Understanding What Nutrient Deficiency Can Vegans Be at Risk For

November 27, 2025 •

4 min read

According to a 2021 review, following a vegan diet may result in deficiencies in several key micronutrients, such as vitamin B12, zinc, and calcium. Being aware of what nutrient deficiency can vegans be at risk for is the first step toward proactive health management on a plant-based diet.

Quick Summary

A well-planned vegan diet is essential to avoid nutritional shortfalls in key vitamins and minerals. Particular attention is required for vitamin B12, iron, calcium, and omega-3 fatty acids. These can be managed through fortified foods, strategic food pairings, and appropriate supplementation.

Key Points

Vitamin B12: A supplement or fortified foods are essential, as B12 is not reliably found in plant sources and deficiency can lead to serious neurological issues.
Iron: The non-heme iron in plants is less absorbed, so pair iron-rich foods like lentils with vitamin C sources to boost uptake.
Calcium: Rely on calcium-set tofu, fortified plant milks, and low-oxalate greens like kale to meet your daily needs without dairy.
Vitamin D: Fortified foods and supplements are necessary, especially in winter, to support calcium absorption and overall bone health.
Omega-3s: Since the body's conversion of plant-based ALA to EPA/DHA is inefficient, consider a direct algae-based supplement for these essential fatty acids.
Iodine and Zinc: Use iodized salt for iodine and ensure consistent intake of nuts, seeds, and legumes for zinc.
Regular Monitoring: Periodic blood tests can help ensure your nutrient levels remain optimal and prevent deficiencies.

Essential Nutrients Requiring Attention

While a balanced vegan diet can be rich in fiber, vitamins, and antioxidants, it eliminates primary sources of certain nutrients found predominantly in animal products. Careful planning is therefore crucial to ensure adequate intake of the following.

Vitamin B12: The Most Critical Concern

Vitamin B12 is arguably the most important nutrient for vegans to monitor, as it is not reliably available from plant-based foods. It is vital for nerve function, red blood cell production, and DNA synthesis. A deficiency can lead to serious neurological issues and anemia. Fortified foods and supplements are the only proven reliable sources of vitamin B12 for vegans.

Fortified foods: Look for breakfast cereals, nutritional yeast, and plant milks that are clearly labeled as fortified with vitamin B12.
Supplements: The Vegan Society recommends either eating fortified foods two to three times a day to get at least 3 mcg of B12, taking a daily supplement of at least 10 mcg, or a weekly supplement of at least 2000 mcg.

Iron: Mindful Absorption is Key

While many plant foods are good sources of iron, the non-heme iron found in plants is less easily absorbed by the body than the heme iron from meat. Vegans, particularly women, need to employ strategies to enhance absorption.

Plant sources: Lentils, chickpeas, dark leafy greens, tofu, nuts, and fortified cereals are excellent sources.
Boosting absorption: Pair iron-rich foods with a source of vitamin C, such as citrus fruits, bell peppers, or broccoli. Avoid drinking coffee or tea within an hour of an iron-rich meal, as they can inhibit absorption.

Calcium and Vitamin D: The Bone Health Duo

Calcium is essential for strong bones and teeth, while vitamin D helps the body absorb calcium. Vegans consume no dairy products, a major source of calcium in Western diets, and may have lower intakes. Sunlight exposure can provide vitamin D, but geographical location and season can limit this.

Calcium sources: Excellent plant-based options include calcium-set tofu, fortified plant milks and yogurts, and low-oxalate leafy greens like kale and bok choy.
Vitamin D sources: Fortified plant milks, certain mushrooms exposed to UV light, and supplements are necessary, especially during winter months.

Omega-3 Fatty Acids: ALA Conversion and Supplementation

Omega-3 fatty acids, crucial for brain and heart health, come in three main forms: ALA, EPA, and DHA. The primary plant-based omega-3 is ALA, which the body can convert into EPA and DHA, but often inefficiently.

ALA sources: Flaxseeds, chia seeds, hemp seeds, and walnuts are rich in ALA.
Direct DHA/EPA: Algae-based supplements are a reliable way for vegans to get direct sources of EPA and DHA.

Iodine and Zinc: Essential Minerals

Iodine is critical for thyroid function, while zinc is vital for immune health and metabolism. Vegans may have lower intakes of both.

Iodine sources: Iodized salt and seaweed with moderate iodine content are reliable sources.
Zinc sources: Legumes, nuts, seeds, and whole grains contain zinc, but bioavailability can be affected by phytates. Soaking and sprouting can help improve absorption.

Comparison of Nutrient Bioavailability

Some plant-based nutrients are less bioavailable than their animal-sourced counterparts. The table below compares the absorption dynamics of key nutrients for vegans versus omnivores.


Nutrient	Vegan Source Bioavailability	Omnivore Source Bioavailability
Vitamin B12	Not naturally present; must come from fortified foods or supplements.	Readily available and absorbed from meat, fish, and dairy.
Iron	Non-heme iron, which is less easily absorbed. Absorption is boosted by vitamin C.	Heme iron, which is highly bioavailable.
Calcium	Absorption is sometimes hindered by oxalates and phytates in plants. Fortified sources have higher bioavailability.	Readily available and highly absorbed from dairy products.
Zinc	Absorption can be inhibited by phytic acid in whole grains and legumes.	More easily absorbed from animal proteins.

Strategies for a Nutrient-Complete Vegan Diet

Achieving nutritional adequacy on a vegan diet is highly achievable with proper knowledge and planning. The key is to be intentional with your food choices and understand the role of supplementation.

Diversify your plate: Incorporate a wide variety of whole plant foods, including different types of fruits, vegetables, legumes, nuts, and seeds. This helps ensure a broad spectrum of nutrients.
Use fortified foods strategically: Rely on fortified plant milks, breakfast cereals, and nutritional yeast for daily intake of B12, D, and calcium. Check labels carefully to ensure adequate fortification.
Master food pairing: Always pair iron-rich meals with a source of vitamin C to maximize absorption. For example, add citrus dressing to a lentil salad or include bell peppers in your chili.
Consider targeted supplements: For non-negotiable nutrients like B12, a supplement is the most reliable option. For DHA/EPA, an algae-based supplement can cover any gaps in conversion.
Consult a professional: Consider speaking with a registered dietitian or doctor, especially when pregnant, breastfeeding, or if you have specific health concerns. Regular blood tests can help monitor your nutrient levels.

Conclusion

While a vegan diet can offer numerous health benefits, such as a lower risk of chronic diseases, it does require deliberate attention to certain nutrients. Foremost among these is vitamin B12, which mandates supplementation or consistent consumption of fortified foods. Other key areas include optimizing iron absorption and ensuring adequate intake of calcium, vitamin D, and omega-3 fatty acids through strategic food choices and targeted supplementation. With proper planning, a vegan diet can be nutritionally adequate and promote long-term health. Resources like the Vegan Society's nutrition guide can provide further information and support for a healthy plant-based journey.(https://www.vegansociety.com/resources/nutrition-and-health/nutrients/vitamin-b12/what-every-vegan-should-know-about-vitamin-b12)

Frequently Asked Questions

Vitamin B12 is the most critical nutrient for vegans to supplement, as it is not naturally present in plant-based foods. Consistent intake of a supplement or fortified foods is necessary to prevent deficiency.

Yes, a well-planned vegan diet can provide sufficient iron. However, since plant-based iron is less bioavailable, it is important to enhance absorption by consuming iron-rich foods with vitamin C at the same meal.

Good vegan sources of calcium include calcium-set tofu, fortified plant milks and yogurts, and low-oxalate leafy greens like kale and bok choy. Fortified products are particularly effective for consistent intake.

The body's conversion of the plant-based omega-3 (ALA) into the active forms (EPA and DHA) can be inefficient. While ALA is found in flax and chia seeds, an algae-based supplement provides a direct source of EPA and DHA.

While supplementation for vitamin B12 is considered a must, others like vitamin D, calcium, and omega-3s can often be obtained through fortified foods and a varied diet. Personalized needs should be discussed with a healthcare provider.

To improve zinc absorption from plant sources like legumes and grains, methods like soaking and sprouting can be used to reduce phytates, which inhibit absorption.

A poorly planned vegan diet can lead to deficiencies in key nutrients like vitamin B12, iron, and calcium, potentially causing health issues such as anemia, osteoporosis, and neurological disorders.