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The Balance of Health
HealthModerate evidence

Is a vegan diet healthy?

The short answer

It can be. Well-planned vegan diets are linked to lower rates of heart disease and type 2 diabetes. But 'vegan' is not the same as 'healthy', and a few nutrients, especially B12, need attention.

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Sample data. The figures and sources on this page are demonstration records showing how evidence will be presented. They are approximate and have not yet been through our review process. Read about how we will verify evidence.

25% lower relative risk
Lower risk of ischaemic heart disease in vegetarians (relative)Multiple countries, 2017. Source: Dinu et al. (2017). SampleRelative risk from observational cohorts. Absolute differences are smaller and depend on baseline risk.

What does the evidence show?

A 2017 meta-analysis of 96 studies found that vegetarian and vegan diets were associated with lower body weight, lower cholesterol, and a roughly 25% lower relative risk of ischaemic heart disease.

The same analysis found no significant difference in overall mortality. Benefits for specific diseases do not always add up to a longer life in the data we have.

Randomised trials confirm that plant-based diets lower LDL cholesterol, which supports the idea that part of the observed benefit is causal.

Vegans who do not take B12 supplements or eat fortified foods have high rates of deficiency, and vegan diets can be low in iodine, calcium, omega-3 fats and vitamin D unless planned.Source 1: Vegetarian, vegan diets and multiple health outcomes: a systematic review with meta-analysis of observational studiesSource 2: Effects of vegetarian diets on blood lipids: a systematic review and meta-analysis of randomized controlled trialsSource 3: How prevalent is vitamin B12 deficiency among vegetarians?

Why does this happen?

Plant-based diets are usually higher in fibre and unsaturated fat, and lower in saturated fat, which improves cholesterol and blood pressure.

But a diet can be vegan and still be built on refined carbohydrates, fried food and sugar. The evidence for benefit is mostly from whole-food plant-based patterns.

Vitamin B12 is made by microbes and enters the food chain through animal products, so plant-based eaters need another source.

Bottom line

A vegan diet built on whole foods, with a B12 supplement, is consistent with good health and probably lowers the risk of heart disease. A vegan diet built on processed food, without B12, is not. The word 'vegan' tells you what someone does not eat, not whether their diet is healthy.

The strongest counterargument

“Vegans are just healthier people, so the diet gets credit it does not deserve”

People who choose vegan diets also tend to exercise more, smoke less and earn more. Comparing them with the average person tells you about lifestyle, not diet.

What's true about it

  • This is a real and serious limitation. Observational studies try to adjust for these differences but cannot remove them entirely.
  • Studies comparing vegetarians with health-conscious meat eaters find smaller differences than those comparing them with the general population.

What may be misleading

  • Randomised trials, which do not suffer from this problem, still find that plant-based diets lower cholesterol and improve blood sugar control.
  • The biological mechanisms (fibre, saturated fat, body weight) are well established independently.

What remains uncertain

  • The size of the benefit attributable to diet alone, and whether it applies equally to a poorly planned vegan diet.

Evidence strength

Moderate evidenceHow ratings work

Why this rating: Consistent observational evidence supported by trials on intermediate markers, but few studies isolate vegan diets, mortality findings are mixed, and confounding by lifestyle is real.

Supported by good-quality studies that point the same way, but with gaps: fewer studies, mostly observational data, or some inconsistency.

What remains uncertain?Open questions the evidence does not yet settle.
  • Long-term outcomes for people who have been vegan since childhood.
  • Whether the modest differences in bone fracture rates seen in some vegan cohorts are due to calcium, body weight or something else.
Methodology: how we know thisHow the numbers were produced and what they leave out.
  • We prioritise systematic reviews and meta-analyses over single studies.
  • We distinguish relative risk (25% lower) from absolute risk, which depends on a person's starting point.
  • We treat association as evidence for, but not proof of, causation unless trial evidence exists.

Read our full evidence methodology.

Claims used on this page3 claims, each with its own record, rating and sources.

Sources

Each source links to our record of what it found, its limitations and what we used it for, with a link to the original.

  1. 1
    Vegetarian, vegan diets and multiple health outcomes: a systematic review with meta-analysis of observational studies

    Monica Dinu, Rosanna Abbate, Gian Franco Gensini et al. (2017). Critical Reviews in Food Science and Nutrition.

    Meta AnalysisMeta AnalysisModerate evidenceSampleView original ↗
  2. 2
    Effects of vegetarian diets on blood lipids: a systematic review and meta-analysis of randomized controlled trials

    Fenglei Wang, Jusheng Zheng, Bo Yang et al. (2015). Journal of the American Heart Association.

    Meta AnalysisRandomised Controlled TrialModerate evidenceSampleView original ↗
  3. 3
    How prevalent is vitamin B12 deficiency among vegetarians?

    Roman Pawlak, Scott Parrott, Sudha Raj et al. (2013). Nutrition Reviews.

    Systematic ReviewSystematic ReviewStrong evidenceSampleView original ↗

A note on health information. This page summarises published evidence for a general audience. It is not medical advice and cannot account for your circumstances. If you are changing your diet with a health condition, during pregnancy, or for a child, talk to a doctor or registered dietitian.