Heart

Vegans have the lowest risk of heart disease

By WhyStopHarmingAnimals.com

Of all the diets researchers have compared, vegan and vegetarian ones sit at the bottom of the heart-disease risk curve. The finding comes from long-running cohorts[6][7], from pooled analyses of dozens of studies[1][2][3], and from randomized trials that measure the blood fats[9][10][11] that drive the disease. The one place the evidence pushes back is stroke[6], and that result is set out below.

What the large studies found

The widest view comes from a 2023 umbrella review in Nutrients, which pooled the meta-analyses of both cohorts and trials[1]. Vegetarian and vegan diets came with 29% less cardiovascular disease[1], 32% less death from ischemic heart disease[1] and 33% less ischemic stroke[1]. The authors flag that the quality and consistency of the evidence vary from one outcome to the next[1].

A 2020 umbrella review in Clinical Nutrition covered twenty meta-analyses and 34 health outcomes. Vegetarian diets came with total cholesterol 0.55 mmol/L lower[2] and LDL 0.47 mmol/L lower[2] than omnivorous diets, along with lower risk of ischaemic heart disease, diabetes and cancer[2]. The same review found worse one-carbon metabolism, which is why vegans supplement B12[2].

Pooled analyses in the European Journal of Nutrition place vegan and vegetarian patterns at lower risk of cardiovascular disease[3], ischemic heart disease and stroke[3]. Two reviews of the cardiometabolic evidence land in the same place: next to mixed diets, vegan and vegetarian diets come with less ischemic heart disease[4], and plant-exclusive diets show the most favorable blood lipids, blood pressure and body fat[5].

The largest single cohort is EPIC-Oxford, which followed 48,188 people[6] in Britain for 18 years. Vegetarians and vegans had 22% less ischaemic heart disease than meat eaters[6], or 10 fewer cases per 1,000 people over a decade[6].

A common objection is that people who skip meat are healthier in other ways, so the diet gets credit it hasn’t earned. Seventh-day Adventists make a useful test, because as a group they already avoid many other risk behaviors. Within that health-conscious population, the Adventist Health Study found that those who ate no meat still had lower death rates from ischemic heart disease[7].

The pattern shows up outside Western countries too. In the Indian Migration Study, vegetarians had lower total cholesterol, triglycerides, LDL cholesterol and diastolic blood pressure than non-vegetarians[8], although rates of diabetes and hypertension did not differ between the groups[8].

Thirty randomized trials on cholesterol

Cohorts can only show that diet and disease travel together. Trials assign people to a diet and measure what changes. A 2023 meta-analysis in the European Heart Journal pooled 30 randomized trials that compared plant-based with omnivorous diets[9]. The plant-based diets lowered total cholesterol by 0.34 mmol/L[9], LDL by 0.30 mmol/L[9] and apolipoprotein B by 12.9 mg/dL[9]. Triglycerides did not move[9]. The size of the effect held across age, continent, trial length and health status[9].

LDL and apolipoprotein B are the measures that track the particles building plaque in artery walls, which is why these numbers matter more than any single cohort. An earlier pooling of eleven trials, published in the Journal of the American Heart Association in 2015, found that vegetarian diets lowered total, LDL, HDL and non-HDL cholesterol, again with no change in triglycerides[10]. A 2017 analysis in Nutrition Reviews, combining observational studies with controlled trials of four weeks or longer, found lower total, LDL and HDL cholesterol on vegetarian and vegan diets than on the comparison diets[11].

The effect holds outside a metabolic ward. In the BROAD study, a randomized trial run in the community, people with obesity, ischaemic heart disease or type 2 diabetes ate a whole-food plant-based diet without counting calories[12]. After six months they had lost about 12 kg, their BMI and cholesterol had improved and their HbA1c had fallen[12]. Two people with diabetes no longer met the diagnostic cut-off[12].

Fat is a large part of the mechanism. In a 2017 presidential advisory, the American Heart Association reported that trials which cut saturated fat and replaced it with polyunsaturated vegetable oil reduced cardiovascular disease by about 30%, close to what statin treatment achieves[13].

What replaces the meat matters as well. A 2019 meta-analysis of 36 trials in Circulation found that red meat looked no different from the comparison diets when they were all pooled together[14]. Split by the replacement, swapping red meat for high-quality plant protein lowered total cholesterol and LDL[14], while swapping it for fish or refined carbohydrate did not[14]. The gain comes from eating plant protein in place of meat, and a plate of refined starch does not deliver it[14].

Eggs and chicken are no refuge

People who cut back on red meat often lean harder on eggs and chicken, and the evidence gives them little cover. A meta-analysis found a dose-response link between egg intake and both cardiovascular disease and diabetes[15]. A 2019 JAMA study pooled six US cohorts, 29,615 people followed for a median 17.5 years, and found that each extra half egg a day came with 6% more cardiovascular disease[16] and 8% more death from any cause[16]. The egg link ran through dietary cholesterol[16].

A 2022 cohort study with an updated meta-analysis, published in Circulation and covering 22,035 deaths, found that each extra 300 mg of dietary cholesterol a day came with 10% higher all-cause mortality and 13% higher cardiovascular mortality[17]. Each extra 50 g of egg a day, about one egg, came with 6% and 9%[17]. The randomized trials fit: eating more eggs raised LDL cholesterol by about 8 mg/dL and worsened the LDL-to-HDL ratio, with larger effects in trials that ran past two months[18].

Poultry was counted in the same six US cohorts, 29,682 adults followed for a median 19 years[19]. Each additional two servings a week came with 7% more cardiovascular disease for processed meat[19], 3% for unprocessed red meat[19] and 4% for poultry[19]. Fish showed nothing either way[19], and only the red meats tracked with dying sooner[19]. The authors call the increases small[19], and because the analysis draws on the same cohorts as the 2019 egg study, the two are not independent replications[19].

The stroke result from EPIC-Oxford

The same EPIC-Oxford cohort that found 22% less ischaemic heart disease also found 20% more total stroke among vegetarians and vegans[6], mostly haemorrhagic: 3 more cases per 1,000 people over a decade[6], set against 10 fewer cases of heart disease[6]. The authors could not rule out lower B12 or lower cholesterol behind it, and almost everyone in the cohort was white British. Other pooled evidence leans the other way on stroke[1][3], including the 33% less ischemic stroke in the 2023 umbrella review[1], but the EPIC-Oxford number stands as a real finding[6].

Most of the evidence on heart disease outcomes is observational, and cohorts can never fully separate a diet from the people who choose it. The trials on LDL and apolipoprotein B don’t share that weakness, and they point the same way as the cohorts: less animal food, less of the cholesterol that clogs arteries[9][10][11], and less heart disease[1][6].