Vegan vitamins and supplements – B12, vitamin D, iodine, iron, and omega-3
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A well-planned vegan diet can meet most of your nutrient needs, but there are a few nutrients that require special attention. In Finland, the Finnish Food Authority highlights vitamin B12, iodine, and vitamin D as the nutrients most commonly requiring supplementation in a vegan diet. Calcium and iron are supplemented as needed, depending on the diet and individual requirements.
In this guide, we will go through what a vegan should practically check in their own diet and how dietary supplements differ from one another. It is not worth using products just because they are available: it is essential to know which nutrients you need and how much you are already getting from your food.
Also check out FuturePeaks' vegan vitamins and minerals.
Which nutrients are most important for a vegan?
| Nutrient | Why should you pay attention to it? | In practice |
|---|---|---|
| Vitamin B12 | There are very few reliable natural sources in a vegan diet. | Intake must be ensured through fortified products and/or a supplement. |
| Vitamin D | Intake depends on the season, sun exposure, and the use of vitamin D-fortified products. | In Finland, the need for a supplement is emphasized, especially if vitamin D-fortified products are not used regularly. |
| Iodine | Dairy products are a significant source of iodine in the Finnish diet. | Vegans should check their use of iodized salt, fortified plant-based drinks, and any potential supplement. |
| Iron | Plant-based iron is non-heme iron, and its absorption varies depending on the composition of the meal. | Iron supplements do not need to be used automatically. Suspected deficiencies should be assessed through lab tests and healthcare services if necessary. |
| Calcium | As dairy products are excluded, the sources of calcium change. | Calcium-fortified plant-based drinks and other calcium-containing foods are essential. |
| Omega-3 | A plant-based diet typically provides ALA fatty acid, whereas there are fewer direct sources of EPA and DHA. | ALA intake is ensured through, for example, rapeseed oil, nuts, and seeds. Algal oil is a vegan direct source of EPA and/or DHA. |
Vitamin B12 – a nutrient that must be ensured
Vitamin B12 plays a role in, among other things, the formation of red blood cells and the normal functioning of the nervous system. According to the Finnish Food Authority, the recommended daily intake for an adult is about 4 micrograms. Common sources of B12 are animal-based, which is why intake in a vegan diet must be ensured through fortified foods and/or a supplement.
The dose in a supplement is not the same as the daily intake recommendation: the absorption of B12 depends on the dose and frequency of use, so products may contain doses significantly higher than 4 micrograms. Follow the product’s dosage instructions.
Vitamin D in Finland
Vitamin D intake is influenced by diet, the use of vitamin D-fortified products, and vitamin D formed through the skin. According to the Finnish Food Authority, the recommended daily intake for adults is 10 micrograms. A vitamin D supplement is recommended, for example, when vitamin D-fortified products and/or fish are not consumed regularly. For vegans, this makes vitamin D-fortified plant drinks, spreads, and, if necessary, a vegan vitamin D supplement practical options.
A larger dose is not automatically better. It is advisable to avoid unnecessarily high intake of vitamin D and to consider the total amount from both food and supplements.
Iodine – an easily forgotten part of a vegan diet
Iodine is needed for the production of thyroid hormones. According to the Finnish Food Authority, the recommended daily intake for an adult is about 150 micrograms. In Finland, dairy products are traditionally a significant source of iodine, so their exclusion can reduce intake.
Vegans should check whether they are using an iodine-fortified plant drink, iodized table salt, or an iodine-containing supplement. Seaweed is not automatically a good solution, as the iodine levels in different seaweeds can vary significantly.
Does a vegan need an iron supplement?
Not automatically. Legumes, whole grains, seeds, and many other plant-based foods contain iron. However, the absorption of non-heme iron from plants is influenced by the composition of the meal. Food containing vitamin C can improve iron absorption.
It is not advisable to use an iron supplement "just in case" for a long period without a reason. If you suspect an iron deficiency or have symptoms consistent with it, the matter should be investigated through healthcare services and lab tests if necessary.
Calcium – check your plant-based drinks
Calcium can also be obtained from a plant-based diet, but in practice, fortified plant-based drinks are an easy way for many vegans to ensure regular intake. In addition to calcium, it is worth checking the packaging for vitamin D, vitamin B12, riboflavin, and iodine.
Omega-3: ALA is not the same thing as EPA and DHA
Alpha-linolenic acid, or ALA, is an essential omega-3 fatty acid obtained from sources like rapeseed/canola oil, flaxseeds, chia seeds, and walnuts. The Finnish Food Authority recommends the daily use of rapeseed/canola oil or a similar fat source in a vegan diet to support an adequate intake of essential fatty acids.
The body can convert ALA into EPA and DHA, but this conversion is limited. Algal oil provides EPA and/or DHA directly without the need for fish. This does not mean that every vegan automatically needs an algal oil supplement, but it is a practical option if you want a direct vegan source of EPA/DHA.
Read more in our guide on the differences between ALA, EPA, and DHA and check out our vegan omega-3 products.
Does a vegan need a multivitamin?
A multivitamin can be a practical solution, but it is not automatically the best option for everyone. For example, if B12, vitamin D, and iodine are already well-managed through food and separate supplements, a broad multivitamin may be unnecessary. On the other hand, a suitably formulated vegan multivitamin can simplify daily life.
The most important thing is to look at the nutritional content rather than the product name: which nutrients the product contains, how much is in a daily dose, and whether you are already getting the same nutrients from other supplements.
What about zinc, selenium, and other minerals?
These are needed for normal metabolism, but you do not need a separate jar for every single nutrient. A varied vegan diet includes, for example, whole grains, legumes, nuts, and seeds, which provide several minerals. The need for a separate supplement depends on your diet and individual situation.
Frequently asked questions about vegan vitamins
Which vitamin is most important for a vegan?
Vitamin B12 is the nutrient that must be ensured especially carefully in a vegan diet. It is also worth paying special attention to vitamin D and iodine in Finland.
Can vitamin B12 be obtained entirely from plant-based food?
You should not rely on ordinary, unprocessed plant-based products as a source of B12. Use reliably B12-fortified products and/or a supplement.
Does a vegan always need an iron supplement?
No. An iron supplement is necessary when there is an actual need for one. Suspected deficiencies should be investigated rather than taking high doses of iron "just in case."
Is vegan D3 possible?
Yes. Vitamin D3 can also be produced from vegan sources, such as lichen. Check the product packaging or manufacturer information to confirm it is vegan.
Is algal oil the same thing as plant-based ALA?
No. ALA is a short-chain essential omega-3 fatty acid. Algal oil can contain long-chain EPA and DHA fatty acids directly.
Sources
- Finnish Food Authority: Vegan diet
- Finnish Food Authority: Vitamin B12
- Finnish Food Authority: Vitamin D
- Finnish Food Authority: Iodine
- Nordic Nutrition Recommendations 2023
Updated 15.10.2026. This guide provides general nutritional information and does not replace an individual assessment by a healthcare professional.
