Glutamine for Gut Permeability ("Leaky Gut")
There is no convincing evidence that glutamine supplements meaningfully reduce intestinal permeability or treat "leaky gut," a condition major clinics do not recognize as a formal diagnosis. The trial data are conflicting, lean on surrogate markers, and even include a high-dose safety signal in critically ill patients.
Why this grade7-layer evidence engine
The strongest evidence works against a clear benefit. A 2024 systematic review and meta-analysis (PMID 39397201) found no statistically significant overall effect of glutamine on intestinal permeability, with a possible reduction only in a small subgroup taking more than 30 g/day. Those measurements relied on surrogate markers (lactulose/mannitol ratio, zonulin) rather than symptoms or clinical outcomes, so their real-world meaning is uncertain.
One positive signal exists but is fragile. A single-center, double-blind RCT in post-infectious IBS-D (PMID 30108163, n=106) reported a large symptom and permeability improvement on 15 g/day. The effect size (79.6% vs 5.8% response) is implausibly large, the study has not been independently replicated, and it covers a specific patient group rather than general consumers. A separate ICU trial (REDOXS, PMID 23594003, n=1,223) found high-dose IV plus enteral glutamine increased 28-day mortality (adjusted OR 1.28), a serious caution against extrapolating to high doses or critically ill people.
Regulators and clinics reinforce the weak, disputed grade. The FDA approves glutamine only as a sickle cell drug, and EFSA rejected gut and permeability claims, finding no established cause-and-effect relationship. Mayo Clinic states 'leaky gut' is not a recognized diagnosis with no validated test, Harvard calls its disease links controversial, and only Cleveland Clinic offers a cautious 'may help' that runs against this consensus, which is why the verdict lands at weak and disputed rather than positive.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸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 = 0.412
- 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 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status