What nutrients may be of concern, especially for vegans?

October 28, 2025 •

4 min read

According to a systematic review, vegans are typically associated with lower intakes of several nutrients, including vitamin B12, vitamin D, iodine, and zinc. Understanding what nutrients may be of concern, especially for vegans, is crucial for anyone adopting or maintaining a plant-based diet to ensure nutritional adequacy and long-term health. With proper planning and supplementation, a vegan diet can be nutritionally sufficient.

Quick Summary

A comprehensive guide to nutrients requiring special attention on a vegan diet, such as vitamin B12, iron, calcium, vitamin D, omega-3s, iodine, and zinc. Includes tips on food sources, absorption strategies, and supplementation to prevent deficiencies and maintain a balanced, healthy plant-based lifestyle.

Key Points

Vitamin B12 is essential for vegans: Since B12 is not reliably found in plant foods, all vegans need a supplement or regular fortified foods to prevent nerve damage and anemia.
Pair iron with vitamin C: To combat the lower bioavailability of non-heme iron from plants, combine iron-rich foods with vitamin C sources to boost absorption.
Choose fortified and high-calcium sources: Focus on fortified plant milks and calcium-set tofu, as some leafy greens like spinach contain oxalates that interfere with calcium absorption.
Consider supplements for Vitamin D and Omega-3s: For consistent intake, particularly in colder climates, supplements for vitamin D and algae-based omega-3s (EPA/DHA) are highly recommended, typically as advised by a healthcare professional.
Ensure reliable iodine and zinc sources: Rely on iodized salt or supplements for iodine, and use soaking or sprouting techniques to reduce phytates and enhance zinc absorption from legumes and grains.

A well-planned vegan diet can provide numerous health benefits and be nutritionally sufficient. However, eliminating all animal products requires careful attention to key nutrients that are either absent or have lower bioavailability in plant-based foods. By focusing on fortified foods and strategic supplementation, vegans can thrive and avoid potential deficiencies.

Vitamin B12: The Most Critical Concern

Vitamin B12 is arguably the most important nutrient for vegans to monitor, as it is not reliably found in unfortified plant foods. B12 is essential for nerve function and red blood cell formation, and a deficiency can lead to anemia and severe, irreversible neurological damage. While some plant foods like certain fermented products or seaweed may contain minimal B12, these are not considered reliable sources. Therefore, supplementation is necessary for all vegans.

Sources: Fortified foods are an option, including fortified breakfast cereals, nutritional yeast, and plant-based milks.
Strategy: The most reliable method is taking a B12 supplement as directed by a healthcare professional.

Iron: Maximizing Absorption from Plant Sources

Plant-based iron is non-heme iron, which is not as readily absorbed by the body as the heme iron found in meat. While vegans are not necessarily more prone to iron-deficiency anemia than meat-eaters, a well-planned strategy is needed to maximize absorption.

Sources: Lentils, chickpeas, beans, tofu, tempeh, dark leafy greens (like kale and spinach), dried fruits, and pumpkin seeds are excellent plant-based sources.
Strategy: To enhance absorption, pair iron-rich foods with a source of vitamin C, like bell peppers, citrus fruits, or strawberries. Avoid drinking coffee or tea around mealtimes, as their compounds can inhibit absorption.

Calcium: Strong Bones Without Dairy

Calcium is vital for bone health, and while dairy is a common source, vegans can get plenty from plant-based options. However, some plant sources, like spinach, contain oxalates that bind to calcium and reduce its bioavailability.

Sources: Fortified plant milks (e.g., soy, almond, oat), calcium-set tofu, collard greens, almonds, and tahini are great choices.
Strategy: Opt for fortified products and be mindful that some leafy greens offer less available calcium than others. Regular intake from a variety of sources is key.

Vitamin D: Sunlight and Supplements

Vitamin D is necessary for calcium absorption and overall bone health. The body can produce it from sun exposure, but many vegans still have low levels, especially in regions with limited sunlight or during winter.

Sources: Mushrooms exposed to UV light are one of the few natural vegan food sources. Many plant milks and cereals are fortified with vitamin D.
Strategy: Regular, safe sun exposure is beneficial. However, a vitamin D supplement, taken as advised by a healthcare professional, is often recommended to ensure adequate intake, particularly for those with limited sun exposure.

Omega-3 Fatty Acids: From Algae to Seeds

Omega-3s, particularly EPA and DHA, are crucial for brain, eye, and heart health. The body can convert alpha-linolenic acid (ALA), found in many plant foods, into EPA and DHA, but this conversion is often inefficient.

Sources: Walnuts, flaxseeds, chia seeds, and hemp seeds provide ALA. Algae-based supplements are excellent direct sources of EPA and DHA.
Strategy: Include ALA-rich foods daily and consider a high-quality microalgae supplement for a reliable source of preformed EPA and DHA, as recommended by a healthcare professional.

Iodine: The Importance of a Reliable Source

Iodine is essential for thyroid function. The iodine content of plants is highly variable and depends on the soil they are grown in.

Sources: Iodized salt is a common source, though intake should be moderate. Seaweed is a very rich source, but iodine levels vary greatly and can be excessive.
Strategy: Using iodized salt in moderation is a straightforward approach. Alternatively, a supplement, taken as directed, is the most reliable way to ensure a consistent intake.

Zinc: Counteracting the Effects of Phytates

Zinc is important for immune function, protein metabolism, and cell growth. Plant-based sources contain phytates, which can inhibit zinc absorption.

Sources: Legumes, whole grains, nuts, and seeds are good sources. Tofu, tempeh, and fortified breakfast cereals also provide zinc.
Strategy: Soaking, sprouting, or fermenting foods can help reduce phytates and improve zinc absorption.

Comparison of Key Nutrients for Vegans


Nutrient	Primary Challenge for Vegans	Key Plant-Based Food Sources	Supplementation Need
Vitamin B12	Not naturally found in plant foods.	Fortified foods (cereals, plant milks), nutritional yeast.	Essential for all vegans, typically through supplementation.
Iron	Non-heme iron is less bioavailable than heme iron from meat.	Lentils, chickpeas, tofu, dark leafy greens, pumpkin seeds.	Usually not needed with careful planning and vitamin C pairing.
Calcium	Excluding dairy, and some plant sources have low bioavailability.	Fortified plant milks, calcium-set tofu, collard greens, almonds.	May be beneficial depending on dietary intake.
Vitamin D	Limited food sources, and sunlight exposure varies.	UV-exposed mushrooms, fortified foods.	Often recommended, especially in winter or with low sun exposure.
Omega-3s	Inefficient conversion of ALA to EPA/DHA.	Walnuts, flaxseeds, chia seeds, algae oil.	Algae-based EPA/DHA supplement often recommended.
Iodine	Inconsistent levels in plant foods depending on soil quality.	Iodized salt, seaweed (use with caution).	Recommended for consistent intake, particularly for pregnant/breastfeeding individuals.
Zinc	Presence of phytates in plant foods inhibits absorption.	Legumes, whole grains, nuts, seeds, tofu.	May be beneficial; phytate reduction techniques can help.

Conclusion

While a vegan diet offers many health advantages, it requires diligent planning to avoid deficiencies in several key nutrients. Vitamin B12 is non-negotiable for supplementation, while others like vitamin D, omega-3s, and iodine are often recommended for consistent and optimal intake, typically as advised by a healthcare professional. For iron and zinc, strategic food pairings and preparation techniques can significantly improve absorption. Ultimately, understanding these nutritional considerations empowers individuals to build a robust and well-rounded plant-based eating plan.

For more information on balancing a vegan diet, visit The Vegan Society's nutrition resources.

Frequently Asked Questions

Vitamin B12 is produced by bacteria and is found almost exclusively in animal products. Since it is not reliably available from unfortified plant foods, supplements, as advised by a healthcare professional, are necessary to prevent serious neurological and hematological issues.

To maximize iron absorption, pair plant-based iron sources, like lentils and spinach, with foods high in vitamin C, such as bell peppers or citrus fruits. Avoiding coffee or tea around mealtimes also helps.

Besides fortified plant milks, excellent vegan sources of calcium include calcium-set tofu, collard greens, almonds, and tahini. It is important to note that the calcium in some leafy greens, like spinach, is not as well-absorbed due to compounds called oxalates.

A well-planned vegan diet can easily meet protein recommendations. Including a variety of protein-rich plant foods like legumes, tofu, tempeh, and whole grains throughout the day is sufficient.

While walnuts, flaxseeds, and chia seeds provide ALA, a less efficiently converted omega-3, a microalgae-based supplement, as recommended by a healthcare professional, is the most reliable vegan source for EPA and DHA, which are crucial for brain and heart health.

Yes, iodine is a concern for vegans because its content in plant foods is inconsistent and depends on the soil. Relying on iodized salt or taking a supplement, as advised by a healthcare professional, is the most effective way to ensure adequate intake.

Phytates in plant foods can inhibit zinc absorption. To improve it, use techniques like soaking, sprouting, or fermenting legumes and grains. Regular consumption of zinc-rich foods like beans, nuts, and seeds is also important.