Lutein for Cognitive Function
Lutein (almost always combined with zeaxanthin) shows only weak, preliminary signals for cognition in older adults: a few small trials report gains in narrow domains, but the pooled meta-analysis found no significant overall effect, so it is not an established cognitive aid.
Why this grade7-layer evidence engine
The grade reflects small, inconsistent human data. Four short-to-medium-term RCTs (n approximately 44 to 90) reported domain-specific gains: complex attention and cognitive flexibility (PMID 28824416), buffered verbal-learning decline with increased prefrontal activation on fMRI (PMID 28695791, Cohen's d 0.84), and improved visual episodic memory and visual learning (PMID 35252311). However, a 2021 meta-analysis of RCTs (PMID 34641336) found no statistically significant overall cognitive effect, and a 52-week brain-morphology trial (PMID 31871787) showed negligible between-group differences.
Several caveats prevent a higher grade. The trials are small and short, lutein was co-administered with zeaxanthin so its effect cannot be isolated, and two studies (PMID 35252311, PMID 31871787) carry industry conflicts of interest, raising the risk of optimistic reporting.
Regulators and clinicians do not endorse this use. The US FDA accepts lutein only as a safe food ingredient (GRAS) and previously rejected eye-health claims; the UK NHS advises prescribers not to initiate lutein-and-antioxidant products; WHO addresses only additive safety (ADI 'not specified'); and clinical bodies (Cleveland Clinic, plus the Alzheimer's Association and American Academy of Neurology) remain cautious, holding that no supplement is proven to benefit cognition.
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 = 0.588
- 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