[Home](/) What we know Heart disease and stroke [How do plant-based and animal-based diets compare for health?](/what-we-know/health-comparisons/) [1What a comparison like this can show](/what-we-know/health-comparisons/what-a-comparison-can-show/) [2Why a mechanism is not an answer](/what-we-know/health-comparisons/why-a-mechanism-is-not-an-answer/) [3Protein: how much, and from where](/what-we-know/health-comparisons/protein/) [4Calcium and bone: the milk question](/what-we-know/health-comparisons/calcium-and-bone/) [5Fats: which one replaces which](/what-we-know/health-comparisons/fats/) 6Heart disease and stroke [7Death from any cause](/what-we-know/health-comparisons/death-from-any-cause/) [8The reference diet, and what it projects](/what-we-know/health-comparisons/the-reference-diet-and-what-it-projects/) What we know · Part 6 of 8 # Heart disease and stroke Entry checked 20 September 2026 · 9 sentences, each with its source · no person approved these sentences · [the entry's full limits](/what-we-know/health-comparisons/#limits) This is where the comparison produces its clearest result, and also its clearest warning, because the two outcomes move in opposite directions in the same group of people. Start with the cohort that split plant-based eating three ways, because that split is the single most useful correction in the whole literature. Over 4,833,042 person-years in three United States cohorts, with 8,631 incident cases of coronary heart disease, a diet index that gave positive scores to healthy plant foods was associated with a hazard ratio of 0.75 (95% confidence interval 0.68 to 0.83), while an index that gave positive scores to less healthy plant foods was associated with 1.32 (1.20 to 1.46), and the overall plant-based index was not clearly associated with coronary heart disease (0.92, 0.83 to 1.01). [[1]](#source-1) [[1]](#source-1) Then the British cohort, which is the one usually quoted for the benefits. In EPIC-Oxford, over 18.1 years and 48,188 participants, fish eaters had 13% lower rates of ischaemic heart disease than meat eaters (hazard ratio 0.87, 95% confidence interval 0.77 to 0.99) and vegetarians 22% lower (0.78, 0.70 to 0.87), equivalent to 10 fewer cases of ischaemic heart disease per 1000 people over 10 years. [[2]](#source-2) [[2]](#source-2) In the same cohort, the ischaemic heart disease associations were partly attenuated after adjustment for self-reported high cholesterol, high blood pressure, diabetes and body mass index, to a hazard ratio of 0.90 (95% confidence interval 0.81 to 1.00) in vegetarians with all adjustments. [[2]](#source-2) The same cohort, the same follow-up, the same people — and the other direction. The same cohort found the opposite signal for stroke: vegetarians had 20% higher rates of total stroke than meat eaters (hazard ratio 1.20, 95% confidence interval 1.02 to 1.40), equivalent to three more cases per 1000 people over 10 years, mostly haemorrhagic stroke, and this association did not attenuate after further adjustment for disease risk factors. [[2]](#source-2) [[2]](#source-2) The pooled cohort evidence agrees with the first half of that and not the second. A meta-analysis of prospective cohort studies found vegetarians had a lower risk of incidence or mortality from ischaemic heart disease (relative risk 0.75, 95% confidence interval 0.68 to 0.82) and a lower incidence of total cancer (0.92, 0.87 to 0.98), but no significant association with total cardiovascular and cerebrovascular disease, all-cause mortality or cancer mortality. [[3]](#source-3) Two more recent syntheses are worth having beside it, one because of who wrote it and what diet it actually tested, and one because of how carefully it states its own limits. In the UK Biobank, 192,274 participants without cardiovascular disease at baseline were followed for a median of 12.3 years, and those in the top quartile of a heart-protective predominantly plant-based diet score had a lower risk of overall cardiovascular disease (hazard ratio 0.92, 95% confidence interval 0.88 to 0.95) than those in the bottom quartile. [[4]](#source-4) The diet score in that study included fish, eggs and low-fat dairy alongside plant foods, and the authors call for research in more diverse populations to test whether the finding reproduces. [[4]](#source-4) [[4]](#source-4) An umbrella review of meta-analyses reported a 29% lower risk of cardiovascular disease incidence and a 24.1% lower risk of ischaemic heart disease incidence with vegetarian diets, but with high heterogeneity, and its authors state that evidence quality and consistency vary. [[5]](#source-5) [[5]](#source-5) One further finding belongs in this section even though it is not about plants or animals, because it is the largest single effect on this page and it is about processing rather than about origin. An umbrella review of 45 pooled analyses and 9,888,373 participants found direct associations between ultra-processed food exposure and 32 of 45 health parameters, including a risk ratio of 1.50 (95% confidence interval 1.37 to 1.63) for cardiovascular disease mortality, which its own authors graded as very low quality evidence. [[6]](#source-6) [[6]](#source-6) ## What this section does not show One cohort, two directions The heart-disease benefit and the stroke signal come from the same people over the same follow-up. Reporting either without the other is what this section exists to avoid. The adjustment changed the answer The ischaemic heart disease association fell from 0.78 to 0.90 once self-reported cholesterol, blood pressure, diabetes and body mass index were accounted for. Both numbers are printed. Cohorts, not trials No trial has assigned anyone to a vegetarian or an omnivorous diet and followed a heart attack. Every result here is an association in people who chose their own diets. The synthesis says so itself The largest review on this page reports that its evidence quality and consistency vary, and calls for more research. That is its authors' assessment, not ours. All twelve elements The entry's full limits block covers the dates, the study designs, who was and was not studied, the comparators, the adjustment sets, the uncertainty, the counter-signals and what we did not check. [Read it on the entry's first page.](/what-we-know/health-comparisons/#limits) This page is general information about published research. It is not medical advice, and it is not a substitute for advice from a qualified health professional. No clinician-patient relationship exists, and we do not know your diet, your medications, your test results, your medical conditions or your history. Talk to a health professional before changing your diet if you are pregnant or breastfeeding, feeding an infant or child, over 65, taking medication, living with a medical condition, or if you have been diagnosed with a nutrient deficiency or have a history of disordered eating. The evidence described is about groups and diets, not about you, and not about any product listed on this site. If you are unwell, contact a health professional; in an emergency, call 911. No clinician reviewed this entry. It is a compilation of published sources by this site. [PreviousFats: which one replaces which](/what-we-know/health-comparisons/fats/) [NextDeath from any cause](/what-we-know/health-comparisons/death-from-any-cause/) ## Sources for this section Every numbered sentence above was checked against the source with that number on the date shown. The number links to the entry in this list, and the entry's first page lists every source it cites. Healthful and Unhealthful Plant-Based Diets and the Risk of Coronary Heart Disease in U.S. Adults. Journal of the American College of Cardiology. prospective cohort study. [Open the source ↗](https://doi.org/10.1016/j.jacc.2017.05.047) Checked 19 September 2026. Backs 1 sentence in this section. Risks of ischaemic heart disease and stroke in meat eaters, fish eaters, and vegetarians over 18 years of follow-up: results from the prospective EPIC-Oxford study. The BMJ. prospective cohort study. [Open the source ↗](https://doi.org/10.1136/bmj.l4897) Checked 19 September 2026. Backs 3 sentences in this section. Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Critical Reviews in Food Science and Nutrition. systematic review with meta-analysis. [Open the source ↗](https://doi.org/10.1080/10408398.2016.1138447) Checked 19 September 2026. Backs 1 sentence in this section. Association of Healthy Predominantly Plant-Based Diet with Reduced Cardiovascular Disease Incidence and Mortality and Development of Novel Heart-Protective Diet Index. Nutrients. systematic review and meta-analysis. [Open the source ↗](https://doi.org/10.3390/nu17162675) Checked 19 September 2026. Backs 2 sentences in this section. Association of Vegetarian and Vegan Diets with Cardiovascular Health: An Umbrella Review of Meta-Analysis of Observational Studies and Randomized Trials. Nutrients. umbrella review. [Open the source ↗](https://doi.org/10.3390/nu15194103) Checked 19 September 2026. Backs 1 sentence in this section. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. The BMJ. umbrella review. [Open the source ↗](https://doi.org/10.1136/bmj-2023-077310) Checked 19 September 2026. Backs 1 sentence in this section. How this was written ## Method and care Every factual sentence here was checked against a retrieved copy of the source it names: one sentence, one retrieved source, one verbatim quote, one checked date. No person reviewed or approved these sentences before publication. The journal sources were retrieved as their Europe PMC records, which is the quotable text that registry serves; the EAT-Lancet material was retrieved as the text of the Commission's own summary report. The entry records, for each source, what was retrieved and what was not. Reviewed by: — no named reviewer has reviewed this entry, and no clinician has. It is a compilation of published sources by this site. Written by: Find My Next Bite's writing session, 20 September 2026, working from sources retrieved the same day. No person reviewed or approved these sentences before publication, and no clinician has read them. Funding: this section is unfunded. It takes no sponsorship, and the rule we adopted in advance says no funder may ever be a company whose products the entries or the directory describe. Corrections: if a source here has changed, moved or been retracted, tell us and we will suspend the sentence and record the change. 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