What Supplements Do Vegans and Vegetarians Need? Start With B12

October 20, 2026By VitOptics Staff

Short answer: If you eat vegan, plan for vitamin B12 first. MedlinePlus says B12 is not present in plant foods unless fortified, so on a vegan diet it comes from fortified foods, some nutritional yeast products or a supplement. Iron, zinc, iodine, calcium, vitamin D and omega-3s are worth a closer look too, but whether you need any of them in supplement form depends on what you eat, what you already take and, ideally, your own lab results.

A well-planned vegetarian diet can meet your nutrition needs, according to MedlinePlus, which also notes that the more restrictive a diet is, the harder it can be to get certain nutrients. This guide helps you see where your gaps might be, so you can tell us your diet in the free assessment or bring a clear list of questions to your doctor, dietitian or pharmacist.

Vitamin B12: why plant foods don't supply it

Vitamin B12 "helps in the formation of red blood cells and in the maintenance of the nervous system," in MedlinePlus's words. It is found naturally in fish, meat, poultry, eggs, milk and milk products. For people who eat no animal foods, the practical sources are fortified foods, such as some breakfast cereals and soy products, some nutritional yeast products, and supplements. MedlinePlus notes that the B12 used to fortify foods is very easy to absorb.

MedlinePlus lists following a vegetarian or vegan diet among the situations in which B12 deficiency is most common, alongside being over 50, stomach or intestinal surgery and digestive conditions such as celiac disease. Its advice is to talk to your health care provider about taking vitamin B12 supplements. The adult RDA is 2.4 mcg a day.

B12 also matters if you take certain medicines. If you are vegan and take metformin, read why metformin may lower vitamin B12, and ask your doctor about your B12 status.

Omega-3s: ALA from plants, DHA and EPA from algal oil

There are different kinds of omega-3s. NCCIH explains that ALA is found in plant oils such as flaxseed, soybean and canola oil and in foods such as chia seeds and walnuts, while EPA and DHA are found in seafood and fish oil. Most of the research on omega-3s has focused on EPA and DHA.

If you don't eat fish, NCCIH notes that "algal oils are a vegetarian source of DHA; some also contain EPA." When you compare products, check the Supplement Facts panel for the amounts of EPA and DHA themselves, not only the total omega-3 or total oil. If you take a blood thinner, read about fish oil and other supplements with blood thinners and talk to whoever manages that medicine before adding any omega-3.

Iron: plant iron is harder to absorb, so check before adding a supplement

"You need iron for your red blood cells," MedlinePlus says, and "your body does not absorb the type of iron found from plant foods as well as from the type found in meat and other animal foods." Beans, lentils, leafy greens and fortified cereals all supply iron. Eating foods high in vitamin C at the same meal, such as tomatoes, citrus, bell peppers or strawberries, increases iron absorption.

Iron is a supplement to add with a reason, such as a lab result or your clinician's advice, rather than by default. People with hemochromatosis, a genetic condition that leads to too much iron in the body, are managed with "no iron supplements," according to MedlinePlus's iron page. MedlinePlus also notes that children can sometimes develop iron poisoning by swallowing too many iron supplement pills or liquid, so keep every iron product out of their reach.

Zinc and iodine: two easy-to-miss nutrients

Zinc. "Zinc is important for the immune system and cell growth," and MedlinePlus explains that the body does not absorb zinc from plant foods as well as from animal foods, so vegetarian diets tend to be low in it. Beans, nuts, seeds and fortified foods are plant sources. Zinc is in most multivitamins, so it can add up. MedlinePlus notes that a long-term excess intake of zinc can lead to copper, iron or magnesium deficiency. Our guide shows how to add up zinc and vitamin D across every product you take.

Iodine. "Humans need iodine for normal thyroid function, and for the production of thyroid hormones." MedlinePlus names iodized salt as the main food source, with seafood and dairy as other sources. Kelp, a sea vegetable, is also rich in iodine. A vegan diet leaves out seafood and dairy, so the salt you buy matters. When you buy salt, MedlinePlus says to make sure it is labeled "iodized." The adult RDA is 150 mcg a day. MedlinePlus notes that women who are pregnant or producing breast milk need higher amounts, and to ask your health care provider which amount is best for you. More is not better: MedlinePlus warns that very high iodine intake can reduce thyroid function, and that high doses taken with anti-thyroid medicines "can have an additive effect." If you have a thyroid condition, ask before adding a product with kelp or iodine.

Vitamin D and calcium: check the form, the source and the total

"Vitamin D helps the body absorb calcium." Your skin makes vitamin D in sunlight, but very few foods contain it naturally, so fortified foods such as some soy beverages, orange juice and cereals matter. Mushrooms provide some vitamin D, and MedlinePlus notes that mushrooms exposed to ultraviolet light have more. MedlinePlus's vitamin D page lists an RDA of 600 IU a day for adults 19 to 70 and 800 IU over 70, and an upper limit of 4,000 IU a day for adults and children 9 and older. It also notes that vitamin D toxicity almost always comes from taking too many supplements.

For calcium, MedlinePlus says "people on a vegan diet need to be sure to also include soy products and fortified products in order to get enough calcium." Leafy greens with oxalic acid, such as spinach, aren't counted as an adequate calcium source on their own because the body can't use much of their calcium. If you do use a supplement, calcium citrate "is taken up well by the body on a full or empty stomach."

If you take levothyroxine, MedlinePlus's levothyroxine page includes instructions about calcium and iron supplements. Ask your pharmacist how they apply to your prescription and your supplements.

Vegetarian vs. vegan: what changes if you eat eggs and dairy

MedlinePlus says vegetarian diets that include some dairy products and eggs "have all the nutrition you need." Eggs and dairy supply B12, dairy adds calcium and iodine, and egg yolks provide small amounts of vitamin D, so a lacto-ovo vegetarian usually has more options from food than a vegan does. Iron and zinc from plant foods are still absorbed less well, so those two are worth checking either way.

How to read a "vegan" supplement label

The FDA requires a Supplement Facts label listing every dietary ingredient and its amount per serving. For a vegan or vegetarian diet, look at these lines too:

Other ingredients. This is where the capsule material appears. Some softgels and capsules are made with gelatin, which MedlinePlus notes vegetarians don't eat. Plant-based capsules may be listed as hypromellose or "vegetable capsule."
Contains. Look for fish, shellfish, milk or eggs in the allergen line.
Source of vitamin D3. A label may list only "cholecalciferol" without saying where it comes from. If that matters to you, ask the maker.
Overlap. The same nutrient can appear in a multivitamin and a standalone product. The FDA notes problems can occur especially when people combine supplements or take too much of some supplements.

How VitOptics uses your diet answer

The VitOptics assessment asks for your diet style (Omnivore, Pescatarian, Vegetarian, Vegan or Other), how often you eat fish or seafood, your medications, your conditions, the supplements you already take and any allergies or ingredients you avoid. It also has an optional place to type in a recent lab result. Our personalized vitamin packs start from those answers. Automated checks review the recommendation; some profiles need additional review by a person on our team. A second automated check reads the whole pack before it is released.

Your result lists every formula, the amount of each ingredient and the reason it is there, so you can compare it with what you already take. Our catalogue includes an algal-oil omega-3 whose label lists no animal products. Not every formula has been confirmed as free of animal products yet.

Packs start from $59 a month, priced by what's in your pack and the same every month, with free standard U.S. shipping. VitOptics serves U.S. customers only.

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This article is for educational purposes and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease.

Prepared with AI assistance using the sources linked in this article.

Last updated: October 2026

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