Lactobacillus paracasei (K71 / LP33) for Immune Elderly
Verdict: Published with Warning
Across 7 PubMed studies, the evidence for Lactobacillus paracasei (K71 / LP33) in Immune Elderly 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 0.46
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Published with Warning
Confidence
77%
Broadly consistent
Evidence level
E1
Cochrane high-quality SR/MA
▸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 = 0.461
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- 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 (7)L2 · primary research & systematic reviews
Probiotics for preventing acute upper respiratory tract infections
Finding: Probiotics (any strain) reduced the number of people with at least one acute URTI vs placebo, RR 0.76 (95% CI 0.67-0.87, p<0.001), but GRADE certainty was only LOW and the review is strain-agnostic and not elderly-specific.
View on PubMed Probiotics for the Prevention of Acute Respiratory-Tract Infections in Older People: Systematic Review
Finding: Across 8 RCTs in older people, certain strains (e.g. CNCM I-1518) lowered URTI incidence/duration but not all strains were effective and not all trials reached statistical significance; no pooled effect size was reported.
View on PubMed Effects of a Fermented Dairy Drink Containing Lacticaseibacillus paracasei subsp. paracasei CNCM I-1518 and the Standard Yogurt Cultures on the Incidence, Duration, and Severity of Common Infectious Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Finding: Strain CNCM I-1518 modestly reduced odds of experiencing at least one CID (OR 0.81, 95% CI 0.66-0.98, p=0.029) but had no significant effect on CID duration or severity; this is a different strain than LP33/K71 and a general, non-elderly population.
View on PubMed Effect of Lactobacillus paracasei subsp. paracasei, L. casei 431 on immune response to influenza vaccination and upper respiratory tract infections in healthy adult volunteers: a randomized, double-blind, placebo-controlled, parallel-group study
Finding: Large RCT: L. casei 431 had NO effect on the primary immune/vaccine-response endpoint (null on seroprotection, seroconversion and titers); a secondary endpoint showed shorter URTI symptom duration (6.4 vs 7.3 days, p=0.0059).
View on PubMed Yogurt supplemented with probiotics can protect the healthy elderly from respiratory infections: A randomized controlled open-label trial
Finding: Probiotic yogurt (strain N1115) reduced acute URTI risk in the elderly, RR 0.55 (95% CI 0.307-0.969, p=0.030), but the trial was open-label, industry-funded, used a different strain than LP33/K71, and enrolled from age 45.
View on PubMed The effects of non-viable Lactobacillus on immune function in the elderly: a randomised, double-blind, placebo-controlled study
Finding: The only L. paracasei RCT directly in elderly immunity was NULL overall: no significant effect of MCC1849 on vaccine antibody response or immune parameters; only an exploratory subgroup aged 85+ (n=27) showed a signal for A/H1N1 and B.
View on PubMed Efficacy and safety of the probiotic Lactobacillus paracasei LP-33 in allergic rhinitis: a double-blind, randomized, placebo-controlled trial (GA2LEN Study)
Finding: The only RCT of the actual LP-33 strain studied ALLERGIC RHINITIS, not elderly immunity: RQLQ barely improved (diff -0.286, p=0.0255) while the nasal symptom primary score was non-significant (p=0.13); evidence is off-population and off-outcome for this claim.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L5a NIH Office of Dietary Supplements
Cautious
A review of 23 studies (1,919 participants) in which probiotics were tested for treating allergic rhinitis found some evidence that they may be helpful for improving symptoms and quality of life... because the studies tested different probiotics and measured different effects, no recommendations about the use of probiotics could be made. source↗