15 min read
What does "plant-based" mean? The spectrum
"Plant-based" is used loosely. The guide covers the full spectrum.
Omnivore
All food groups, including meat, fish, dairy, eggs.
~82% of UK adults.
Flexitarian
Plant-forward, with occasional meat or fish. No strict definition.
~13% of UK adults (YouGov 2024).
Pescatarian
No meat or poultry, but fish and seafood eaten. Often dairy and eggs too.
Lower cancer mortality than meat-eaters in EPIC-Oxford.
Vegetarian
No meat or fish. Lacto-ovo vegetarians eat dairy and eggs.
The most established plant-based pattern.
Vegan
No animal products of any kind. No meat, fish, dairy, eggs, or honey.
Most demanding to plan nutritionally.
A note on terminology: "Plant-based" is increasingly used in food marketing to mean products with some plant-derived ingredients, including highly ultra-processed plant-based meat alternatives. This page focuses on whole food plant-based eating patterns, not branded plant-based products specifically.
The health benefits. What the evidence shows
The largest UK evidence base on plant-based eating comes from EPIC-Oxford. The European Prospective Investigation into Cancer and Nutrition Oxford cohort, established in the 1990s and tracking 65,000 UK adults across different dietary patterns. The findings below draw primarily on EPIC-Oxford, supplemented by other major cohort studies.
Cardiovascular health
Vegetarians and vegans in EPIC-Oxford have consistently lower BMI, lower serum LDL cholesterol (by approximately 0.5 mmol/L on average), and lower blood pressure than comparable meat-eaters. These are all established cardiovascular risk factors.
In terms of disease outcomes: vegetarians (including vegans) had a 22% lower rate of ischaemic heart disease than meat-eaters over 18 years of follow-up. Equivalent to roughly 10 fewer cases per 1,000 people over 10 years. An umbrella review of studies on plant-based diets and cardiovascular health confirmed significantly lower risk of ischaemic heart disease and CVD mortality in vegetarian and vegan diets.
Type 2 diabetes
Both vegetarian and vegan diets are consistently associated with substantially lower rates of type 2 diabetes in large cohort studies. Lower BMI is a major contributing factor, but lower saturated fat intake, higher fibre intake, and better glycaemic profiles of plant-heavy diets also contribute independently.
Cancer
EPIC-Oxford found 18% lower overall cancer incidence in vegans compared to meat-eaters, with lower rates of stomach cancer, haematological cancers, and pancreatic cancer across vegetarian and vegan groups.
Other conditions
EPIC-Oxford has found lower rates of diverticular disease, kidney stones, cataracts, and gallstones in vegetarians and vegans. Lower rates of overweight and obesity are consistently observed.
The quality caveat. Healthy vs unhealthful plant-based diets
Research using the plant-based diet index (PDI) and its derivatives shows that the benefits are driven specifically by healthful plant foods. Vegetables, fruits, whole grains, legumes, nuts, and seeds. Not by all plant foods indiscriminately.
An unhealthful plant-based diet (high in refined grains, potatoes, sugary drinks, and sweets, with minimal animal products) is associated with worse health outcomes than a moderate omnivorous diet. Ultra-processed plant-based foods (crisps, white bread, sugary cereals, processed snacks) do not confer the benefits seen with whole food plant-based patterns. See whole foods and ultra-processed foods.
This means "plant-based" is not sufficient. Quality of the plant foods consumed is what drives the benefit.
The risks. What the evidence also shows
A balanced account of plant-based eating must include the less positive findings from EPIC-Oxford.
Lower risk in vegetarians and vegans
- −22% ischaemic heart disease (EPIC-Oxford, 18-year follow-up)
- −18% overall cancer incidence in vegans
- Substantially lower type 2 diabetes
- Lower rates of diverticular disease, kidney stones, cataracts, gallstones
- Lower BMI, LDL cholesterol, blood pressure
Higher risk in vegetarians and vegans
- +20% total stroke risk (driven by haemorrhagic stroke)
- +9% total fracture risk in vegetarians
- +43% total fracture risk in vegans, including ~2.5× hip fracture risk
- Higher rates of B12 deficiency: 52% of vegans had levels below threshold
Higher stroke risk
EPIC-Oxford found that vegetarians and vegans combined had approximately 20% higher risk of total stroke than meat-eaters, driven primarily by haemorrhagic stroke (bleeding into the brain). Fish-eaters showed no increase in stroke risk. Possible contributing factors include lower intakes of B12 (elevated homocysteine is a stroke risk factor), lower dietary cholesterol (relevant to haemorrhagic stroke specifically), and lower omega-3 status. Whether adequate B12 supplementation, omega-3 from algae, and overall dietary quality can eliminate this risk is not yet established.
Higher bone fracture risk
The EPIC-Oxford fracture study (Tong et al., BMC Medicine, 2020) found vegetarians at 9% higher risk of total fractures vs meat-eaters; vegans at 43% higher risk, including twice the risk of leg fractures and a nearly 2.5-fold higher hip fracture risk. The fracture risk in vegans is likely driven by lower bone mineral density, which in turn reflects lower intakes of calcium, protein, vitamin D, and possibly zinc.
This risk is likely modifiable. The vegans in earlier EPIC-Oxford cohorts had lower calcium intakes than necessary and were not routinely supplementing. Vegans with adequate calcium (from fortified foods, calcium-set tofu, and leafy greens) and vitamin D (from supplementation) should theoretically have better bone health than those who are inadvertently deficient. However, the data on whether well-supplemented vegans maintain comparable bone mineral density to meat-eaters is not yet definitive.
The nutrients that need specific attention
This is the most important section for practical plant-based eating. These are the nutrients that do not appear reliably in plant foods, appear in lower amounts, or appear in less bioavailable forms.
Vitamin B12 Non-negotiable
Vitamin B12 is found almost exclusively in animal products. No plant food contains meaningful, reliable amounts of B12. Seaweed, fermented foods, and nutritional yeast are sometimes cited. None provides a reliable, consistent source at adequate levels. Deficiency causes irreversible neurological damage, megaloblastic anaemia, fatigue, and cognitive decline.
In EPIC-Oxford, 52% of vegans had serum B12 concentrations below deficiency threshold. Compared to 7% of vegetarians and less than 1% of meat-eaters. This is not a minor concern.
Every vegan must take a B12 supplement or consistently eat B12-fortified foods. This is not optional.
Supplement guidance (Gibbs & Cappuccio, Dietetics 2024):
- 50 to 100µg of cyanocobalamin daily (the most studied, stable form)
- Or 2,000µg twice weekly. High passive-diffusion doses are needed because B12 from supplements is absorbed less efficiently than from food
- Fortified foods (plant milks, cereals, nutritional yeast, yeast extract) can also contribute, but require consistent consumption of multiple fortified foods daily to be reliable
Vegetarians who eat eggs and dairy regularly may get sufficient B12 from those sources, but B12 status can decline over time, particularly in older adults. Blood testing every 1 to 2 years is sensible for all vegans.
Iodine Most overlooked
Iodine is essential for thyroid hormone production and is critically important during pregnancy for fetal brain development. In the UK, dairy milk is the primary dietary source of iodine, with fish as the secondary source. Neither is present in vegan diets.
Many plant milks are not iodine-fortified. This varies considerably by brand. Always check the label. Seaweed is extremely variable in iodine content and cannot be relied upon. Some seaweed varieties provide far in excess of the safe upper limit (600µg/day for adults).
- Choose plant milks fortified with iodine (≥22.5µg per 100ml, equivalent to dairy milk)
- Consider an iodine supplement of 150µg/day, particularly during pregnancy and breastfeeding. Avoid kelp supplements (unreliable dosing)
Calcium Bones, blood pressure
Dairy provides approximately 34% of dietary calcium for UK adults. Vegans must replace this deliberately. The EPIC-Oxford bone fracture findings make inadequate calcium the most plausible main driver of higher fracture risk.
| Food | Calcium per typical serving |
|---|---|
| Fortified plant milk (200ml) | ~240mg |
| Calcium-set tofu (100g) | ~200–350mg |
| Kale, cooked (100g) | ~150mg |
| White bread (2 slices, UK fortified) | ~100mg |
| Tahini (1 tbsp, 15g) | ~100mg |
| Almonds (30g) | ~75mg |
| Tinned white haricot beans (100g) | ~65mg |
| Chia seeds (1 tbsp, 10g) | ~55mg |
| Broccoli, cooked (100g) | ~50mg |
Practical guidance: use calcium-fortified plant milk consistently. Eat calcium-set tofu regularly (only calcium-set varieties qualify; check the label). Include leafy greens (kale, pak choi, watercress; spinach is poor due to oxalates). Aim for 700mg/day (UK RNI), 1,000mg+ for post-menopausal women.
Vitamin D UK-wide problem
Vitamin D deficiency is extremely common in the UK for all adults. UK sunlight cannot produce vitamin D between October and March. The NHS recommends 10µg (400 IU) per day supplementation for everyone in autumn and winter. Most standard supplements use D2 (plant-derived); D3 (cholecalciferol) is more effective at raising blood levels and is usually animal-derived (from lanolin). Lichen-derived D3 supplements suitable for vegans are increasingly available.
- 10µg (400 IU) daily October to March (lichen-derived D3 if available)
- Higher doses (25µg / 1,000 IU) may be appropriate if rarely outdoors or have darker skin. Discuss with GP
- Blood testing every 1 to 2 years is sensible
Omega-3 (EPA and DHA) Marine fat gap
Plant ALA (walnuts, flaxseed, chia, hemp, rapeseed oil) converts to EPA at only 5 to 10%, and to DHA at less than 1%. Without oily fish, vegans and vegetarians have significantly lower EPA and DHA. This may contribute to the higher stroke risk seen in EPIC-Oxford.
- Take an algae-derived EPA+DHA supplement, 250 to 500mg combined per day. Algae oil provides identical EPA and DHA to fish oil from the original source
- Eat ALA-rich plant foods daily (ground flaxseed, chia, walnuts, rapeseed oil) alongside supplementing
See omega-3 and omega-6 for the detail.
Iron Absorption matters
Plant foods contain only non-haem iron, which is absorbed less efficiently than haem iron from meat. UK vegans and vegetarians typically eat more iron-rich plant foods, and the body up-regulates absorption when haem iron is absent, partially compensating.
Best plant iron sources: lentils and legumes (lentils, chickpeas, kidney beans, soybeans, tofu); pumpkin, hemp, sesame seeds; dark leafy greens; dried apricots, raisins, figs; fortified cereals; quinoa; wholegrain bread.
Critical practical tip: consuming vitamin C alongside non-haem iron substantially increases absorption (3 to 6 fold). Add a squeeze of lemon to lentils, eat berries alongside iron-rich meals, include red peppers. Avoid tea and coffee with iron-rich meals (leave a 1-hour gap). Women of reproductive age and pregnant women have particularly high iron requirements and should consider blood testing.
Zinc Phytate interference
Zinc is found in plant foods (legumes, whole grains, nuts, seeds) but phytic acid (phytate) binds zinc and reduces absorption. The UK FEED study (2024) found higher proportions of vegans below estimated average requirements for zinc.
Strategies to improve zinc absorption:
- Soak and cook dried legumes (reduces phytate)
- Sprout beans, seeds, grains (germination reduces phytates)
- Use leavened bread (sourdough fermentation reduces phytate); tempeh fermentation increases zinc bioavailability
Best plant zinc sources: pumpkin seeds, hemp seeds, cashews, quinoa, wholegrain bread (leavened), tempeh, tofu, legumes.
Selenium UK-specific
UK soils are selenium-poor, so plant foods grown in the UK are generally lower in selenium than in countries like the US or Brazil. About half of UK women and a quarter of UK men already have low selenium intakes. Vegans avoiding the main animal sources are at heightened risk. Selenium is important for thyroid function, immune function, fertility, and antioxidant defence.
Brazil nuts: 1 to 2 per day provides adequate selenium. The simplest food-based solution. Selenium content varies widely. A modest 55 to 100µg/day supplement is an alternative. Avoid high-dose selenium (narrow safety margin; do not exceed 200µg/day).
Protein on a plant-based diet
This is one of the most commonly asked questions, and one where anxiety often exceeds reality. Most UK vegans and vegetarians get adequate total protein, as confirmed by the FEED study. The UK RNI is 0.75g protein per kg body weight per day. Achievable without animal products.
What requires attention
The main considerations are protein quality and adequacy for higher-need groups. Animal proteins are "complete". Plant proteins are often low in one or more essential amino acids. However, eating a variety of plant proteins across a day provides all essential amino acids without needing to combine specific foods at every meal. The old "complementary protein" idea (rice + beans at every meal) has been superseded.
High-protein plant foods
- Soy products. Edamame, tofu, tempeh, soy milk. Complete proteins; among the best plant sources.
- Seitan (wheat gluten). Very high protein (~25g/100g) but contains few other major nutrients. Not suitable for coeliac disease.
- Legumes. Lentils (~9g/100g cooked), chickpeas (~9g), black beans (~9g), kidney beans (~9g).
- Quinoa. Complete protein (~8g/100g cooked).
- Hemp seeds (~32g/100g) and pumpkin seeds (~30g/100g).
For older adults (65+): the ESPEN recommendation of 1.0 to 1.2g protein per kg body weight to prevent sarcopenia is harder to achieve without meat. Older vegans and vegetarians should actively prioritise protein-rich plant foods at every meal and may benefit from a vegan protein supplement (pea, soy, or hemp protein) if struggling. See the protein guide.
Plant-based food swaps that work, and those that need caution
Not all plant-based alternatives are equal. The site's food scanner is useful here. NOVA processing levels and ingredient lists reveal a great deal.
Swaps that work well
- Oily fish → algae-derived EPA/DHA supplement + walnuts + flaxseed
- Dairy milk → iodine and calcium-fortified plant milk (check the label)
- Meat protein → tofu, tempeh, legumes, edamame, soy products
- Greek yoghurt → soy-based yoghurt with live cultures (for gut health and protein)
- Eggs (protein) → tofu, legumes; for baking, flaxseed or chia "eggs"
Swaps that need caution
- Dairy milk → many oat/almond/rice milks. Check for iodine and calcium fortification; protein is much lower (0.5g vs 3.5g per 100ml)
- Meat → ultra-processed plant-based meat alternatives. Some are NOVA Group 4 with high sodium and additives. Check the label for protein, B12 fortification, sodium, and ingredient list length. See UPF guide.
- Eggs → Quorn. Most Quorn products contain egg white and so are not vegan, though mycoprotein is an excellent protein source for vegetarians
- Cheese → vegan cheese alternatives. Most are very low in protein and not calcium-fortified. Fine for flavour, not a nutritional dairy replacement
Plant-based eating at different life stages
Pregnancy and breastfeeding
A well-planned vegan diet during pregnancy is achievable but requires particularly rigorous planning and supplementation:
- B12. Supplement consistently throughout. Maternal deficiency depletes fetal B12, with potentially irreversible consequences
- Iodine. 150 to 200µg/day unless confirmed adequate from iodine-fortified plant milks
- DHA. Algae-derived, 200 to 300mg/day (EFSA recommendation)
- Calcium. 700mg+/day from fortified milk, calcium-set tofu, kale
- Iron and vitamin D. Standard pregnancy recommendations (10µg vitamin D throughout; iron monitored via blood test)
Pregnant women on a plant-based diet should work with a registered dietitian for personalised guidance.
Infants and young children
Vegan diets in infancy and early childhood require particularly careful planning. Nutrient deficiencies, especially B12, iodine, vitamin D, and calcium, can have serious developmental consequences if not addressed.
This page does not constitute advice for infant feeding. Parents wishing to raise children on a vegan diet should seek advice from a registered dietitian, GP, or health visitor and follow NHS / BDA guidance on vegan infant feeding.
Older adults (65+)
Protein requirements increase with age. B12 absorption from food (both animal and fortified plant foods) declines with age due to reduced stomach acid and intrinsic factor; supplemental B12 becomes increasingly important. Calcium and vitamin D requirements for bone health are also heightened. Regular blood testing (B12, vitamin D, iron, calcium) is sensible for older vegans.
Teenage girls
Higher iron requirements (menstruation) and the need for calcium during bone development (peak bone mass is established by the late teens) make this a nutritionally important group. The FEED study found higher rates of inadequate zinc, iodine, and selenium intakes among younger UK women on plant-based diets.
The supplement summary
| Nutrient | Who needs it | Dose | Notes |
|---|---|---|---|
| Vitamin B12 | All vegans (essential); vegetarians (advisable) | 50–100µg cyanocobalamin daily, or 2,000µg twice weekly | The only genuinely non-negotiable supplement for vegans |
| Vitamin D | All UK adults October–March; year-round if low sun exposure | 10µg (400 IU) minimum; 25µg (1,000 IU) if rarely outdoors | Lichen-derived D3 available for vegans; D2 is an alternative |
| Iodine | Vegans/vegetarians without consistently iodine-fortified plant milk | 150µg/day; 200µg+ in pregnancy | Avoid kelp supplements. Unreliable dosing |
| Algae EPA+DHA | Vegans; vegetarians not eating oily fish | 250–500mg combined per day | Identical to fish oil. Derived from microalgae, the original source |
| Calcium | Vegans with low dairy alternative / fortified food intake | Aim for 700mg/day from food; supplement if unable to meet | Food first. Fortified plant milk, calcium-set tofu, leafy greens |
| Selenium | Vegans and vegetarians in UK (low-selenium soil) | 1–2 Brazil nuts daily, OR 55–100µg supplement | Do not exceed 200µg/day. Narrow safety margin |
| Iron | Women of reproductive age; pregnant women; those with low levels | Test first; supplement if anaemic (not prophylactically for most) | Pair with vitamin C to enhance absorption |
| Zinc | Vegans (phytate-inhibited absorption) | Food strategies first; low-dose supplement if blood test confirms deficiency | Soak legumes; choose leavened bread; eat pumpkin seeds |
Key numbers at a glance
Sources and references
- Key TJ et al. Plant-based diets and long-term health: findings from the EPIC-Oxford study. Proceedings of the Nutrition Society 2022;81:190–198.
- Tong TYN et al. Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study. BMC Medicine 2020;18:353.
- 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.
- Gibbs J, Cappuccio FP. Common nutritional shortcomings in vegetarians and vegans. Dietetics 2024;3:114–128.
- Gardner JK et al. Assessing performance of contemporary plant-based diets against UK dietary guidelines: findings from the FEED study. Nutrients 2024;16:1345.
- British Dietetic Association. Vegetarian, vegan and plant-based diet food fact sheet. bda.uk.com.
- NHS. The vegan diet. nhs.uk.
- Koeder C, Perez-Cueto FJA. Toward supplementation guidelines for vegan complementary feeding. Food Science & Nutrition 2024.
- Cardiovascular health and cancer risk associated with plant-based diets: an umbrella review. Frontiers in Cardiovascular Medicine 2024.
Protein →
How much protein you actually need, the best UK food sources, and the plant vs animal debate.
Omega-3 and Omega-6 →
Why algae oil is the most direct vegan source of EPA and DHA, and how plant ALA fits in.
Whole Foods →
Why every dietary pattern linked to longer life is built around whole foods, and what plant-based eaters should prioritise.