Vegan diet and health

Quick answer: Well-planned vegan diets are considered healthy and nutritionally adequate by major dietetic bodies, and vegans tend to have lower cholesterol, blood pressure and rates of type 2 diabetes and heart disease. Large studies have also found a higher risk of fractures and haemorrhagic stroke in some vegan or vegetarian groups, so planning for vitamin B12, calcium, vitamin D, iodine and omega-3 matters. Diet quality counts: a vegan diet based on whole plant foods differs from one based on refined, sugary foods.

Key facts

• The Academy of Nutrition and Dietetics states that appropriately planned vegetarian, including vegan, diets are “healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases”, for all life stages and athletes (Melina et al., 2016).
• In the UK EPIC-Oxford cohort, vegetarians (including vegans) had a 22% lower rate of ischaemic heart disease but a 20% higher rate of total stroke than meat eaters over 18 years (Tong et al., BMJ 2019).
• In the same cohort, vegans had a higher risk of total fractures (hazard ratio 1.43) and hip fractures (2.31) than meat eaters (Tong et al., BMC Medicine 2020).
• “Healthful” plant-based diets (whole grains, fruit, vegetables, nuts, legumes) were linked to lower type 2 diabetes risk in US cohorts; “unhealthful” ones (refined grains, sugary drinks, sweets) were not (Satija et al., 2016).
• Vitamin B12 must come from fortified foods or supplements (Vegan Society).
• Observational studies cannot prove cause and effect: vegans often differ from others in smoking, alcohol, exercise and body weight.

Professional positions

In 2016 the Academy of Nutrition and Dietetics stated that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. The paper reported that these diets are associated with a lower risk of ischaemic heart disease, type 2 diabetes, hypertension, certain types of cancer and obesity, and stated that vegans need reliable sources of vitamin B12, such as fortified foods or supplements (Melina et al., 2016). The NHS likewise says that a healthy vegan diet can provide most nutrients with good planning, highlighting calcium, vitamin D, iron, B12, omega-3, iodine and selenium (NHS).

Major studies

• EPIC-Oxford is a UK cohort, part of the European Prospective Investigation into Cancer and Nutrition, that recruited participants between 1993 and 2001, including a large proportion of vegetarians and vegans.
• Adventist Health Study-2 is a North American cohort of Seventh-day Adventists, a population with a wide range of dietary patterns, including many vegetarians and vegans.

Heart disease and stroke

Vegan diets typically contain little saturated fat and no dietary cholesterol, and are high in fibre. Studies consistently find that vegans have lower average LDL cholesterol levels and lower blood pressure than meat eaters.

A 2019 analysis of 48,188 EPIC-Oxford participants found that vegetarians, including vegans, had a 22% lower rate of ischaemic heart disease than meat eaters (equivalent to 10 fewer cases per 1,000 people over 10 years), partly explained by lower cholesterol, blood pressure, diabetes and body mass index. The same analysis found a 20% higher rate of total stroke (about three more cases per 1,000 people over 10 years), mostly haemorrhagic stroke (Tong et al., 2019). The authors noted that the stroke finding needed further research.

Type 2 diabetes

Data from the Adventist Health Study-2 showed a lower prevalence of type 2 diabetes among vegans than among non-vegetarians, even after accounting for body mass index. Clinical trials have also tested low-fat vegan diets in people with type 2 diabetes and reported improvements in blood glucose control and body weight. Lower body weight among vegans appears to explain part, but possibly not all, of the association.

Cancer

Evidence on cancer is more limited and less consistent. Some analyses from the Adventist Health Study-2 and EPIC-Oxford have reported modestly lower overall cancer incidence among vegetarians or vegans, but findings for individual cancers are often uncertain because of small numbers of cases.

Relevant context includes the 2015 evaluation by the International Agency for Research on Cancer (IARC), which classified processed meat as carcinogenic to humans (Group 1) and red meat as probably carcinogenic to humans (Group 2A), mainly on the basis of colorectal cancer evidence. Diets high in fibre, whole grains, fruit and vegetables are also associated with lower risk of some cancers. However, it is not established that a vegan diet as such prevents cancer.

Bone health

Bone health is an area of concern. In EPIC-Oxford, with an average of 17.6 years’ follow-up, vegans had higher risks of total, hip, leg and other main-site fractures than meat eaters, equivalent to about 15 more hip fractures per 1,000 people over 10 years (Tong et al., 2020). Researchers suggested that lower calcium and protein intakes and lower body mass index may contribute. Adequate calcium, vitamin D and protein, and regular weight-bearing exercise, are therefore emphasised.

Diet quality matters

Not all vegan diets are equal. Harvard researchers using “plant-based diet indices” distinguished between healthful plant-based diets, rich in whole grains, fruit, vegetables, nuts and legumes, and unhealthful ones high in refined grains, sugary drinks and sweets. In three large US cohorts, healthful patterns were associated with lower risk of type 2 diabetes; unhealthful ones were not (Satija et al., 2016). See plant-based vs vegan.

Ornish diet vs vegan diet

The Ornish diet is the eating pattern of a lifestyle programme developed by the American physician Dean Ornish. In his Lifestyle Heart Trial, people with moderate to severe coronary heart disease followed a “10% fat whole foods vegetarian diet” together with aerobic exercise, stress-management training, smoking cessation and group support; after five years, the average narrowing of their coronary arteries had slightly regressed, while it worsened in the usual-care group, and they had fewer cardiac events (Ornish et al., JAMA 1998). That trial was small (48 patients randomised, 35 completing the five-year angiography), so its results are encouraging rather than conclusive.

The Ornish programme describes its diet as low-fat and free of animal protein, “with exception of limited and optional egg whites and nonfat dairy”, and considers 10% or fewer of calories from fat ideal (Ornish Lifestyle Medicine). A vegan diet, by contrast, is defined by what it excludes for ethical reasons (all animal products) and sets no fat target.

In practice, a person can follow both: a whole-food, low-fat vegan diet that leaves out the optional egg whites and dairy meets the Ornish fat guidance while remaining fully vegan. Anyone using either diet to manage heart disease should do so with their doctor, as medication and monitoring may need adjusting.

Nutrients requiring attention

Health organisations commonly highlight the following nutrients for vegans:

1. vitamin B12 – supplementation or fortified foods are essential.
2. vitamin D – especially in winter at higher latitudes.
3. iodine – often low without iodised salt or fortified foods.
4. calcium – important for bone health.
5. Omega-3 fatty acids – long-chain EPA and DHA.
6. iron and zinc – absorption is lower from plant foods.

Sample vegan meal plan and daily schedule

The example below shows how one day of vegan eating can cover the main food groups recommended by the NHS: starchy wholegrains, at least five portions of fruit and vegetables, beans and other proteins, fortified dairy alternatives and omega-3-rich nuts and seeds. It is an illustration only: portion sizes and timings depend on age, activity and appetite, and people with medical conditions should get individual advice.

More plans, shopping lists and batch-cooking tips are in meal planning, and you can browse vegan recipes by course.

Frequently asked questions

Is a vegan diet healthy?

A well-planned vegan diet is considered healthy and nutritionally adequate by the Academy of Nutrition and Dietetics and the NHS. It is associated with lower cholesterol, blood pressure, body weight and type 2 diabetes risk, but it needs reliable sources of B12 and attention to calcium, vitamin D, iodine and omega-3 fats.

What is the difference between the Ornish diet and a vegan diet?

The Ornish diet is a very low-fat, mostly plant-based medical programme that allows limited egg whites and nonfat dairy and includes exercise and stress management. A vegan diet excludes all animal products for ethical reasons and has no fat limit. A low-fat, whole-food vegan diet can satisfy both.

Do vegans have a higher risk of fractures or stroke?

Some large UK studies found higher fracture risk in vegans and higher haemorrhagic stroke risk in vegetarians and vegans than in meat eaters. The reasons are not settled; researchers point to lower calcium and protein intakes and lower body weight. Meeting calcium, vitamin D and protein needs and staying active are sensible steps.

What does a vegan eat in a day?

A typical day might include porridge with fortified plant milk and fruit, a bean or lentil soup at lunch, a tofu or tempeh stir-fry with vegetables and rice for dinner, and snacks such as fruit, nuts or hummus. See the sample plan above.

Should I see a professional before going vegan?

It is a good idea if you are pregnant or breastfeeding, planning a diet for a child, an athlete with high energy needs, or managing a medical condition or medication. A registered dietitian can check your plan.

Sources

• Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016.
• Tong TYN et al. Risks of ischaemic heart disease and stroke in meat eaters, fish eaters, and vegetarians over 18 years of follow-up. BMJ. 2019;366:l4897.
• Tong TYN et al. Vegetarian and vegan diets and risks of total and site-specific fractures. BMC Medicine. 2020;18:353.
• Satija A et al. Plant-based dietary patterns and incidence of type 2 diabetes in US men and women. PLoS Medicine. 2016.
• Ornish D et al. Intensive lifestyle changes for reversal of coronary heart disease. JAMA. 1998;280(23):2001–2007.
• Ornish Lifestyle Medicine – Animal protein, avocados and coconut oil
• NHS – The vegan diet
• The Vegan Society – What every vegan should know about vitamin B12

This article summarises research for general information and is not medical advice. Individuals should consult a doctor or registered dietitian for personal advice.

Last reviewed: 31 October 2026.

See also

• Meal planning
• Vegan pregnancy and children
• Vegan athletes
• How to Go Vegan