Cranberry for Cardiovascular Disease
Cranberry is not a proven treatment for cardiovascular disease. The largest meta-analysis found no effect on blood pressure, and the only positive signals come from small trials measuring surrogate markers rather than real heart outcomes.
Why this grade7-layer evidence engine
The grade is held low because the strongest evidence is null. The largest and most recent meta-analysis (PMID 37963472, 17 RCTs) found no significant change in blood pressure (systolic -0.81 mmHg, diastolic -0.15 mmHg), with only 2 of 17 trials positive. An earlier meta-analysis (PMID 31023488) saw at most a modest systolic dip, no lipid improvement, and noted that juice formulations may even raise triglycerides.
The positive findings come almost entirely from small, short trials of surrogate markers. Cranberry improved flow-mediated dilation in healthy adults (PMID 35322843, n=45) and acutely in a 10-person dose-response study (PMID 27242317), and one trial in coronary patients lowered arterial stiffness by about 0.5 m/s (PMID 21411615, n=44). An industry-funded trial in people with elevated blood pressure (PMID 34444779, Ocean Spray) missed its primary endpoint. No trial has tested heart attacks, stroke, or mortality.
Regulators and clinicians do not endorse cranberry for the heart. The FDA calls the overall evidence 'limited and inconsistent' and only for urinary-tract infections, EFSA rejected a cardiovascular claim, and the WHO offers only a reference monograph. Mayo Clinic, Harvard, and the AHA/ACC do not address it. The NHS adds a safety caveat that matters here: people on warfarin, common among heart patients, should avoid cranberry products.
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 = 0.485
- 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 + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status