-controlled trial; LGG 5 billion CFU twice daily from 4 to 6 weeks before delivery and for 6 months after birth (Kopp et al. 2008, Pediatrics)
105 pregnant women from families with allergic disease; 94 families completed
Atopic dermatitis at age 2 was 28% with LGG and 27.3% with placebo (RR 0.96), with no difference in severity. Recurrent wheezing bronchitis was more common with LGG (26% versus 9.1%).
Randomized, double-blind, placebo-controlled trial; milk with or without LGG for 7 months, average 260 mL a day (Hatakka et al. 2001, BMJ)
571 healthy children aged 1 to 6 in 18 Helsinki daycare centers
Children on LGG milk had 16% fewer days absent for illness (4.9 versus 5.8 days) and 17% fewer had respiratory infections with complications. After adjusting for age, these differences were no longer statistically significant; the authors called the effects modest.
Meta-analysis of 3 randomized controlled trials of LGG in children with abdominal pain-related functional gut disorders (Horvath et al. 2011, Aliment Pharmacol Ther)
290 children; 167 in the IBS subgroup
LGG raised the share of children whose pain eased (RR 1.31; NNT 7), more so in IBS (RR 1.70; NNT 4). No difference for functional abdominal pain or functional dyspepsia alone.
Randomized, double-blind, placebo-controlled trial; LGG at 1 billion CFU in 100 mL fermented milk versus the same post-pasteurized milk without LGG, for 3 months; gastrointestinal infections (RR 0.63), vomiting and diarrheal episodes did not differ significantly from placebo (Hojsak et al. 2010, Clin Nutr)
281 children attending daycare centers (139 LGG, 142 placebo)
LGG lowered the risk of upper respiratory tract infections (RR 0.66; NNT 5) and of respiratory infections lasting more than 3 days (RR 0.57), with fewer days of respiratory symptoms. Lower respiratory tract infections did not differ.