Is a vegan diet healthy?

The objection

“Plant-based is a fad sold on celebrity hype. The studies behind it are observational, so they can’t separate the diet from the health-conscious people who choose it, and in Britain’s biggest studies vegetarians died at the same rate as comparable meat-eaters and had more strokes. A diet that only works with B12 supplements is hard to call healthy.”

The answer

A well-planned vegan diet can be healthy in the judgement of the British and US dietitians’ associations, and the large studies back that up for heart disease and type 2 diabetes, though the objection gets several things right: most of the evidence is observational, death rates were no lower in the British studies, and EPIC-Oxford’s higher stroke rate has to be taken seriously. Calling it a fad doesn’t fit the record, since tens of thousands of people in Britain and North America have been followed for up to 18 years and their results for heart disease and diabetes keep pointing the same way. The British Dietetic Association (BDA) says carefully planned plant-based diets, which it defines as having few or no ingredients from animals, “can support healthy living at every age and life stage” [1]. The US Academy of Nutrition and Dietetics said in 2025 that appropriately planned vegan diets can be nutritionally adequate for adults who are not pregnant or breastfeeding, and can offer long-term health benefits [2]. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) is more cautious about children: in 2025 it judged it inconclusive whether a strictly vegan diet supports normal growth, though the studies it reviewed found no difference in height or BMI from omnivorous children, and it called B12 supplements essential and advised regular checks on vegan children’s growth and nutrition [14]. In pregnancy and while breastfeeding, the NHS says, vegans need to make sure they get enough vitamins and minerals for their baby to develop healthily [15].

Do vegetarians and vegans get less heart disease?

Vegetarians, vegans included, have had about a fifth less ischaemic heart disease than meat-eaters in the large cohort studies, and the figure for vegans alone points the same way but is less certain. Vegans are a small minority even in the biggest studies, so most figures here are for vegetarians with vegans counted among them, and the figures for vegans alone say so. EPIC-Oxford (Tong et al., 2019) followed 48,188 British adults who had no heart disease or stroke at the start, 16,254 of them vegetarian or vegan, for 18 years [3]. After allowing for smoking, alcohol, exercise, education and other differences, the vegetarians had a 22% lower rate of ischaemic heart disease (hazard ratio 0.78, 95% CI 0.70 to 0.87) [3]. For someone of the cohort’s average age of 44.7, that works out at 10 fewer cases per 1,000 people over ten years, 36 against 46 [3]. The vegans’ own estimate was similar (0.82), but with few cases among them it was too uncertain to rule out no difference (0.64 to 1.05) [3].

A 2023 meta-analysis of 13 cohort studies with 844,175 participants (Dybvik et al.) found 21% less ischaemic heart disease in vegetarians (relative risk 0.79, 0.71 to 0.88) and 15% less cardiovascular disease overall (0.85, 0.79 to 0.92), and its authors judged both links probably causal under the World Cancer Research Fund’s criteria [4]. For vegans the heart disease estimate was 0.82 (0.68 to 1.00), on the edge of significance, and the authors rated the studies’ risk of bias as moderate to serious [4]. Whether a diet can reverse heart disease that is already there is a separate question.

What about diabetes, blood pressure and cancer?

Vegans in the Adventist Health Study-2 had less type 2 diabetes and lower blood pressure than Adventists who ate meat, and the latest pooled studies find less cancer overall in vegetarians and vegans, though the largest study found two cancers more common in them. The study recruited Seventh-day Adventist church members across the US and Canada. Few of them smoke or drink, which makes those habits unlikely to explain the differences, but its researchers cautioned against generalising the results to people whose reasons for eating this way may differ (Orlich et al., 2013) [11]. In the study’s 2002 to 2006 survey of 60,903 members, 2.9% of vegans had type 2 diabetes against 7.6% of non-vegetarians, and after allowing for age, BMI, exercise, income and other factors the vegans’ odds of having it were about half (odds ratio 0.51, 0.40 to 0.66) [5]. A snapshot like that can’t show which came first, so the researchers then followed 41,387 members who did not have diabetes. On a questionnaire two years later, 0.54% of the vegans reported having developed it, against 2.12% of the non-vegetarians, and after similar adjustments, BMI included, the vegans’ odds were 62% lower (0.38, 0.24 to 0.62) [6]. Whether a plant-based diet can prevent or reverse type 2 diabetes has an answer of its own.

Diet group	Average BMI	Had type 2 diabetes	New cases over two years
Vegan	23.6	2.9%	0.54%
Lacto-ovo vegetarian	25.7	3.2%	1.08%
Pesco-vegetarian	26.3	4.8%	1.29%
Semi-vegetarian	27.3	6.1%	0.92%
Non-vegetarian	28.8	7.6%	2.12%

The first two columns come from the 2009 survey [5] and the last from the 2013 follow-up [6], and all are raw figures, before any adjustment. Blood pressure was lower too in a snapshot of 500 white members who attended the study’s clinics: vegans’ systolic and diastolic pressures were, after adjustment, 6.8 and 6.9 mmHg lower than those of Adventists who ate meat, and their odds of high blood pressure were 63% lower (odds ratio 0.37, 0.19 to 0.74), a gap only partly explained by their lower body weight (Pettersen et al., 2012) [7]. Randomised trials give a narrower picture. A 2022 meta-analysis of 11 trials with 796 participants who had overweight or type 2 diabetes (Termannsen et al.), each running 12 to 26 weeks against people’s usual diet or another diet, found that vegan diets lowered weight by 4.1 kg (2.4 to 5.9) and HbA1c, a measure of long-term blood sugar, by 0.18 percentage points (0.07 to 0.29), but found no effect on blood pressure [16]. The authors added that differences in the make-up and energy content of the diets may account for some of the effect [16].

For cancer, the newest evidence favours plant-based eating overall but not for every cancer. A 2026 meta-analysis of prospective studies (Aune et al.) found 13% less cancer overall in vegetarians (relative risk 0.87, 0.84 to 0.91) and 23% less in vegans (0.77, 0.70 to 0.85), though the vegan figure comes from only three studies, and differences in BMI explained a moderate part of these links [17]. The largest study of the question to date (Dunneram et al., 2026), pooling 1.8 million people in nine cohorts in the UK, US, Taiwan and India, found vegetarians had lower risks of five cancers, among them breast (hazard ratio 0.91, 0.86 to 0.97) and prostate (0.88, 0.79 to 0.97), but almost twice the risk of squamous cell cancer of the oesophagus (1.93, 1.30 to 2.87), and its 8,849 vegans had a 40% higher risk of colorectal cancer (1.40, 1.12 to 1.75) [18]. Dunneram’s authors urged caution in generalising the results, and Aune’s meta-analysis found 14% less colorectal cancer in vegetarians (0.86, 0.76 to 0.97) and no clear difference for vegans (1.02, 0.71 to 1.48) [17]. Separately, in 2015 the World Health Organization’s cancer agency, IARC, classed processed meat as carcinogenic to humans, on sufficient evidence that it causes colorectal cancer, and estimated that each 50 g portion eaten daily raises the risk by 18%, while stressing that for an individual the risk remains small [8].

Could vegetarians just be healthier people?

Vegetarians do tend to have healthier habits, but in the large studies their lower rates of heart disease and diabetes remained after allowing for the habits that were measured. In EPIC-Oxford the people who ate no meat were less likely to smoke, drank slightly less alcohol and were more physically active, and the 22% lower heart disease rate is the figure after allowing for all three [3]. No adjustment can account for habits nobody measured, which is why studies like these show an association and can’t by themselves prove cause.

Randomised trials fill some of that gap. A 2023 meta-analysis of 30 trials (Koch et al.), in which adults were assigned to a vegetarian or vegan diet or to an omnivorous one, found that the plant-based diets lowered LDL cholesterol by 0.30 mmol/L on average (95% CI 0.19 to 0.40), with similar effects across ages, continents, study lengths and states of health [9]. EPIC-Oxford’s vegetarians had about 0.5 mmol/L less total cholesterol than its meat-eaters, and once self-reported high cholesterol, high blood pressure, diabetes and BMI were all allowed for, their lower heart disease rate narrowed to a borderline result (0.90, 0.81 to 1.00), which suggests that part of the benefit works through those risk factors [3].

Is a vegan diet healthy in the long term?

The long-term evidence on vegetarians is generally reassuring, but much less is known about vegans, and not every result favours either group. A 2016 review of the large Western studies by the Oxford researchers Appleby and Key judged vegetarians’ long-term health generally good, and for some conditions possibly better than that of comparable meat-eaters, and said much more research is needed on vegans in particular [10].

Death rates are where the studies disagree. In the Adventist Health Study-2 (Orlich et al., 2013), which followed 73,308 North American Adventists for almost six years on average, vegetarians as a group had a 12% lower death rate than non-vegetarians (hazard ratio 0.88, 0.80 to 0.97), with larger effects in men than in women [11]. For vegans the figure was 0.85, but its range (0.73 to 1.01) could not rule out no difference [11]. A pooled analysis of two British cohorts including EPIC-Oxford (Appleby et al., 2016), covering 60,310 people, found no difference in death rates between vegetarians and comparable regular meat-eaters (1.02, 0.94 to 1.10) [12]. The authors noted that their volunteers were not representative of the UK population [12].

EPIC-Oxford (Tong et al., 2019) also found that vegetarians had a 20% higher rate of total stroke (hazard ratio 1.20, 1.02 to 1.40), mostly because of more haemorrhagic strokes (1.43, 1.08 to 1.90), which works out at about three extra strokes per 1,000 people over ten years, set against the ten fewer cases of heart disease [3]. For vegans alone the stroke estimate was higher (1.35) but too uncertain to be sure of (0.95 to 1.92) [3]. Pooled studies have not settled it: across 12 cohort studies, vegetarians’ stroke risk showed no clear difference from non-vegetarians’ (0.90, 0.77 to 1.05), and for vegans, across five studies, the estimate (1.17, 0.69 to 1.99) was too uncertain to show a link either way; the reviewers called for more research on stroke (Dybvik et al., 2023) [4]. The reason for EPIC-Oxford’s finding is not known, though its researchers raised vegetarians’ low LDL cholesterol, which statin trials have also linked to haemorrhagic stroke, and lower blood levels of some nutrients, B12 among them, as possible contributors that need more research [3]. None of this is a reason to stop taking a statin, and anyone worried should speak to their GP. In a later analysis of the same cohort, vegans had 2.3 times the meat-eaters’ rate of hip fracture after allowing for body weight and lifestyle (hazard ratio 2.31, 1.66 to 3.22), about 15 more hip fractures per 1,000 people over ten years (Tong et al., 2020) [13].

Nothing in these studies shows whether supplements or careful planning would remove those risks. The BDA’s advice is to plan, as with any diet. It says plant foods can provide all the essential nutrients except vitamin B12, for which a vegan’s only reliable sources are fortified foods and supplements [1]. Needing B12 from fortified foods or a supplement is a matter of planning, and the BDA’s list of nutrients to watch, which includes vitamin D, calcium, iron, zinc and iodine, applies to anyone cutting down on animal foods or cutting them out, vegan or not [1].

If you take a statin, blood pressure tablets or diabetes medicine, speak to your GP before making big changes to how you eat, and don’t change or stop any medicine without their advice. If cutting out foods has become a way of restricting how much you eat, a GP or an eating-disorder charity can help: Beat in the UK (beateatingdisorders.org.uk), Bodywhys in Ireland (bodywhys.ie), ANAD in the US (anad.org), NEDIC in Canada (nedic.ca) and the Butterfly Foundation in Australia (butterfly.org.au), while in New Zealand EDANZ (ed.org.nz) supports families and carers.