Plant-based diet: nutrients to watch and how to get them

In short

• People on vegetarian diets can get the nutrients they need when they eat a wide variety of foods.
• Vitamin B12 is not present in plant foods unless they are fortified, so vegans usually need fortified foods or a supplement.
• Plant iron is absorbed less well than iron from meat, so pair it with vitamin C and keep tea or coffee away from meals.
• Calcium, vitamin D, iodine, selenium and omega-3 also need a plan.
• Plant-based does not automatically mean healthy, so build the diet on whole foods.

What counts as a plant-based diet

MedlinePlus describes a vegan diet as excluding all meat and animal products, a lacto vegetarian diet as adding dairy, and a lacto-ovo vegetarian diet as including dairy and eggs. People on these diets can get all the nutrients they need, but the NHS warns that without careful planning you could miss out on calcium, iron, vitamin B12, iodine or selenium. MedlinePlus lists protein, iron, calcium, zinc and vitamin B12 as the nutrients to watch.

Vitamin B12: the one to plan first

Vitamin B12 occurs naturally in animal foods and is not present in plant foods unless they are fortified. The NHS says sources for vegans are limited and that a vitamin B12 supplement may be needed. Fortified breakfast cereals, fortified soya drinks and yeast extract or nutritional yeast flakes can help.

Low B12 can affect the nervous system. MedlinePlus lists loss of balance, numbness or tingling in the arms and legs, and weakness. Other risk factors are age over 50, stomach or intestinal surgery, celiac disease, Crohn disease and pernicious anemia. Ask your clinician about a supplement and whether to check your levels. Do not guess at the form or amount.

Iron and absorbing it

The NHS notes that iron from plants is absorbed less well than iron from meat. It is no reason to avoid plant foods, but a few habits help:

• eat foods rich in vitamin C, such as peppers, citrus fruit or berries, at the same meal as iron-rich foods;
• avoid tea or coffee during or right after meals;
• choose iron sources such as pulses, wholemeal bread and flour, fortified cereals, dark leafy greens, nuts, and dried apricots, prunes and figs.

Low iron can show up as tiredness, weakness, dizziness, shortness of breath and pale skin. MedlinePlus explains that a ferritin blood test shows how much iron your body has stored, which is why it is a common check for people at higher risk of low iron.

Calcium, vitamin D, iodine, selenium and omega-3

1. Calcium.The NHS lists leafy greens such as kale and broccoli, though not spinach, because the body cannot absorb all of its calcium. Other choices are fortified unsweetened soya, pea and oat drinks, calcium-set tofu, sesame seeds and tahini, pulses, calcium-fortified bread and dried fruit.
2. Vitamin D.The NHS suggests everyone consider a daily supplement in autumn and winter. Fortified spreads, cereals and soya drinks help, and the label should say the vitamin D is not of animal origin.
3. Iodine and selenium.The NHS says these are hard to get on a vegan diet and recommends fortified foods or supplements. Talk to your clinician about what suits you.
4. Omega-3.Ground linseed (flaxseed), rapeseed oil, chia seeds, shelled hemp seeds and walnuts are plant sources. The NHS advises eating nuts and seeds rich in omega-3 every day.

Protein and variety

Beans, pulses and other plant proteins can cover your protein needs. Eating a wide variety of foods across the day is the main strategy. The NHS also advises limiting foods high in fat, salt or sugar, since many processed vegan foods are heavy on all three, and eating dried fruit at mealtimes rather than as a snack to reduce harm to teeth.

Remember that vegan does not automatically mean healthy. Chips, soda and white bread are vegan too. A diet built on whole foods such as vegetables, fruit, pulses, nuts and whole grains gives you more nutrients than one built on processed substitutes.

Children, pregnancy and breastfeeding

The NHS notes that you need enough vitamins and minerals in pregnancy and breastfeeding for your baby's healthy development, and that children need a wide variety of foods for energy and growth. MedlinePlus advises contacting a health care provider for personal decisions about diet, especially in pregnancy or childhood. A plant-based plan for a child or a pregnant person should be reviewed by a clinician or dietitian, who can recommend supplements.

Checking in with a clinician

Ask your primary care provider whether blood tests make sense for you, for example vitamin B12 and ferritin, and how often to repeat them. Mention any supplements you take, because they can affect results. Bring a short list of what you eat in a typical week so your clinician or dietitian can spot gaps.

Red flags and when to see a doctor

See a clinician promptly for numbness or tingling in the hands or feet, trouble with balance, weakness, memory problems or confusion, which can signal low B12. Also seek advice for persistent tiredness, dizziness, pale skin or shortness of breath, which can signal low iron, and for a child who is not gaining weight or growing well.

Call 911 for chest pain, severe trouble breathing, or sudden weakness or numbness on one side of the body.

Questions to ask your clinician or dietitian

• Which B12 option and how often is right for me?
• Which blood tests should I have, and how often?
• Am I getting enough calcium, iodine and selenium from what I eat?
• Do I need a vitamin D or omega-3 supplement?
• How should I plan meals for a child or during pregnancy?

Questions and answers

Sources

1. NHS — The vegan diet
2. MedlinePlus — Vegetarian Diet
3. MedlinePlus — Vitamin B12 deficiency
4. MedlinePlus — Ferritin Blood Test

Sources checked on 29 October 2026.