What micronutrients may vegans be deficient in? A Guide to Nutrient-Dense Vegan Diets

October 29, 2025 •

5 min read

According to a 2021 review of 48 studies, vegan diets are often associated with lower intakes of several key micronutrients, including vitamin B12, vitamin D, iodine, zinc, and calcium. Knowing what micronutrients may vegans be deficient in is crucial for maintaining a balanced and healthy plant-based lifestyle that avoids common pitfalls.

Quick Summary

A well-planned vegan diet can be healthy, but it requires special attention to specific micronutrients. This article details the nutrients most commonly at risk, explains why they are problematic for vegans, and outlines effective strategies involving fortified foods and supplements to ensure nutritional adequacy.

Key Points

Vitamin B12 is essential for all vegans: As it is not reliably available from plants, a supplement or fortified foods are a must to prevent irreversible nerve damage.
Enhance iron absorption strategically: Pair plant-based, non-heme iron sources with vitamin C to significantly improve absorption. Avoid drinking coffee or tea with iron-rich meals.
Prioritize calcium and vitamin D for bone health: Fortified plant milks and calcium-set tofu are excellent sources, while a supplement is often recommended for vitamin D, especially in winter.
Address iodine needs with fortified salt or supplements: Since iodine content in plants is inconsistent, relying on iodized salt or an iodine-containing supplement is the safest strategy.
Optimize zinc intake and bioavailability: Include a variety of zinc-rich foods and consider sprouting grains and legumes to reduce phytate inhibitors. Supplements can help if dietary intake is insufficient.
Supplement with algae-based omega-3s: To ensure adequate levels of DHA and EPA for brain and heart health, an algae oil supplement is the most reliable vegan source.
Regular monitoring is a proactive health measure: Consulting a healthcare provider or dietitian and getting periodic blood tests can help confirm that all nutrient needs are being met.

Common Micronutrient Concerns for Vegans

While a vegan diet is rich in many vitamins, fiber, and phytochemicals, the exclusion of all animal products means certain micronutrients must be carefully managed. Below are some of the most critical nutrients to monitor on a plant-based diet.

Vitamin B12

Vitamin B12 is arguably the most crucial supplement for any vegan. It is produced by microorganisms and is not reliably present in plant foods. The human body stores vitamin B12, so a deficiency can take years to develop, but once depleted, it can cause severe health issues.

Why it's a concern: Vitamin B12 is almost exclusively found in animal products like meat, eggs, and dairy. Even farmed animals are often given B12 supplements, making the animal product a secondary source.
Consequences of deficiency: A lack of B12 can lead to megaloblastic anemia, fatigue, nerve damage, tingling in the hands and feet, memory problems, and other neurological disorders.
Solution: Fortified foods (plant milks, cereals, nutritional yeast) and consistent supplementation are necessary. The Vegan Society recommends daily B12 supplements of at least 10 mcg or weekly doses of 2000 mcg.

Iron

Although plant-based diets can be high in iron, the type found in plants (non-heme iron) is less readily absorbed by the body than the heme iron found in animal sources.

Why it's a concern: Non-heme iron absorption is inhibited by compounds like phytates and tannins, found in many plant foods such as legumes, whole grains, nuts, and seeds.
Consequences of deficiency: Iron deficiency can cause fatigue, weakness, pale skin, headaches, and in severe cases, iron-deficiency anemia.
Solution: Vegans can boost non-heme iron absorption by pairing iron-rich plant foods with sources of vitamin C (e.g., citrus fruits, bell peppers, tomatoes). Soaking and sprouting legumes and grains also helps reduce phytate levels.

Calcium

With dairy products removed, vegans must focus on alternative sources to maintain strong bones and proper physiological function.

Why it's a concern: Dairy is a primary source of calcium in omnivorous diets. Plant-based sources of calcium can be hindered by oxalates and phytates, which reduce bioavailability.
Consequences of deficiency: Low calcium intake can increase the risk of osteoporosis and fractures, especially in later life.
Solution: Incorporate calcium-fortified plant milks and yogurts, calcium-set tofu, and low-oxalate green leafy vegetables like kale and broccoli.

Vitamin D

Vitamin D is essential for calcium absorption and bone health. While sunlight is the main source, dietary intake is important, particularly during winter months or for those with limited sun exposure.

Why it's a concern: Dietary sources of vitamin D are mostly limited to fortified foods and some mushrooms. Without dairy and fatty fish, vegans' dietary vitamin D intake can be low.
Consequences of deficiency: Deficiency can lead to bone-softening conditions like rickets in children and osteomalacia in adults.
Solution: Fortified plant milks, cereals, and margarine are good options. Many vegans also need to take a daily vitamin D supplement.

Iodine

Iodine is critical for thyroid function, and its presence in plant foods is highly variable depending on soil content.

Why it's a concern: Dairy and seafood are significant iodine sources. Without these, vegans are at risk, especially if they do not use iodized salt.
Consequences of deficiency: Iodine deficiency can lead to hypothyroidism, causing fatigue, weight gain, and goiter. In pregnant women, it can harm fetal brain development.
Solution: Use iodized salt in moderation and consider a daily supplement. Seaweed can be a source, but iodine levels vary greatly, and excessive intake can also be harmful.

Zinc

Zinc absorption from plant sources is lower than from animal sources due to phytic acid.

Why it's a concern: Phytates in whole grains, legumes, and nuts bind to zinc, reducing its absorption.
Consequences of deficiency: Zinc deficiency can impair immune function, wound healing, and growth.
Solution: Include zinc-rich foods like legumes, nuts, seeds, and whole grains, and use techniques like soaking, sprouting, and fermentation to improve absorption. Some vegans may benefit from a supplement.

Omega-3 Fatty Acids (EPA and DHA)

Long-chain omega-3s, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are most commonly found in fatty fish. While plant sources contain the shorter-chain alpha-linolenic acid (ALA), the body's conversion to EPA and DHA is inefficient.

Why it's a concern: The primary sources of EPA and DHA are not vegan. Vegans rely on ALA from seeds, nuts, and oils for conversion, but the process is not very effective.
Consequences of deficiency: Low levels of EPA and DHA can affect brain and eye health and may increase the risk of heart disease.
Solution: Supplementation with algae-based omega-3 oil provides a direct source of EPA and DHA. Ground flaxseeds, chia seeds, and walnuts are good sources of ALA.

Comparison of Key Vegan Micronutrient Strategies


Micronutrient	Primary Concern for Vegans	Good Vegan Food Sources	How to Maximize Intake	Supplementation Strategy
Vitamin B12	Not reliably found in plants.	Fortified plant milks, cereals, and nutritional yeast.	Ensure consistent daily or weekly intake from fortified foods.	Essential: Take a B12 supplement regularly.
Iron	Non-heme iron is less bioavailable.	Legumes, whole grains, nuts, seeds, dark leafy greens.	Pair with vitamin C-rich foods; soak and sprout grains/legumes.	Typically not required if diet is well-planned, but may be needed for some women.
Calcium	Lower intake and reduced bioavailability from some plants.	Fortified plant milks, calcium-set tofu, kale, broccoli.	Avoid high-oxalate foods with calcium-rich meals; choose fortified products.	Can be helpful, especially if intake is low.
Vitamin D	Limited dietary sources without fortification.	Fortified milks/cereals, some UV-grown mushrooms.	Get safe sun exposure and include fortified foods.	Recommended, especially in winter or for those with low sun exposure.
Iodine	Content in plants varies; lack of dairy/seafood sources.	Iodized salt, seaweed (in moderation).	Use iodized salt and/or supplements. Avoid excess seaweed.	Recommended for those not using iodized salt or as part of a general multivitamin.
Zinc	Absorption is reduced by phytates in plant foods.	Legumes, seeds, nuts, whole grains.	Use soaking, sprouting, and fermentation; include a variety of sources.	Consider a modest supplement if symptoms arise or absorption is a concern.
Omega-3s (DHA/EPA)	Inefficient conversion from plant-based ALA.	Flaxseeds, chia seeds, walnuts (ALA).	Include ALA sources daily; use an algae-based supplement for direct DHA/EPA.	Recommended to ensure adequate intake of EPA and DHA.

Conclusion

For individuals on a vegan diet, acknowledging and addressing potential micronutrient deficiencies is key to long-term health and wellness. The risks associated with deficiencies in nutrients like vitamin B12, vitamin D, iron, calcium, iodine, zinc, and omega-3s can be effectively managed with informed dietary planning. This involves prioritizing a variety of whole plant foods, incorporating fortified products, and regularly using supplements for nutrients that are difficult to obtain from plant sources, most notably vitamin B12. Consulting a registered dietitian can provide personalized guidance and ensure all nutritional needs are met. With proper planning, a vegan diet can be a sustainable and health-promoting choice.

For more in-depth information and resources on vegan nutrition, visit the reliable guides from organizations like the Vegan Society.

Frequently Asked Questions

Vitamin B12 is produced by microorganisms, not plants, and is found in animal products. Since vegans exclude all animal-derived foods, a consistent and reliable source from supplements or fortified foods is essential to prevent deficiency and irreversible nerve damage.

To improve absorption of non-heme iron from plants, pair iron-rich foods with a source of vitamin C, such as citrus fruits, tomatoes, or bell peppers. Soaking and sprouting legumes and grains also helps to reduce phytates, which can inhibit iron absorption.

Excellent vegan calcium sources include fortified plant milks (e.g., almond, soy, oat milk), calcium-set tofu, and certain green leafy vegetables like kale and broccoli. It's important to choose fortified products to ensure sufficient intake.

Fortified foods can provide a significant portion of several key nutrients like vitamin B12, calcium, and vitamin D. However, relying solely on them can be unreliable. Supplements are often necessary to ensure consistent and adequate intake, especially for vitamin B12 and potentially iodine or omega-3s.

While some vitamin D can be obtained from fortified foods and UV-exposed mushrooms, the primary source is sunlight. Vegans with limited sun exposure, or during winter, should consider a vitamin D supplement to maintain healthy levels.

Good vegan sources of zinc include legumes (lentils, chickpeas), nuts (cashews, almonds), seeds (pumpkin, sesame), whole grains, and tofu. Soaking and sprouting can improve zinc absorption from these foods.

Since the conversion of plant-based ALA to the longer-chain EPA and DHA is inefficient, many vegans benefit from an omega-3 supplement derived from algae. This provides a direct and reliable source of EPA and DHA for brain and cardiovascular health.