Lactobacillus Rhamnosus for Kids' Diarrhea: Does It Work?

observational-study PMID: 34183579

Lactobacillus Rhamnosus for Kids' Diarrhea: Does It Work?

Quick Summary: A 2021 study looked at whether the probiotic Lactobacillus rhamnosus helps kids with acute gastroenteritis (stomach flu causing diarrhea) and if it matters how long or severe the symptoms were before starting it. Researchers analyzed data from two trials with nearly 1,800 young children and found no benefits from the probiotic compared to a placebo, no matter the starting severity. This suggests it doesn't shorten diarrhea or ease symptoms in these cases.

What The Research Found

This study tested if Lactobacillus rhamnosus (a common "good bacteria" in probiotics) could fight diarrhea in kids with stomach bugs. The big takeaway? It didn't make a difference. Kids who took the probiotic had the same rates of severe symptoms, diarrhea length, and doctor visits as those who got a fake pill (placebo).

Key results in simple terms:
- About 18% of kids in both groups developed moderate-to-severe symptoms after treatment—no edge for the probiotic.
- Diarrhea lasted the same amount of time, whether symptoms started less than a day ago or more than three days ago.
- No drop in hospital stays or extra doctor trips.
- Even splitting kids by how often they had diarrhea (3 or fewer times a day vs. 6 or more), the probiotic didn't help more in tougher cases.

In short, the probiotic's lack of effect wasn't because parents waited too long to give it—timing and severity didn't change the outcome.

Study Details

Who was studied: 1,770 kids aged 3 to 48 months (that's toddlers to young preschoolers) who went to emergency rooms in 16 North American hospitals with acute gastroenteritis. These were real cases of vomiting and diarrhea from infections, not mild tummy troubles.
How long: The original trials ran for a short time after ER visits, tracking symptoms for days to weeks. This analysis reviewed data from kids grouped by symptom start: under 24 hours, 24-72 hours, or 72+ hours before treatment.
What they took: Half the kids got Lactobacillus rhamnosus GG (a single-strain probiotic) or a combo with Lactobacillus helveticus. The other half got a placebo. Exact doses weren't detailed, but it was given as part of standard trial products, like powders or capsules mixed into food—common for kid probiotics.

Doctors used a scoring system (Modified Vesikari Scale) to measure if symptoms hit "moderate-to-severe" levels, like lots of watery stools or dehydration risks.

What This Means For You

If your child has bad diarrhea from a stomach bug, this study says Lactobacillus rhamnosus probiotics probably won't speed up recovery or cut down on misery, even if you start them early. Don't rely on them as a quick fix—instead, focus on proven steps like keeping your kid hydrated with oral rehydration solutions (like Pedialyte), watching for dehydration signs (dry mouth, fewer wet diapers), and calling the doctor if it worsens.

For parents searching "best probiotics for kids diarrhea," this adds to evidence that not all probiotics work for every gut issue. Talk to your pediatrician before trying any, especially in ER-level sickness. It might help for other things like antibiotic-related diarrhea, but here, it's a pass.

Study Limitations

This wasn't a brand-new experiment—it was a deeper look at two earlier trials, so it can't prove cause-and-effect as strongly. Doses weren't spelled out, so results might differ with stronger or weaker products. It only covered North American ER kids, so it may not fit milder home cases or kids in other countries. Plus, mixing single-strain and combo probiotics could blur what works best for Lactobacillus rhamnosus alone. Always check with a doctor for your child's needs—these findings don't cover everyone.

Key Findings

This secondary analysis of two randomized trials found no significant difference in outcomes between children with acute gastroenteritis treated with Lactobacillus rhamnosus GG (LGG) or a combination probiotic (LGG + L. helveticus) versus placebo. The study concluded that probiotic efficacy was not influenced by baseline diarrhea duration or severity.

Study Design

Type: Preplanned secondary analysis of two randomized, placebo-controlled trials.
Population: 1,770 children aged 3–48 months presenting to 16 North American emergency departments (EDs) with acute gastroenteritis.
Severity Criteria: Participants were stratified by diarrhea duration (<24, 24–72, ≥72 hours) and frequency (≤3, 4–5, ≥6 episodes/24 hours).
Primary Outcome: Development of moderate-to-severe gastroenteritis (Modified Vesikari Scale score ≥9) post-treatment.
Secondary Outcomes: Diarrhea duration, frequency, unscheduled healthcare visits, and hospitalization.

Dosage & Administration

The study summary does not specify exact doses of Lactobacillus rhamnosus or the combination product. Probiotics were administered as part of two distinct formulations evaluated in the parent trials, but details on strain ratios, colony-forming units (CFUs), or delivery methods (e.g., capsules, powder) are omitted.

Results & Efficacy

Primary Outcome: No difference in moderate-to-severe gastroenteritis between probiotic (18.4%, 162/882) and placebo groups (18.3%, 162/888) (risk ratio: 1.00; 95% CI: 0.87–1.16; P = 0.95).
Secondary Outcomes:
Diarrhea Duration: No interaction between baseline severity and treatment (P = 0.88).
Maximum Diarrhea Episodes: No significant effect (P = 0.87).
Unscheduled Visits: P = 0.21.
Hospitalization: P = 0.87.
Subgroup Analysis: Efficacy did not vary by symptom duration or frequency (all P > 0.05).

Limitations

Secondary Analysis: Findings are post hoc, limiting causal inference compared to primary trial objectives.
Lack of Dose Details: Absence of specific dosing information restricts interpretation of strain potency.
Observational Nature: Despite originating from RCTs, this analysis is observational, introducing potential confounding.
Population Specificity: Results apply to ED-presenting children in North America; generalizability to other settings or populations is uncertain.
Heterogeneous Probiotic Products: Combined analysis of LGG alone and a multi-strain formulation may obscure individual strain effects.

Clinical Relevance

For parents and clinicians, this study suggests Lactobacillus rhamnosus-based probiotics do not reduce diarrhea duration or severity in children with acute gastroenteritis, regardless of symptom timing or frequency. The lack of interaction between baseline severity and treatment implies early or late administration does not alter outcomes. These findings align with growing evidence questioning the universal efficacy of probiotics in ED settings, emphasizing the need for targeted approaches or alternative therapies. Users should consider strain-specific research and consult guidelines, as this study does not support routine use of LGG or LGG + L. helveticus for moderate-to-severe diarrhea in this demographic.

Source: PubMed (2021)