Legacy AI grade · Sources dated 2026-06-01. Not expert reviewed. Coverage is limited to the listed sources. About the new summary workflow
Diindolylmethane (DIM) for Cancer Prevention
There is only weak evidence that diindolylmethane (DIM) supplements help prevent cancer. The mechanism is plausible and DIM shifts estrogen-metabolism markers, but the largest, highest-quality trial showed no real benefit, and no study has measured actual cancer outcomes.
Why this grade7-layer evidence engine
The grade is Weak because all four randomized trials relied on surrogate or biomarker endpoints rather than cancer incidence or mortality, and no Phase 3 trial exists. The decisive signal is negative: the largest, high-quality RCT of oral BR-DIM (PMID 22075942, n=551) found no significant effect on cervical CIN2+ (8.8% vs 12.4%, RR 0.7, p=0.198), undercutting any optimistic read.
Supportive findings are thin and indirect. A small CIN trial (PMID 26693258, n=78) showed regression, but used a vaginal suppository rather than an oral supplement. Biomarker trials in breast (PMID 28560655, n=130) and prostate (PMID 26313229, n=45) confirmed DIM raises the 2/16α-hydroxyestrone ratio and SHBG, yet measured no clinical cancer outcome, and prostate-tissue uptake was inconsistent.
Authorities reinforce caution. The FDA treats BR-DIM as investigational, and the EU has not authorized DIM as a supplement. Mayo Clinic, Harvard, and the American Cancer Society do not recommend supplements for cancer prevention; guideline chemoprevention is limited to drugs like tamoxifen. Cleveland Clinic's positive language applies to DIM in whole cruciferous vegetables, not to pills.
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 = 0.513
- 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 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status