Longevity & Aging · Diets
vegetarian diet decreases all-cause mortality
In plain terms: Do vegetarian, plant-forward diets help you live longer?
Part of: • Aging
Unclear. Some large studies link vegetarian and plant-based eating to longer life, but others find no difference, and where a benefit shows up it tracks overall diet quality. All of the evidence is observational.
📅 Last reviewed: 2026-07-15 ⓘ
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
What the evidence shows
Contested. Vegetarian/plant-forward patterns associate with lower all-cause mortality in the Adventist Health Study-2 (HR ~0.88) and in pooled plant-based-diet-index cohorts (HR 0.90, I2=91%), but EPIC-Oxford, the Jackson Heart Study and PLCO find no difference, and the Dinu 2017 meta-analysis found lower ischemic heart disease but not lower all-cause mortality.
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Etesami E, Nikparast A, Rahmani J, Rezaei M, Ghanavati M 2025 · Food Funct | observational | mixed | moderate | 2025 dose-resp: HEALTHY-PDI inverse, UNHEALTHY-PDI harmful; quality-dependent not vegetarian-per-se |
| Blackie K, Bobe G, Takata Y 2023 · J Health Popul Nutr | observational | contradicts | moderate | PLCO n=117673 small vegetarian n self-report; weak single-cohort |
| Appleby PN, Crowe FL, Bradbury KE, Travis RC, Key TJ 2016 · Am J Clin Nutr | observational | contradicts | moderate | EPIC-Oxford: vegetarians vs comparable non-vegetarians had no significant all-cause mortality difference |
| Schaefer E, Barbaresko J, Roden M, Kuss O, Schlesinger S 2025 · Diabetes Care | observational | supports | moderate | UK Biobank diabetics: higher healthy-PDI adherence associated with lower all-cause mortality |
| Mo Q, Wu J, Lu Y, Zhang X 2025 · Frontiers in Nutrition | meta-analysis | supports | moderate | Meta-analysis of prospective studies found healthful plant-based diet indices associated with lower total and cause-specific mortality. |
| Tharrey M, Mariotti F, Mashchak A, Barbillon P, Delattre M, Fraser GE 2018 · Int J Epidemiol | observational | supports | moderate | AHS-2: plant-protein patterns lower CV mortality vs animal-protein |
| Zhou L, Zhang R, Yang H, Zhang S, Zhang Y, Li H, Chen Y, Maimaitiyiming M, Lin J, Ma Y, Wang Y, Zhou X, Liu T, Yang Q, Wang Y 2024 · European J Nutrition | observational | mixed | moderate | Healthful PDI linked to lower mortality, but unhealthful plant-based patterns raised risk; association attenuated across socioeconomic strata. |
| Weston LJ, Kim H, Talegawkar SA, Tucker KL, Correa A, Rebholz CM 2022 · PLoS Medicine | observational | contradicts | moderate | Jackson Heart Study, n=3,635 African American adults, 597 deaths over median 15y: NO association of plant-based diet score with all-cause mortality - overall PDI HR 0.96 (0.78-1.18), hPDI 0.94 (0.76-1.16), uPDI 1.06 (0.86-1.30), highest vs lowest tertile; fully adjusted overall PDI 1.07 (0.87-1.33). CVD also null (PDI 1.06, 0.78-1.42). Authors: 'greater adherence to a plant-based diet was not associated with CVD or all-cause mortality'. Narrow exposure range - the top PDI tertile still ate 37 g/d animal protein and the index did not capture exclusive plant eaters. |
| Orlich MJ, Singh PN, Sabaté J, Jaceldo-Siegl K, Fan J, Knutsen S, Beeson WL, Fraser GE 2013 · JAMA Internal Medicine | observational | supports | high | AHS-2 cohort: vegetarian dietary patterns associated with lower all-cause mortality (HR~0.88) vs non-vegetarians, landmark prospective evidence. |
| Jafari S, Hezaveh E, Jalilpiran Y, Jayedi A, Wong A, Safaiyan A, Barzegar A 2022 · Crit Rev Food Sci Nutr | observational | supports | moderate | PBD MA n=508861 all-cause HR0.90, CHD 0.77; I2=91%; healthful-PBD drives benefit |
| Dinu M, Abbate R, Gensini GF, Casini A, Sofi F 2017 · Crit Rev Food Sci Nutr | meta-analysis | contradicts | high | Dinu 2017 SR/MA, 10 prospective cohorts (plus 86 cross-sectional): vegetarian diet showed 'a significant reduced risk of incidence and/or mortality from ischemic heart disease (RR 0.75; 95% CI, 0.68 to 0.82) ... but not of total cardiovascular and cerebrovascular diseases, all-cause mortality and mortality from cancer.' Null on the claim's object (all-cause mortality) = contradicts; IHD benefit is off-object. All-cause RR/CI not in abstract. [abstract-grade] |
| Abris GP, Shavlik DJ, Mathew RO, Butler FM, Oh J, Sirirat R, Sveen LE, Fraser GE 2024 · Am J Clin Nutr | observational | supports | moderate | AHS-2 cohort: vegetarians lower all-cause mortality (strongest in men) |
Disagree, or know a study we missed?
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.