Stroke (vegan-specific risk)

In the UK EPIC-Oxford cohort, vegetarians (including vegans) had higher rates of total and haemorrhagic stroke than meat eaters, but a meta-analysis of prospective cohorts found no clear overall association between vegetarian diets and stroke, and Taiwanese cohorts found lower stroke risk in vegetarians. Vegan-specific estimates rest on few cases and are imprecise. Proposed explanations, such as low vitamin B12 with raised homocysteine or low LDL cholesterol, remain untested hypotheses. No claim reaches moderate certainty because all of the evidence is observational, the cohorts disagree with one another, and the vegan subgroups are small.

Longevity
Vegan

Evidence retrieved up to 15 October 2026

What the research shows

Researchers have proposed, without establishing it, that low LDL cholesterol, low vitamin B12 status with raised homocysteine, or low animal protein intake might explain the higher haemorrhagic stroke rate seen in some vegetarian cohorts; in Taiwanese cohorts vegetarians had lower serum B12 and higher homocysteine, and B12 intake appeared to modify the diet-stroke association.

Very low certainty

This is uncertain; treat it as a lead, not a finding.

Take care: see the safety noteUnclear

Who this is about

adults following vegetarian or vegan diets

Practical note

Graded very-low: the B12 interaction came from an exploratory analysis with a p for interaction of 0.046, and the other mechanisms are offered by the cohort investigators as hypotheses for further research.

Vegan note

Vegans not using B12 supplements or fortified foods have the lowest B12 status, see the vitamin B12 topic, which is why this hypothesis is most relevant to them.

Safety note

These are untested explanations; none of these sources tested whether changing B12 status alters stroke rates in vegetarians or vegans.

Sources

Supports “The cause of the higher risk of haemorrhagic stroke in vegetarians is not known, but it might be explained by the low LDL cholesterol which has been associated with an increased risk in observational studies, Mendelian randomization analyses and in lipid lowering trials using statins” (Cardiovascular disease section) Key TJ, Papier K, Tong TYN. 2022. Proceedings of the Nutrition Society. Plant-based diets and long-term health: findings from the EPIC-Oxford study. publisher copyright, author manuscript in PMC; metadata and short quotes only
Supports “Our explorative analysis showed that vitamin B12 intake may modify the association between vegetarian diet and overall stroke (p interaction = 0.046).” (Abstract, results) Chiu THT, Chang HR, Wang LY, Chang CC, Lin MN, Lin CL. 2020. Neurology. Vegetarian diet and incidence of total, ischemic, and hemorrhagic stroke in 2 cohorts in Taiwan. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine
Context “it might also be related to other factors such as high homocysteine due to low vitamin B12, or possibly related to the low intake of animal protein, but further research is needed to examine these hypotheses.” (Cardiovascular disease section) Key TJ, Papier K, Tong TYN. 2022. Proceedings of the Nutrition Society. Plant-based diets and long-term health: findings from the EPIC-Oxford study. publisher copyright, author manuscript in PMC; metadata and short quotes only
Context “Vegetarians had lower serum vitamin B12 and higher folate and homocysteine than nonvegetarians.” (Abstract, results) Chiu THT, Chang HR, Wang LY, Chang CC, Lin MN, Lin CL. 2020. Neurology. Vegetarian diet and incidence of total, ischemic, and hemorrhagic stroke in 2 cohorts in Taiwan. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine

In a large UK cohort followed for 18 years, adults following vegetarian diets, vegans included, had higher rates of total and haemorrhagic stroke than meat eaters, about three more cases of total stroke per 1000 people over 10 years, alongside lower rates of ischaemic heart disease.

Low certainty

Further research is likely to change this.

Take care: see the safety noteRisk

Who this is about

UK adults following vegetarian diets, including vegans

Practical note

Graded low: a single prospective cohort of 48,188 participants with 1072 stroke cases and a hazard ratio of 1.20 for total stroke, adjusted for confounders; not upgraded because the result has not been replicated and Taiwanese cohorts point the other way.

Vegan note

Vegans were grouped with vegetarians in the main analysis, so this finding is only indirectly about vegans.

Safety note

This is an association from one observational cohort, not a demonstrated effect of the diet; the same cohort found lower ischaemic heart disease rates in the same group.

Sources

Supports “Vegetarians in the EPIC-Oxford study have a relatively low risk of ischaemic heart disease, diabetes, diverticular disease, kidney stones, cataracts and possibly some cancers, but a relatively high risk of stroke (principally haemorrhagic stroke) and bone fractures, in comparison with meat-eaters.” (Abstract) Key TJ, Papier K, Tong TYN. 2022. Proceedings of the Nutrition Society. Plant-based diets and long-term health: findings from the EPIC-Oxford study. publisher copyright, author manuscript in PMC; metadata and short quotes only
Supports “By contrast, vegetarians had 20% higher rates of total stroke (hazard ratio 1.20, 95% confidence interval 1.02 to 1.40) than meat eaters, equivalent to three more cases of total stroke (95% confidence interval 0.8 to 5.4 more) per 1000 population over 10 years, mostly due to a higher rate of haemorrhagic stroke.” (Abstract, results) Tong TYN, Appleby PN, Bradbury KE, Perez-Cornago A, Travis RC, Clarke R, Key TJ. 2019. BMJ. 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. CC BY 4.0; credit Tong et al., BMJ 2019

Evidence on stroke specifically in adults following a vegan diet is sparse and imprecise: a UK cohort found a higher but not statistically significant estimate for vegans, and a meta-analysis of five studies found no clear association between vegan diets and total stroke.

Very low certainty

This is uncertain; treat it as a lead, not a finding.

No known concerns at usual amountsUnclear

Who this is about

adults following a vegan diet

Practical note

Graded very-low: observational evidence with serious imprecision, a UK vegan hazard ratio of 1.35 with 95% CI 0.95 to 1.92 and a pooled vegan RR of 1.17 with 95% CI 0.69 to 1.99, and risk of bias rated moderate to serious by the meta-analysis authors, who judged the vegan stroke evidence limited-no conclusion.

Vegan note

This is the only directly vegan-specific evidence; most stroke findings come from vegetarians and vegans combined.

Sources

Supports “No clear association was observed between vegan diets and CVD or stroke; however, the number of studies was limited.” (Discussion) Dybvik JS, Svendsen M, Aune D. 2023. European Journal of Nutrition. Vegetarian and vegan diets and the risk of cardiovascular disease, ischemic heart disease and stroke: a systematic review and meta-analysis of prospective cohort studies. CC BY 4.0; credit Dybvik et al., European Journal of Nutrition 2023
Supports “When we assessed vegetarians and vegans separately, the point estimates for vegans were lower for ischaemic heart disease (0.82, 0.64 to 1.05) and higher for total stroke (1.35, 0.95 to 1.92) than meat eaters, but neither estimate was statistically significant” (Results) Tong TYN, Appleby PN, Bradbury KE, Perez-Cornago A, Travis RC, Clarke R, Key TJ. 2019. BMJ. 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. CC BY 4.0; credit Tong et al., BMJ 2019
Context “We considered the evidence on vegan diets and reduced risk of IHD to be limited-suggestive, and for CVD and stroke to be limited-no conclusion.” (Results, strength of evidence) Dybvik JS, Svendsen M, Aune D. 2023. European Journal of Nutrition. Vegetarian and vegan diets and the risk of cardiovascular disease, ischemic heart disease and stroke: a systematic review and meta-analysis of prospective cohort studies. CC BY 4.0; credit Dybvik et al., European Journal of Nutrition 2023

Across prospective cohorts, adults following vegetarian diets showed no clear difference in total stroke risk compared with nonvegetarians, although individual cohorts disagree, with Taiwanese cohorts reporting lower stroke risk among vegetarians.

Low certainty

Further research is likely to change this.

No known concerns at usual amountsNo clear effect

Who this is about

adults following vegetarian diets

Practical note

Graded low: a 2023 meta-analysis of 12 cohort estimates, RR 0.90 with 95% CI 0.77 to 1.05, with substantial heterogeneity, I2 61%, and moderate-to-serious risk of bias. A 2026 meta-analysis of plant-based diet index scores, not vegan or vegetarian status, also found no significant association with stroke.

Vegan note

Pooled vegetarian estimates mix vegans with lacto-ovo vegetarians, so they are only indirectly about vegans.

Sources

Supports “Vegetarian diets are associated with reduced risk of CVD and IHD, but not stroke, but further studies are needed on stroke.” (Abstract, conclusions) Dybvik JS, Svendsen M, Aune D. 2023. European Journal of Nutrition. Vegetarian and vegan diets and the risk of cardiovascular disease, ischemic heart disease and stroke: a systematic review and meta-analysis of prospective cohort studies. CC BY 4.0; credit Dybvik et al., European Journal of Nutrition 2023
Opposes “Taiwanese vegetarian diet is associated with a lower risk of ischemic and hemorrhagic strokes.” (Abstract, conclusion) Chiu THT, Chang HR, Wang LY, Chang CC, Lin MN, Lin CL. 2020. Neurology. Vegetarian diet and incidence of total, ischemic, and hemorrhagic stroke in 2 cohorts in Taiwan. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine
Context “We found no significant association with stroke risk.” (Abstract, results) Kim Y, Kim Y. 2026. Nutrients. A Plant-Based Diet and Cardiovascular Disease, Coronary Heart Disease, and Stroke: A Systematic Review and Meta-Analysis of Prospective Cohort Studies. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine