Research-backed comparison
Vegan vs Vegetarian Health Benefits: What the Research Actually Shows (2026)
Both diets are significantly healthier than a standard Western diet. The difference between vegan and vegetarian is smaller than most people think -- but the data does show a measurable vegan advantage for specific conditions.
62%
Lower type 2 diabetes risk for vegans vs omnivores (Adventist Health Study-2)
24.1
Average BMI for vegans vs 28.8 for omnivores in the same study
10-12%
Lower overall cancer risk for vegetarians and vegans vs meat-eaters (EPIC-Oxford)
32%
Lower ischaemic heart disease risk for vegetarians vs meat-eaters (EPIC-Oxford)
Comprehensive Health Marker Comparison
The most comprehensive data on plant-based diet health outcomes comes from the Adventist Health Study-2 (AHS-2), which followed over 96,000 participants across different diet groups for multiple years. Here is what the data shows for key health markers:
| Health Marker | Vegan Impact | Vegetarian Impact | Source |
|---|---|---|---|
| Type 2 diabetes risk | 62% lower vs omnivore | 38% lower vs omnivore | AHS-2, 2013 |
| Average BMI | 24.1 (healthy range) | 26.7 (low overweight) | AHS-2 |
| Ischaemic heart disease | ~32% lower (estimated) | 32% lower vs meat-eaters | EPIC-Oxford, 2019 |
| Blood pressure | Lower systolic and diastolic | Lower than omnivore | Multiple meta-analyses |
| Total cholesterol | Significantly lower | Moderately lower | European Heart Journal, 2023 |
| LDL cholesterol | ~30% lower vs omnivore | ~20% lower vs omnivore | Meta-analysis, Dinu 2017 |
| Overall cancer risk | ~14% lower vs omnivore | ~10% lower vs omnivore | EPIC-Oxford |
| Colorectal cancer | 18% lower | 22% lower | AHS-2 cancer study |
| All-cause mortality | ~9% lower vs omnivore | ~8% lower vs omnivore | EPIC-Oxford |
Nutrient Adequacy: What Each Diet Provides
Both diets can be nutritionally complete with planning. The key differences lie in how much planning is required and which nutrients need attention.
| Nutrient | Vegan | Vegetarian (Lacto-Ovo) | Recommendation |
|---|---|---|---|
| Vitamin B12 | DEFICIENT -- must supplement | Adequate from dairy/eggs | Vegans: 250mcg/day cyanocobalamin |
| Vitamin D | Often low (climate-dependent) | Often low (climate-dependent) | Both: 1,000-2,000 IU/day in winter |
| Iron | Lower bioavailability (non-heme) | Better -- eggs contain heme iron | Vegans: eat with vitamin C |
| Calcium | Lower without fortified foods | Adequate from dairy | Vegans: fortified plant milk |
| Omega-3 (DHA/EPA) | Very low -- algae oil needed | Low -- eggs provide some | Both: algae oil supplement |
| Zinc | Lower bioavailability | Better from dairy/eggs | Vegans: soak/sprout legumes |
| Iodine | Very low (no dairy/fish) | Moderate from dairy | Vegans: iodised salt or supplement |
| Protein | Adequate with variety | Easy -- dairy and eggs help | Both: varied diet |
The B12 Deep Dive
Critical for vegans: Vitamin B12 is found only in animal products and fortified foods. B12 deficiency can take 2-5 years to become symptomatic and can cause irreversible neurological damage if untreated.
B12 supplement recommendations for vegans:
- Daily dose: 250mcg cyanocobalamin (the most stable form)
- Weekly dose: 2,500mcg once per week (if you prefer weekly dosing)
- Testing: Blood test every 12-24 months to confirm adequate levels
- Deficiency symptoms: Fatigue, tingling in hands/feet, cognitive changes -- these appear after years of deficiency
- Note: Methylcobalamin is also effective but less studied. Both forms are safe.
Risks and Honest Concerns
Both diets are associated with health benefits, but poorly planned versions carry risks:
- Junk food vegan: Oreos, many crisps, and heavily processed vegan foods are technically vegan but not healthy. A diet of plant-based fast food does not confer the health benefits seen in studies of whole-food plant-based eaters.
- Orthorexia risk: Both diets can become overly restrictive if taken to an extreme. If food anxiety and rule-following are causing stress, speak with a dietitian or mental health professional.
- Calorie restriction: Some new vegans accidentally under-eat because plant foods are less calorie-dense. This is especially a concern for athletes and growing teenagers.
- Eating disorder history: Anyone with a history of disordered eating should consult a professional before adopting a restrictive diet framework.
Who Should Consult a Doctor Before Starting
Consult a registered dietitian or doctor before starting either diet if you are: pregnant or planning pregnancy, breastfeeding, under 18, over 65, have a history of eating disorders, are on blood thinners (vitamin K interactions), or have kidney disease (protein and potassium considerations).
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Protein Sources Guide →Cost Comparison →Getting Started →Kids & Families →Athletes & Performance →Quick Verdict
Both diets significantly reduce risk of heart disease, type 2 diabetes, and cancer vs the standard Western diet. Vegan shows marginally better outcomes in most studies, but requires B12 supplementation. Vegetarian is easier to maintain nutritionally without supplements.
Health Questions Answered
Is vegan healthier than vegetarian?
Vegan diets show marginally better outcomes for heart disease and type 2 diabetes in large cohort studies. The Adventist Health Study-2 found vegans had 62% lower risk of type 2 diabetes and lower average BMI than both vegetarians and omnivores. However, vegans require B12 supplementation and need to monitor iron, zinc, and omega-3 intake more carefully than vegetarians who eat dairy and eggs.
What is the B12 risk for vegans?
B12 deficiency is the main nutritional risk for vegans. Unlike vegetarians who consume dairy and eggs, vegans have no reliable food source of B12 unless they eat fortified foods. B12 deficiency can take years to develop and cause irreversible nerve damage. Every vegan should supplement with at least 250mcg of cyanocobalamin daily or 2,500mcg weekly. Blood tests every 1-2 years are recommended.
Do vegetarian diets reduce cancer risk?
Yes. EPIC-Oxford data shows vegetarians and vegans have approximately 10-12% lower overall cancer risk than meat-eaters. Colorectal cancer risk is significantly lower in both groups. However, the difference between vegan and vegetarian cancer rates is small. The biggest cancer risk reduction comes from eliminating red and processed meat, which vegetarians have already done.
What nutrients do vegans need to supplement?
Vegans should reliably supplement: vitamin B12 (critical, no plant sources), vitamin D3 (especially in northern climates), and algae-based omega-3 DHA/EPA. Additionally, vegans should be aware of iron (eat vitamin C with iron-rich foods), zinc (soaking and sprouting legumes improves absorption), iodine (seaweed or supplements), and calcium (fortified plant milks or calcium-set tofu). Vegetarians who consume dairy and eggs are less likely to need supplementation beyond B12 and vitamin D.