Lactobacillus casei Shirota (LcS) for Stress Gi
Verdict: Published with Warning
Across 6 PubMed studies, the evidence for Lactobacillus casei Shirota (LcS) in Stress Gi grades Tier C — weak evidence. Effective, but with safety or population caveats.
C 🟠 C Weak Evidence Published with Warning
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.47
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Published with Warning
Confidence
65%
Broadly consistent
Evidence level
E3
Single high-quality meta-analysis
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.475
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (6)L2 · primary research & systematic reviews
Efficacy of probiotics on stress in healthy volunteers: A systematic review and meta-analysis based on randomized controlled trials
Finding: Pooled across 7 RCTs probiotics produced a small reduction in subjective stress (SMD = -0.14, 95% CI -0.27 to -0.01, p=0.03) but had no significant effect on cortisol (SMD = -0.02, 95% CI -0.34 to 0.30, p=0.89) or anxiety/depression (SMD = -0.13, 95% CI -0.26 to 0.00, p=0.05); notably zero of the 7 trials used the LcS strain.
View on PubMed Efficacy of Lactobacillus casei Shirota for patients with irritable bowel syndrome
Finding: In the only independent RCT in actual IBS patients, LcS failed the primary endpoint - mean improvement did not reach the 30% MSS threshold for any symptom, and the between-group difference at 16-week follow-up (34+/-7% LcS vs 13+/-8% placebo) was not significant (p=0.06).
View on PubMed Fermented Milk Containing Lactobacillus casei Strain Shirota Preserves the Diversity of the Gut Microbiota and Relieves Abdominal Dysfunction in Healthy Medical Students Exposed to Academic Stress
Finding: Stress-induced rises in stress VAS, total abdominal dysfunction score, and number of >2-fold-changed leukocyte genes were significantly suppressed in the LcS group vs placebo (p<0.05), and species diversity was preserved while Bacteroidaceae rose only in placebo.
View on PubMed Fermented milk containing Lactobacillus casei strain Shirota prevents the onset of physical symptoms in medical students under academic examination stress
Finding: Symptom incidence and total symptom-days were significantly lower with LcS than placebo during weeks 5-6 (p<0.05) and weeks 7-8 (p<0.01), and faecal serotonin was significantly higher two weeks post-exam (p<0.05).
View on PubMed Beneficial effects of Lactobacillus casei strain Shirota on academic stress-induced sleep disturbance in healthy adults: a double-blind, randomised, placebo-controlled trial
Finding: LcS significantly improved OSA sleepiness-on-rising and sleep-length factors, suppressed the stress-induced increase in sleep latency, maintained stage-3 non-REM percentage, and yielded higher delta power than placebo (significant, exact effect sizes not given).
View on PubMed Probiotic Lactobacillus casei strain Shirota relieves stress-associated symptoms by modulating the gut-brain interaction in human and animal models
Finding: Across the pooled human trials, academic-stress-induced rises in salivary cortisol and physical-symptom incidence were significantly suppressed by LcS vs placebo, with rodent data showing LcS pretreatment blunted water-avoidance-stress corticosterone increases (significant; this is a combined mechanistic report reusing the same student cohorts).
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
GRN No. 429 — Lactobacillus casei strain Shirota. Intended Use: As an ingredient in fermented dairy products at a maximum level of 4x10^8 colony forming units per milliliter. FDA Response: has no questions. Notifier: Yakult Honsha Co., Ltd. (Tokyo, Japan). Filed April 10, 2012; closed December 10, 2012. source↗
L4b EU EFSA
Against
The Panel concluded that a cause and effect relationship has not been established between the consumption of Lactobacillus casei Shirota and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences. The Panel considered that there was no human study demonstrating an effect of Lactobacillus casei Shirota consumption on upper respiratory tract infections… source↗
L4c UK NHS
Cautious
Probiotics are generally classed as food rather than medicine, which means they don't go through the rigorous testing medicines do. ... There's some evidence that probiotics may be helpful in some cases, such as helping to ease some symptoms of irritable bowel syndrome (IBS). ... If you have an existing health condition or a weakened immune system, you should talk to a doctor before taking any … source↗
L4d TW TFDA / 衛福部
Supportive
養樂多活菌發酵乳 衛署健食字第A00032號 胃腸功能改善；養樂多300LIGHT活菌發酵乳 衛署健食字第A00128號 免疫調節、輔助調整過敏體質、胃腸功能改善；養樂多300活菌發酵乳 衛署健食字第A00178號 胃腸功能改善 source↗
L4e WHO
Neutral
Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The 2002 FAO/WHO Working Group Guidelines for the Evaluation of Probiotics in Food require strain-level identification (genus, species, strain), in vitro testing (acid/bile tolerance), safety assessment (antibiotic resistance, metabolic activities, no transferable resistance), and… source↗
L5a NIH Office of Dietary Supplements
Neutral
With a total listing of over 500 scientific studies...it is fair to say that the L. casei strain Shirota is the most researched probiotic strain in the world. Classified as Lacticaseibacillus paracasei Shirota since April 2020. source↗
L5d Harvard Health
Neutral
Some research has found that probiotics may help boost mood and cognitive function and lower stress and anxiety. ... It's too early to determine the exact role probiotics play in the gut-brain axis since this research is still ongoing. source↗