Glucomannan / Konjac Glucomannan (KGM) for Cholesterol
Glucomannan (konjac glucomannan), a viscous soluble fiber, modestly lowers total and LDL ("bad") cholesterol at roughly 3-4 g per day, but the supporting trials are short and it is no substitute for diet, lifestyle, or statin therapy. The evidence is rated preliminary (Tier B): consistent and biologically plausible, yet limited by short study durations and a lack of long-term heart-outcome data.
Why this grade7-layer evidence engine
The grade rests on two independent, good-quality meta-analyses that point the same way. Sood 2008 (PMID 18842808; 14 trials, n=531) found glucomannan cut total cholesterol by about 19 mg/dL and LDL by about 16 mg/dL, with HDL and triglycerides unchanged. Ho 2017 (PMID 28356275; 12 trials, n=636) similarly reported LDL dropping roughly 0.35 mmol/L (~16%) plus lower non-HDL and ApoB. Smaller randomized trials agree: PMID 7872224 showed a 7% LDL fall at 3.9 g/day, and PMID 10857960 a larger 22% drop at higher doses.
Regulators and clinics are split, which keeps this at preliminary rather than strong. Europe's EFSA formally authorized a health claim that glucomannan helps maintain normal blood cholesterol at 4 g/day, but the US FDA has approved no such claim, and WHO/JECFA addresses only food-additive safety, not cholesterol benefit. Cleveland Clinic stays cautious, noting that effects seen in lab studies still need confirmation in people; Mayo, Harvard, and the National Lipid Association endorse viscous soluble fibers generally without singling out glucomannan.
The main limits are duration and scope: most trials ran only 3-12 weeks, doses varied widely, one trial (PMID 12356785) combined glucomannan with chitosan so its effect cannot be isolated, and no study measured heart attacks or other hard outcomes. Bloating is common, and tablet forms carry a rare choking or esophageal-obstruction risk, so take it with plenty of water and separate from oral medications.
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 = 0.685
- 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 + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status