EvidenceHealthSupplementsVitamins
Antioxidant Supplements & Mortality
- Study type:
- Cochrane systematic review and meta‑analysis of randomised trials
- Topic:
- Vitamin/antioxidant supplements and overall survival
- Added:
- 2025-11-25
- Status:
- published
Strength of evidence
Low – large secondary synthesis with many RCTs, but endpoints and trial quality are heterogeneous; supplements are often tested on soft or mixed outcomes.
Source
Bjelakovic G, et al. Antioxidant supplements for prevention of mortality. Cochrane Database Syst Rev. 2012;(3):CD007176.
Open original studyThis Cochrane review pooled data from dozens of randomised trials where people took antioxidant vitamin supplements (A, C, E, beta‑carotene, selenium) and compared them with placebo or no pills. Across all studies, antioxidant supplements did not reduce overall mortality; in some analyses they were even linked to a slight increase in death risk. The review strongly challenges the marketing claim that "antioxidant pills make you live longer", but the included trials vary in quality and were not all designed as pure mortality studies.
Key findings
- Included more than 200,000 participants from many randomised trials of antioxidant supplements vs placebo/no supplement.
- Main supplements: vitamin A, beta‑carotene, vitamin C, vitamin E and selenium, alone or in combinations.
- Overall, no reduction in all‑cause mortality was seen with antioxidant supplements.
- Some antioxidant regimens (especially beta‑carotene and vitamin A in certain groups) were associated with increased mortality.
- Trials often targeted prevention in generally healthy or at‑risk adults, not just severely ill patients.
- Evidence does not support routine antioxidant supplementation for longevity in the general population.
Background
- For years, antioxidant vitamins have been sold with the promise of neutralising "free radicals" and preventing chronic diseases and early death. Bjelakovic and colleagues asked: Do antioxidant supplements (taken as pills) reduce overall mortality in adults compared with placebo or no supplementation?
Methods
- Study type: Cochrane systematic review and meta‑analysis. Inclusion criteria: Randomised or quasi‑randomised controlled trials, adult participants, comparison of antioxidant supplements vs placebo or no intervention, reporting of all‑cause mortality. Interventions: Vitamin A, beta‑carotene, vitamin C, vitamin E, selenium, alone or in combination. Endpoints: All‑cause mortality (hard endpoint), sometimes disease‑specific outcomes as secondary measures. Trials differed widely in dosage, duration, baseline health status and co‑interventions.
Results
- Across all included trials: No evidence that antioxidant supplements reduced all‑cause mortality. Some specific regimens (especially those including beta‑carotene or vitamin A) were associated with a small but statistically significant increase in mortality. These findings contradict the idea that adding antioxidant pills on top of usual diets is beneficial for longevity.
Interpretation
- From a WorthDay perspective, S15 is important because it focuses on a hard endpoint (death), it pools many randomised comparisons, and it finds no benefit and possible harm. However: It is a review, not a single, meticulously controlled trial that fully meets WorthDay high‑evidence criteria. The underlying studies vary in design, populations and supplement doses. Therefore, S15 is rated as 🟠 low evidence in the WorthDay system – but still powerful enough to seriously question casual antioxidant supplementation.
Limitations
- Heterogeneous populations (healthy, at‑risk, specific patient groups).
- Supplement doses and combinations vary widely.
- Some trials were not primarily designed as mortality studies.
- Publication bias and selective reporting cannot be fully excluded.
- Pooled analysis may obscure subgroup differences, although no clear beneficial subgroup was identified.
WorthDay perspective
- S15 helps WorthDay say, with data: "Large randomised evidence does not support the idea that antioxidant vitamin pills extend life. In some cases, they may even do harm."
- This supports WorthDay's focus on whole foods and dietary patterns rather than isolated pills, scepticism toward heavily marketed supplement regimes.
- In Health challenges and Food Nerds content, you can pair S15 with studies on whole foods (e.g. raw milk, meat, honey) to show improvements in health come from real food contexts, not necessarily from extracting and concentrating single molecules.
Permalink: https://www.worth-day.com/science-compass/s0015-antioxidant-supplements-mortality
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