Stroke

Stroke risk tracks diet quality more than the vegetarian label

By WhyStopHarmingAnimals.com

Stroke is the one cardiovascular outcome where the evidence on plant-based eating pulls in both directions[1][4][5]. The healthiest plant-based diets come with less stroke[1] and red meat comes with more[2], but being vegetarian has not, on its own, reliably lowered stroke risk[1][3], and one large British cohort found more of it[4].

Healthy plant diets and red meat

A 2021 study in Neurology followed 209,508 people for up to 32 years, during which 6,241 had a stroke[1]. People whose diets scored as the healthiest plant-based had 10% less total stroke[1]. Ischemic stroke was only marginally lower[1], and hemorrhagic stroke showed no consistent pattern[1]. The small number of vegetarians in the study showed no difference at all[1], so the benefit came from the quality of the diet[1].

Red meat runs the opposite way[2]. A 2016 meta-analysis in the Journal of Stroke and Cerebrovascular Diseases pooled seven cohorts covering 2,079,236 people and 21,730 strokes[2]. Total red meat came with 14% more stroke[2] and processed red meat with 17% more[2]. The extra risk appeared above about 50 g of red meat a day[2], and no type of meat was linked to hemorrhagic stroke[2].

Vegetarians as a group

A 2021 meta-analysis in Nutrients combined seven cohorts with 29,705 vegetarians and 627,728 non-vegetarians and found no significant difference in stroke (hazard ratio 0.86, confidence interval 0.67 to 1.11)[3]. Studies run in Asia did show lower risk[3].

EPIC-Oxford, reported in The BMJ in 2019, went further in the wrong direction. Among 48,188 people followed for 18 years, vegetarians and vegans had 22% less ischaemic heart disease[4] than meat eaters but 20% more total stroke, mostly haemorrhagic[4]. In absolute terms that is about 3 more strokes per 1,000 people over a decade[4], against 10 fewer cases of ischaemic heart disease[4]. The authors could not rule out lower B12 or lower cholesterol behind the extra strokes, and almost everyone in the cohort was white British, which limits how far the result can be applied.

The pooled evidence still leans the other way[5]. A 2023 umbrella review in Nutrients, combining the meta-analyses of cohorts and trials, reports 33% less ischemic stroke on vegetarian and vegan diets, while noting that the quality and consistency of the evidence vary between outcomes[5].

What the studies have in common

Every one of these studies is observational, so none settles cause. Read together, they say that stroke risk follows what people eat more than the label they eat under[1][3]. Whole plant foods come with less stroke[1], and red and processed meat come with more[2]. Lower B12 is one of the explanations EPIC-Oxford could not rule out, and it is the nutrient vegans are already advised to supplement.