Longevity & Aging · Metabolic & Cardiometabolic
dietary and anti-aging supplements do-not-improve hard health outcomes in well-nourished non-deficient people
In plain terms: If I eat well and have no deficiency, will supplements make me healthier?
Broadly supported for hard endpoints (mortality, CVD, cancer) where multivitamins and popular longevity supplements show null RCT results — but not absolute: at least one large RCT (COSMOS) found a modest multivitamin benefit on cognition.
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
How the studies fall
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Lippman 2009 · JAMA | RCT | supports | high | SELECT: selenium and/or vitamin E did not prevent prostate or other cancers in generally healthy men, supporting no-benefit. |
| Baker 2023 · Alzheimers Dement | RCT | mixed | moderate | COSMOS-Mind: multivitamin showed a modest cognitive benefit in older adults while cocoa extract did not, a partial exception on a soft outcome. |
| Tobias 2025 · Nat Commun | RCT | supports | high | VITAL-T2D: vitamin D supplementation did not reduce incident type 2 diabetes in a general older US population. |
| Yeung 2023 · Am J Clin Nutr | RCT | contradicts | moderate | COSMOS multivitamin RCT: modest improvement in memory/cognition in older adults without diagnosed deficiency — a genuine positive exception that narrows the absolute claim. |
| Alexander 2013 · J Am Coll Nutr | meta-analysis | supports | moderate | 12 cohorts plus 3 RCTs: multivitamin use not associated with reduced all-cause/CVD/cancer mortality in healthy adults — null for the outcomes that matter. |
| Park 2026 · Thromb Haemost | RCT | supports | moderate | COSMOS ancillary: neither cocoa extract nor multivitamin significantly reduced venous thromboembolism in older adults. |
| Ogata 2023 · Nutrients | RCT | supports | moderate | Reanalysis of VITAL using win-ratio composite outcomes found marine n-3 supplementation did not meaningfully reduce cardiovascular events in healthy older adults. |
| Li 2023 · Diabetes Care | RCT | supports | high | COSMOS: cocoa extract supplementation did not reduce incident type 2 diabetes in older adults, supporting no hard-outcome benefit. |
| Setayesh 2026 · Int J Obes | meta-analysis | mixed | moderate | Resveratrol RCT meta-analysis: inconsistent/inconclusive effects on anthropometrics and adipokines — no reliable outcome benefit, consistent with claim. |
| Gaziano 2012 · JAMA | RCT | contradicts | high | PHS II: daily multivitamin modestly but significantly reduced total cancer incidence in male physicians, a hard-outcome benefit that partly contradicts the no-benefit claim. |
| O'Connor 2022 · JAMA | meta-analysis | supports | high | USPSTF evidence review: insufficient/no benefit of vitamin-mineral supplements for preventing CVD or cancer in generally healthy, non-deficient adults; possible harm (beta-carotene) — strongly supports the claim for hard outcomes. |
| Neves 2026 · Cureus | meta-analysis | supports | moderate | Narrative synthesis concluded that in generally nourished adults multivitamins do not reduce cardiovascular events or mortality and cancer-prevention evidence is marginal. |
Disagree, or know a study we missed?
We grade by evidence, not opinions. The way to weigh in is to point us to a study we haven't cited (check the evidence table above first), or to flag a problem with one we have. Every submission is reviewed; if it holds up, the grade updates and shows in Science Changes Its Mind.
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.