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Zinc
Supplements · Moderate evidence
Evidence
60
Impact
40
Zinc has real, modest evidence for shortening cold duration, preventing age-related macular degeneration, and supporting metabolic markers.
- Studies
- 10
- RCTs
- 1
- Meta-analyses
- 7
Research summary
- An updated Cochrane review found zinc can reduce the duration of common cold symptoms when started within 24 hours of onset, a finding consistent with an earlier Cochrane review and supportive systematic reviews, though the benefit is modest and dosing/formulation dependent.
- In eye health, the landmark AREDS randomized trial found high-dose zinc combined with antioxidant vitamins reduced progression to advanced age-related macular degeneration in at-risk patients — one of the more definitive supplement trials in ophthalmology.
- For metabolic health, multiple meta-analyses find zinc supplementation modestly improves lipid profiles and glycemic control in people with type 2 diabetes, with one study triangulating evidence from both a randomized trial and Mendelian randomization to support a causal glycemic benefit.
- As with several supplements here, zinc's effects are real but specific and modest rather than broadly protective.
Metabolic HealthImmune Function
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