Supplements in Vegetarian and Vegan Diets
Which nutrients vegetarians and vegans are most often advised to plan for (B12, vitamin D, iodine, iron, calcium, selenium, omega-3), what the NHS says, and how to check vegan labels.
Content last updated . This page has not been medically reviewed.
Overview
The NHS (UK) says you can get the nutrients you need from a varied, balanced vegan diet that includes fortified foods and supplements, but without planning you could miss out on calcium, iron, vitamin B12, iodine and selenium. [1] It lists vitamin D, B12, iodine, selenium and calcium as nutrients that are more difficult to get on a vegan diet. [1] Vegetarians who regularly eat dairy and eggs are in a different position from vegans, especially for B12. [2] This page lists the nutrients worth a plan; it is not a schedule for every vegetarian or vegan, and a clinician or dietitian can look at your own diet.The nutrients to plan for
| Nutrient | What the NHS says | Official amounts and links |
|---|---|---|
| Vitamin B12 | It is not found naturally in fruit, vegetables and grains, so vegans may not get enough. [3] Sources for vegans are limited and a supplement may be needed. [1] For vegetarians who regularly eat eggs and dairy, intake should be enough. [2] | UK adults 19 to 64: about 1.5 mcg a day; 2 mg or less a day of supplements is unlikely to cause harm (NHS, undated page read 2026). [3] See vitamin B12 and B12 forms compared. |
| Vitamin D | Everyone should consider a supplement in autumn and winter; read the label to check the vitamin D is not of animal origin. [1] | 10 mcg a day; do not take more than 100 mcg (4,000 IU) a day (NHS, 2020). [4] See vitamin D. |
| Iodine | Adults need 140 mcg a day. On a strict vegan diet with no fish, eggs or dairy, consider fortified foods or a supplement, and seek advice from a healthcare professional before using one. [5] | 0.5 mg or less a day of supplements is unlikely to cause harm (NHS, 2020). [5] Seaweed can supply excessive amounts, especially brown seaweed such as kelp. [2] See iodine. |
| Iron | A vegan diet can be high in iron, but plant iron is absorbed less well than iron from meat. Eating vitamin C foods at the same time helps, and tea or coffee during or after main meals does the opposite. [1] | UK: 14.8 mg a day for women 19 to 49, 8.7 mg for women 50 and over and for men 19 and over (NHS, 2020). 17 mg or less a day of supplements is unlikely to cause harm. [6] See iron. |
| Calcium | Vegan sources include fortified unsweetened soya, pea and oat drinks, calcium-set tofu and some greens. [1] | Adults need 700 mg a day (NHS, 2020). [7] See calcium. |
| Selenium | Named by the NHS as a nutrient that needs planning on a vegan diet. [1] | No amount in the pages we read. See selenium. |
| Omega-3 | Vegan sources of the short-chain form (ALA) include ground linseed, chia seeds and walnuts. [1] Algae-based supplements are a vegan source of long-chain omega-3. [2] | See algal oil and fish oil vs algal oil. |
| Zinc | Not highlighted on the NHS vegan page. | Proper evidence not found. We searched the NHS vegan diet and vegan pregnancy pages for zinc and found none; see zinc. |
US intake figures (RDA and upper levels) come from the NIH Office of Dietary Supplements, which we could not read this session, so none are quoted. Product-specific upper limits on labels also differ by country.
Vegan multivitamins
Proper evidence not found on whether vegan multivitamins, as finished products, improve health outcomes; we searched NHS pages and PubMed reviews of multivitamins listed on this page. A "vegan" label tells you only that animal-derived ingredients were left out, not that the amounts suit you. Check B12, iodine, vitamin D and iron on the label against the table, and check the form of each nutrient. A multivitamin does not replace a varied diet; see multivitamins, how to evaluate a supplement formula and quality testing and certifications.Testing and symptoms
Tiredness, pins and needles or memory changes can have many causes. The NHS says B12 deficiency can often be diagnosed from symptoms and a blood test, that most cases are treated with injections or tablets, and that some nervous system problems can be permanent if treatment is late. [8] Anyone who suspects a deficiency should see a clinician, not self-treat. See vitamin B12 deficiency.Frequently asked questions
Do vegans need a B12 supplement?
The NHS says vegans may not get enough B12 and that a supplement may be needed, or fortified foods can be used. [3][1]
Is a vegan diet low in iron?
Not necessarily: the NHS says it can be high in iron, though plant iron is absorbed less well. [1]
Do vegetarians need B12?
Vegetarians who regularly eat eggs and dairy foods should be getting enough, according to the NHS. [2]
Is seaweed a good iodine source?
It is concentrated but can supply too much, especially brown seaweed such as kelp; the NHS does not recommend eating it more than once a week, especially in pregnancy or breastfeeding. [2]
Can I get omega-3 without fish?
You can get the short-chain form (ALA) from seeds and walnuts. [1] The NHS says algae-based supplements are a vegan source of long-chain omega-3 and that conversion from ALA is not thought to be very efficient. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: established nutritional role / deficiency treatment, evidence in adequately nourished people, insufficient evidence, marketing claim.
Pregnancy, children, older adults and medicines
- Pregnancy and breastfeeding: the NHS says vegans need to make sure they get enough vitamins and minerals for their child to develop healthily, and that a vegan pregnancy multivitamin should be one made for pregnancy or without vitamin A. [1][2] See prenatal and postnatal vitamins.
- Children: the NHS says to make sure a child on a vegan diet gets a wide variety of foods to provide energy and vitamins for growth. [1] See vitamins for children and teens.
- Older adults and medicines: proton pump inhibitors and anticonvulsants can affect how much B12 and folate the body absorbs. [8] See medication interactions.
- Kidney and liver conditions: not covered by the sources we read; ask a clinician before adding supplements.
References
- NHS: The vegan diet. Read 2026-10-22.
- NHS: Vegetarian and vegan diets during pregnancy. Read 2026-10-22.
- NHS: B vitamins and folic acid. Read 2026-10-22.
- NHS: Vitamin D. Read 2026-10-22.
- NHS: Iodine. Read 2026-10-22.
- NHS: Iron. Read 2026-10-22.
- NHS: Calcium. Read 2026-10-22.
- NHS: Vitamin B12 or folate deficiency anaemia. Read 2026-10-22.