This article is for educational purposes only and does not replace the advice of a qualified healthcare professional.
Plant-based eating has grown substantially in the UK over the past decade, and for many people a vegan diet is a deeply considered choice, rooted in ethics, environmental concern, health, or some combination of all three.
A well-planned vegan diet can absolutely support good health across the lifespan, and research consistently shows that plant-rich dietary patterns are associated with reduced risk of type 2 diabetes, cardiovascular disease, certain cancers, and all-cause mortality.
The word "well-planned" matters, though, and this article is about what that actually means in practice. There are several nutrients that require specific and deliberate attention on a vegan diet, not because veganism is inherently deficient, but because the richest or most bioavailable sources of these nutrients happen to be animal products.
Knowing which ones they are, why they matter, and where to find or supplement them is empowering rather than restrictive information. It means you can eat in alignment with your values while genuinely taking care of your health.
Vitamin B12: Non-Negotiable
Vitamin B12 is the most critical nutritional consideration for anyone following a vegan diet, and it is the one area where the evidence is unequivocal: B12 cannot be obtained reliably from plant foods, and supplementation or consistent intake of fortified foods is essential, not optional.
B12 is found almost exclusively in animal products including meat, fish, dairy, and eggs.
Some plant foods including certain seaweeds, fermented foods, and nutritional yeast are sometimes cited as B12 sources, but the B12 analogues found in these foods are not reliably bioavailable and cannot be depended upon to meet requirements.
B12 is essential for the production of red blood cells, the maintenance of the myelin sheath that protects nerve fibres, and DNA synthesis. Deficiency develops slowly because the body can store B12 for several years, which means people transitioning to a vegan diet may not notice symptoms for a long time, by which point deficiency can be significant.
Symptoms of B12 deficiency include profound fatigue, weakness, brain fog, low mood, numbness or tingling in the hands and feet, and in severe or prolonged cases, irreversible neurological damage.
The Vegan Society recommends a daily supplement of at least 10mcg of cyanocobalamin (the most stable and well-researched form) or a weekly supplement of 2,000mcg.
Alternatively, consistent daily intake of multiple B12-fortified foods (fortified plant milks, nutritional yeast, fortified breakfast cereals) can meet requirements, but this requires reliable and regular consumption of adequate amounts across the day. If in any doubt, supplementation is the more dependable route.
Getting B12 levels checked periodically through a GP blood test is sensible, particularly in the early years of transitioning to a vegan diet, and for older adults, whose absorption efficiency declines with age regardless of diet.
Omega-3 Fatty Acids: EPA and DHA
The long-chain omega-3 fatty acids EPA and DHA are found primarily in oily fish and other marine sources. While plant foods including flaxseeds, chia seeds, hemp seeds, and walnuts provide ALA (alpha-linolenic acid), the body's conversion of ALA to EPA and DHA is extremely limited, with research suggesting conversion rates of around 5 to 10% for EPA and less than 1% for DHA.
EPA and DHA are critical for brain structure and function, cardiovascular health, visual development, mental health, and lowering inflammation. They are physiologically essential, and blood levels of DHA in particular are consistently lower in vegans than in omnivores across studies.
The solution for vegans is algae-based EPA and DHA supplements. Algae is the original source of these fatty acids in the marine food chain, and algae-derived supplements provide well-absorbed EPA and DHA that has been shown in research to raise blood levels as effectively as fish oil. A daily supplement providing at least 250 to 500mg of combined EPA and DHA is recommended, with higher amounts potentially beneficial for those with specific health concerns including cardiovascular risk, mental health conditions, or during pregnancy.
Continuing to eat ALA-rich plant foods alongside algae-based supplementation is worthwhile, as ALA still contributes to the omega-3 pool and has independent health benefits.
Iodine: An Underappreciated Gap
Iodine is one of the most commonly overlooked nutritional concerns in vegan diets, and research consistently shows that vegans have lower iodine levels than both omnivores and vegetarians..
Iodine is essential for thyroid hormone production, and the thyroid regulates metabolism, energy, growth, and development throughout the body. In UK diets, the primary sources of iodine are dairy products and white fish. Plant milks, which have largely replaced dairy in vegan diets, are not reliably fortified with iodine in the UK, meaning that vegans removing dairy without a conscious replacement strategy are at significant risk of inadequate intake.
Seaweed is exceptionally rich in iodine, but the concentration varies so dramatically between types and even between batches that it is not a reliable or safe sole source. Some varieties, particularly kelp, contain extremely high amounts that can actually suppress thyroid function with regular consumption.
Another source of iodine is iodized salt but for those who consume neither, the most reliable solution for most vegans is a supplement containing iodine (as potassium iodide), at around 140-150mcg, which is the reference nutrient intake for adults. Many vegan multivitamins include iodine, and this is worth checking on the label. Checking whether your plant milk is fortified with iodine (some brands are beginning to add it) is also worthwhile.
Calcium: More Than Just Dairy
Calcium is important for bone health, muscle function, nerve transmission, and cardiovascular health. The concern with vegan diets is twofold: removing dairy, which is the dominant source of calcium in most UK diets, and the variable bioavailability of calcium from plant sources.
The reference nutrient intake for calcium in adults is 700mg per day, rising to around 1,000mg for adolescents and breastfeeding women. This is achievable on a vegan diet, but requires deliberate inclusion of calcium-rich foods consistently.
The best plant-based calcium sources include:
- calcium-set tofu (made with calcium sulphate rather than nigari, which is magnesium chloride: checking the ingredients label is important here)
- fortified plant milks and yoghurts
- edamame
- tempeh
- white beans
- kale
- pak choi
- spring greens
- broccoli
- almonds
- tahini
- dried figs
- fortified plant-based foods.
Calcium bioavailability from plant foods varies considerably. Kale, pak choi, spring greens, and broccoli have good calcium bioavailability, comparable to dairy. Spinach and beet greens, while high in calcium on paper, have very poor bioavailability due to their high oxalate content, which binds calcium and prevents its absorption.
Fortified plant milks typically have calcium bioavailability comparable to dairy milk when well shaken, as the calcium can settle at the bottom of the carton.
Ensuring consistent daily intake of several calcium-rich plant foods, choosing fortified plant milks and yoghurts, and using calcium-set tofu are the most practical strategies.
It is also worth noting that adequate vitamin D is essential for calcium absorption, making vitamin D status directly relevant to calcium adequacy regardless of dietary intake.
Vitamin D
Vitamin D deficiency is common across the UK population regardless of dietary pattern, but it is worth including in any vegan nutrition discussion because the few dietary sources of vitamin D are predominantly animal-based: oily fish, egg yolks, and fortified dairy products.
Most plant-based foods do not naturally contain vitamin D. Some fortified foods including certain plant milks, cereals, and margarines provide vitamin D, but in most cases not enough to meet requirements without sunlight or supplementation.
There are two forms of supplemental vitamin D: D2 (ergocalciferol), which is always plant-derived, and D3 (cholecalciferol), which is traditionally derived from lanolin in sheep's wool, though vegan D3 from lichen is now widely available and equally effective. Research suggests D3 raises blood levels of vitamin D more effectively than D2, making vegan D3 the preferred supplemental form.
A daily supplement of at least 10mcg (400 IU) is recommended for everyone in the UK during autumn and winter, with year-round supplementation appropriate for those who spend limited time outdoors. For those who are deficient, higher doses under GP guidance may be needed.
Iron
Plant foods provide non-haem iron, which is significantly less bioavailable than the haem iron found in meat and fish. This means that while it is entirely possible to meet iron requirements on a vegan diet, it requires more deliberate food choices and attention to absorption strategies.
The key strategies for vegans include:
- eating a wide variety of iron-rich plant foods daily (lentils, chickpeas, kidney beans, tofu, pumpkin seeds, fortified cereals, dark leafy greens, dried apricots)
- pairing these foods with vitamin C to significantly enhance absorption
- avoiding tea, coffee, and calcium-rich foods at the same meal as iron-rich foods.
The reference nutrient intake for iron is 8.7mg per day for men and postmenopausal women, and 14.8mg per day for premenopausal women. Some researchers suggest that those following entirely plant-based diets may benefit from aiming toward the higher end due to lower bioavailability. Ferritin testing through a GP is the most reliable way to monitor iron status, and premenopausal women in particular are worth monitoring regularly given the combination of monthly losses and lower dietary bioavailability.
Zinc
Zinc follows a similar pattern to iron: plant foods contain zinc, but the phytate content of those same foods significantly reduces its bioavailability compared to animal sources.
Estimated zinc bioavailability from a vegan diet is around 15 to 26%, compared to 33 to 35% from a mixed diet.
Good plant-based zinc sources include:
- pumpkin seeds
- hemp seeds
- sesame seeds and tahini
- lentils
- chickpeas
- cashews
- oats
- quinoa
- tofu.
The preparation strategies that improve iron absorption from plant foods, including soaking, sprouting, and fermenting, also improve zinc bioavailability by reducing phytate content.
The recommended nutrient intake for zinc is 9.5mg per day for men and 7mg per day for women, though some researchers suggest vegans may need to aim higher to account for reduced bioavailability. A supplement of 10 to 15mg per day is worth considering for those who consistently struggle to meet zinc needs through diet alone, with the caveat that long-term supplementation above this range requires attention to copper balance.
Selenium
Selenium is an important mineral for thyroid function, antioxidant defence, and immune health, and is an area of genuine concern for those following vegan diets in the UK. UK soils are relatively low in selenium compared to soils in North America, meaning that plant foods grown in the UK tend to have lower selenium content.
Animal foods, particularly fish, meat, and eggs, are the richest sources of selenium in UK diets, and research has found that vegans tend to have lower selenium status than omnivores.
Brazil nuts are the most concentrated plant source of selenium, but the selenium content varies considerably depending on the soil where they were grown, making them an unreliable sole source. Other plant sources include sunflower seeds, wholegrain bread (particularly if made from imported wheat grown in selenium-richer soils), oats, and lentils.
Including a small number of Brazil nuts several times per week alongside other selenium-containing foods is a practical strategy, and a supplement containing selenium (around 55 to 70mcg per day) may be appropriate for those with limited dietary intake, again noting that selenium toxicity is possible at high doses so staying within recommended amounts is important.
Protein
Protein adequacy on a vegan diet is one of the most frequently raised concerns, and also one of the most frequently overstated ones. The majority of vegans eating a varied diet with adequate calories meet their protein requirements. The more nuanced consideration is amino acid completeness.
Animal proteins are complete, meaning they contain all nine essential amino acids in adequate proportions. Most plant proteins are lower in one or more essential amino acids, though soy, quinoa, buckwheat, hemp seeds, and edamame are notable exceptions as complete plant proteins.
The practical solution is variety: eating a wide range of plant proteins across the day naturally provides complementary amino acid profiles without any need for strategic combining at every meal. Regular inclusion of legumes, whole grains, tofu, tempeh, edamame, nuts, and seeds across the day is sufficient for most healthy adults to meet protein and amino acid needs.
Older adults on vegan diets may benefit from paying closer attention to protein intake, as requirements increase with age and the anabolic efficiency of plant protein is somewhat lower than animal protein, meaning slightly higher intakes may be needed to achieve the same muscle protein synthesis response.
Practical Summary
Rather than approaching vegan nutrition with anxiety, it helps to think in terms of a short, manageable list of things to prioritise.
- Supplement B12 daily without exception
- Take an algae-based EPA and DHA supplement daily
- Ensure iodine intake through a supplement or fortified foods
- Choose fortified plant milks consistently and shake them well
- Eat calcium-rich plant foods every day
- Test vitamin D levels and supplement appropriately
- Pay attention to iron and zinc by eating a varied diet and using preparation methods that improve bioavailability
- Get blood levels checked periodically, particularly for B12, vitamin D, iron, and ferritin.
Beyond this list, a varied, colourful, fibre-rich plant-based diet built around whole foods provides an exceptional nutritional foundation. The concerns above are real, but they are manageable. A well-supplemented vegan diet is a well-nourished one.
Conclusion
Vegan diets can absolutely support excellent long-term health, and the evidence for the benefits of plant-rich eating is compelling. Being vegan does not automatically mean being nutritionally deficient: it means being intentional about a handful of specific nutrients that require more attention in the absence of animal products.
References:
https://pmc.ncbi.nlm.nih.gov/articles/PMC10030528/
https://pmc.ncbi.nlm.nih.gov/articles/PMC6835948/
https://pmc.ncbi.nlm.nih.gov/articles/PMC10751939/
https://www.tandfonline.com/doi/full/10.1080/10408398.2022.2084027
https://pmc.ncbi.nlm.nih.gov/articles/PMC10027313/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12174276/
