What Nutrients Do Vegans Lack? A Guide to a Balanced Plant-Based Diet

November 12, 2025 •

4 min read

According to a study published in Nutrients, vegans often have lower intakes and blood levels of several key vitamins and minerals compared to omnivores. This guide explores exactly what nutrients do vegans lack and provides actionable strategies to build a complete, balanced plant-based diet.

Quick Summary

This article examines the key nutrients commonly lacking in a vegan diet, including vitamin B12, iron, calcium, vitamin D, iodine, and omega-3 fatty acids. It outlines dietary sources and supplementation strategies to ensure optimal health on a plant-based diet.

Key Points

Vitamin B12: Essential for nerve health, B12 is not found in plants. Supplementation or fortified foods are mandatory for vegans.
Iron: Plant-based non-heme iron is less absorbed than heme iron. Pair with vitamin C-rich foods to boost absorption.
Calcium & Vitamin D: Important for bone health. Vegans should seek fortified plant milks and consider Vitamin D supplements, especially during winter months.
Omega-3 Fatty Acids: EPA and DHA are limited in plant foods. Algae-based supplements are the most efficient source for vegans.
Iodine: Required for thyroid function, iodine can be deficient in vegan diets. Iodized salt or a supplement may be necessary.
Zinc: Found in legumes and nuts, but absorption can be inhibited by phytates. Soaking or sprouting can help.
Dietary Planning: A well-rounded and varied diet is crucial. Combining different plant foods can provide all necessary amino acids over the course of a day.

Essential Nutrients Vegans Need to Monitor

While a well-planned vegan diet can be healthful and nutritionally adequate, certain nutrients require careful attention due to their primary presence in animal products or lower bioavailability from plant sources. Understanding these potential gaps is the first step toward building a balanced and robust plant-based eating plan.

Vitamin B12

Vitamin B12 is arguably the most critical nutrient for vegans to monitor, as it is produced by bacteria and is not reliably found in plants. Natural food sources are limited to animal products, so a B12 supplement or fortified foods are essential for anyone following a vegan diet. Deficiency can lead to serious neurological damage and megaloblastic anemia. The Vegan Society and other health organizations emphasize that relying on unfortified plant foods for B12 is risky.

To ensure adequate B12 intake:

Fortified Foods: Regularly consume foods enriched with B12, such as nutritional yeast, plant milks, and breakfast cereals.
Supplements: The most reliable method is to take a daily B12 supplement.
Check Labels: Always check product labels, especially for fortified dairy alternatives, as fortification levels can vary.

Iron

Iron is crucial for red blood cell production and oxygen transport, and while many plant foods contain iron, the non-heme form found in plants is less easily absorbed by the body than the heme iron from meat. Vegans often have similar total iron intake as omnivores but may have lower iron stores.

Strategies to maximize iron absorption:

Pair with Vitamin C: Consume iron-rich foods with a source of vitamin C (e.g., bell peppers, oranges) to significantly increase absorption.
Soaking and Sprouting: Soaking, sprouting, or fermenting legumes and grains can reduce phytic acid, which inhibits iron absorption.
Avoid Inhibitors: Limit consumption of coffee and black tea with meals, as their tannins can decrease absorption.

Calcium

Calcium is vital for bone and teeth health, and while the stereotype is that vegans have poor bone density, a well-planned diet can provide sufficient amounts. However, lower calcium intake and status have been noted in some studies of plant-based diets.

Reliable vegan calcium sources include:

Calcium-Set Tofu: Tofu made with calcium sulfate is a rich source.
Fortified Plant Milks and Yogurts: Look for fortified varieties, checking the label to confirm.
Leafy Greens: Greens like kale, broccoli, and bok choy have high absorption rates.
Nuts and Seeds: Sesame seeds (tahini), almonds, and chia seeds are good options.

Vitamin D

Vitamin D is essential for calcium absorption and overall bone health. While sun exposure is the primary source, dietary intake can be low for everyone, not just vegans. Vegan food sources of D3 are limited, but fortified foods and supplements are reliable options.

Tips for obtaining Vitamin D:

Sun Exposure: Get safe, regular sun exposure during warmer months.
Fortified Foods: Incorporate fortified plant milks, cereals, and margarines into your diet.
Supplements: Many health organizations recommend a vitamin D supplement, especially in autumn and winter.

Omega-3 Fatty Acids

Omega-3 fatty acids, particularly EPA and DHA, are important for heart and brain health and are predominantly found in oily fish. While vegans can get ALA from plant foods, the conversion to EPA and DHA is inefficient.

Key vegan omega-3 sources:

ALA Sources: Include ground flaxseed, chia seeds, hemp seeds, and walnuts in your diet.
Algae Oil Supplements: Algae oil is a direct source of preformed EPA and DHA and is recommended for vegans to ensure adequate levels.

Iodine

Iodine is needed for thyroid hormone production, which regulates metabolism. Intake can be low in vegan diets, as dairy and fish are common sources in omnivorous diets.

To get enough iodine:

Iodized Salt: Use iodized salt for cooking, though many vegans prefer to limit salt intake.
Seaweed: Include moderate amounts of seaweed in your diet, but be mindful of excessive intake, which can also be harmful.
Fortified Products: Some plant milks are now fortified with iodine, so checking labels is important.

Comparison of Key Nutrients: Plant vs. Animal Sources

To understand the differences in bioavailability and sources, the following table compares key nutrients from typical vegan and omnivorous diets.


Nutrient	Primary Animal-Based Source	Primary Plant-Based Source	Bioavailability/Considerations
Vitamin B12	Meat, dairy, eggs	Fortified foods, supplements	Not reliably available in unfortified plant foods; supplementation is essential.
Iron	Red meat (heme iron)	Legumes, leafy greens, seeds (non-heme iron)	Non-heme iron absorption is lower; pair with vitamin C to enhance uptake.
Calcium	Dairy products	Fortified plant milks, tofu (calcium-set), kale	Absorption rates vary among plant sources; fortification is crucial for consistency.
Vitamin D	Oily fish, eggs, fortified dairy	Sun exposure, UV-exposed mushrooms, fortified foods	Synthesis from sunlight is most effective; vegan D3 from lichen is an option.
Omega-3s (EPA/DHA)	Oily fish	Algae oil (direct source); Flaxseed, chia seeds, walnuts (ALA)	Conversion from plant-based ALA is inefficient, making algae-based supplements ideal for EPA/DHA.
Iodine	Dairy, fish	Iodized salt, seaweed	Intake can be inconsistent; fortified plant milks or supplements may be needed.
Zinc	Meat, dairy, eggs	Legumes, nuts, seeds, whole grains	Phytates in plant foods can inhibit absorption; soaking and sprouting can help.

Conclusion: Navigating a Nutritionally Complete Vegan Diet

Adopting and maintaining a healthy vegan lifestyle is entirely achievable, but it requires mindful planning to address the nutrients traditionally sourced from animal products. By understanding which nutrients do vegans lack and where to find reliable plant-based sources, individuals can prevent potential deficiencies. The key takeaways are to prioritize a varied diet of whole plant foods, utilize fortified products consistently, and consider targeted supplementation for vital nutrients like vitamin B12, vitamin D, and EPA/DHA from algae. Regular health check-ups and blood tests can help monitor nutrient levels and ensure long-term health and well-being on a plant-based path. With proper education and a proactive approach, a vegan diet can provide all the necessary building blocks for a healthy life at any stage.

Frequently Asked Questions

The most critical supplement for a vegan is vitamin B12, as it is produced by bacteria and not reliably present in plant-based foods. Failure to supplement can lead to serious and irreversible neurological damage.

Vegans often consume similar or higher amounts of iron from plant sources compared to omnivores, but the iron is in the non-heme form, which is less readily absorbed by the body. This can sometimes result in lower iron stores, especially for menstruating women.

Vegans can get enough calcium from fortified plant milks and yogurts, calcium-set tofu, leafy greens like kale and bok choy, and various nuts and seeds such as tahini and almonds.

Many health experts recommend that everyone, including vegans, consider taking a vitamin D supplement, especially during the autumn and winter months, as sun exposure is the primary source and dietary sources are limited.

Vegans can get ALA Omega-3s from flaxseed, chia seeds, and walnuts. For the more bioavailable EPA and DHA, an algae-based supplement is the most efficient and direct source, as the body's conversion of ALA is inefficient.

Good sources of vegan protein include a variety of legumes (beans, lentils, peas), nuts, seeds, whole grains, and soy products like tofu and tempeh. Consuming a variety of these sources throughout the day ensures all essential amino acids are acquired.

To improve nutrient absorption, vegans can pair iron-rich foods with vitamin C sources, soak or sprout legumes and nuts to reduce phytic acid, and limit tea or coffee consumption with meals.