Why are vegans at risk for iron deficiency?

October 29, 2025 •

4 min read

Studies consistently show that individuals following vegan diets tend to have lower iron stores compared to omnivores. This occurs primarily because plant-based iron, known as non-heme iron, is not as readily absorbed by the body as the heme iron found in meat and other animal products.

Quick Summary

Understand the critical differences between heme and non-heme iron and the dietary factors inhibiting absorption in a vegan diet. Learn how to strategically combine plant-based foods to enhance iron intake and minimize deficiency risks.

Key Points

Heme vs. Non-Heme Iron: Vegans consume non-heme iron, which is less bioavailable than the heme iron found in animal products, requiring higher intake and strategic meal planning.
Absorption Inhibitors: Compounds like phytates in grains and legumes, and polyphenols in coffee and tea, can block non-heme iron absorption.
Enhancers are Key: Pairing iron-rich plant foods with sources of Vitamin C dramatically improves non-heme iron absorption.
Cooking with Cast Iron: Using a cast iron skillet can naturally boost the iron content of your meals, a useful hack for increasing your intake.
Listen to Your Body: Fatigue, weakness, and pale skin are common symptoms of low iron, signaling the need for dietary adjustments or medical advice.

Understanding Heme vs. Non-Heme Iron

Iron is an essential mineral vital for producing hemoglobin, the protein in red blood cells that transports oxygen throughout the body. For those on a plant-based diet, understanding the two types of dietary iron is crucial for maintaining adequate levels. Iron comes in two forms: heme and non-heme.

The Challenge of Non-Heme Iron Absorption

Heme iron is found exclusively in animal flesh, such as meat, poultry, and seafood, and is significantly more bioavailable, with absorption rates of up to 30%. Non-heme iron, by contrast, is found in plant foods and is less efficiently absorbed by the body, typically at a rate of 2% to 10%. The lower absorption rate of non-heme iron is a primary reason why vegans are at risk for iron deficiency.

Factors Inhibiting Iron Absorption

Several common plant compounds can further inhibit the absorption of non-heme iron. These include:

Phytates: Found in whole grains, legumes, seeds, and nuts, phytates can bind to non-heme iron and interfere with its absorption. Soaking, sprouting, or fermenting these foods can help reduce their phytate content.
Polyphenols: These compounds are present in coffee, tea, cocoa, and some spices. They can significantly reduce iron absorption, so it is recommended to consume these beverages separately from iron-rich meals.
Calcium: While essential, calcium can also inhibit the absorption of both non-heme and heme iron. For this reason, calcium supplements are best taken between meals, not with them.

Strategies for Maximizing Iron Absorption on a Vegan Diet

Fortunately, there are several simple and effective strategies for maximizing non-heme iron absorption.

Pairing with Vitamin C

One of the most effective methods is to combine iron-rich plant foods with foods high in vitamin C (ascorbic acid). Vitamin C helps convert non-heme iron into a more readily absorbed form. For example, adding citrus juice to a lentil salad or bell peppers to a black bean burrito can dramatically increase iron uptake.

Cooking with Cast Iron

Cooking in a cast iron skillet can significantly increase the iron content of your food, especially when preparing acidic foods like tomato sauce. This is a simple and effective hack for boosting dietary iron over time.

The Importance of Soaking and Sprouting

To reduce phytates in legumes, grains, nuts, and seeds, soaking them in water for several hours before cooking is highly beneficial. For example, soaking chickpeas before making hummus or sprouting lentils for a salad can improve their iron bioavailability.

Comparison of Iron Types


Feature	Heme Iron	Non-Heme Iron
Source	Animal products (meat, poultry, fish)	Plant products (legumes, grains, greens) and fortified foods
Bioavailability	High (15-30%)	Low (2-10%)
Absorption Inhibitors	Minimal; less affected by dietary factors	Inhibited by phytates, polyphenols, and calcium
Absorption Enhancers	Not significantly affected	Enhanced by vitamin C and beta-carotene
Risk of Deficiency	Lower risk for omnivores	Higher risk for vegans without careful planning

Common Symptoms of Iron Deficiency

Without proper planning, a vegan diet can lead to iron deficiency and, eventually, iron deficiency anemia. Symptoms often start mild and can worsen over time.

Fatigue and Weakness: Extreme tiredness and lack of energy are common due to insufficient oxygen transport.
Pale Skin: Reduced hemoglobin levels can cause the skin to appear paler than usual.
Shortness of Breath: The body struggles to deliver enough oxygen, leading to breathlessness during activity.
Headaches and Dizziness: Insufficient oxygen flow to the brain can cause headaches and lightheadedness.
Brittle Nails: Nails may become brittle, or even spoon-shaped (koilonychia) in severe cases.
Cravings: Pica, or the craving for non-food items like ice or dirt, can occur with severe deficiency.

Conclusion

While it is true that non-heme iron from plant sources is less bioavailable than heme iron, this does not mean that vegans are destined for deficiency. By understanding the mechanisms behind iron absorption and strategically pairing iron-rich foods with enhancers like vitamin C, vegans can ensure they get all the iron they need. Proper meal planning, including techniques like soaking and sprouting, is key to overcoming the challenges of a purely plant-based diet. Regular monitoring of iron levels, especially for women of reproductive age, is a prudent step to ensure long-term health and well-being.

For more detailed dietary strategies and tips on maintaining optimal health on a plant-based diet, consult resources from organizations like The Vegan Society, which provides excellent nutritional guidelines. You can explore their extensive resources on iron and other key nutrients here: Iron | The Vegan Society.

Key Vegan Iron Sources

Legumes: Lentils, chickpeas, black beans, and kidney beans are excellent sources of non-heme iron. A single cup of cooked lentils provides a significant amount of iron.
Tofu and Tempeh: These soy products are not only rich in protein but also contain good amounts of iron.
Nuts and Seeds: Pumpkin seeds, sesame seeds, cashews, and hemp seeds are all great sources of iron. Snacking on a handful or adding them to meals can boost your intake.
Fortified Grains: Many breakfast cereals, breads, and plant-based milks are fortified with iron. Always check the nutrition labels.
Dark, Leafy Greens: While the bioavailability can be affected by oxalates, greens like kale and cooked spinach still contribute valuable iron to your diet, especially when paired with vitamin C.
Dried Fruit: Raisins, dried apricots, and dates offer a good dose of iron and are easy to incorporate into snacks.
Mushrooms: Some mushroom varieties, like white button mushrooms, can contribute to your iron intake.
Blackstrap Molasses: A spoonful of this byproduct of sugar production is a surprisingly potent source of non-heme iron.

Frequently Asked Questions

Yes, a well-planned vegan diet can provide enough iron. Vegans primarily consume non-heme iron from plant sources, which is less absorbed than heme iron. However, by eating a variety of iron-rich foods and using absorption-enhancing strategies, it is possible to meet iron needs.

Heme iron is found only in animal products and is highly bioavailable. Non-heme iron is found in plant foods and is less easily absorbed by the body. Vegans rely entirely on non-heme iron.

Excellent vegan sources of non-heme iron include lentils, chickpeas, tofu, tempeh, beans, seeds (like pumpkin and sesame), whole grains, dried fruits, and dark, leafy greens.

Certain compounds inhibit non-heme iron absorption, including phytates in grains and legumes, and polyphenols in coffee and tea. Calcium can also interfere with absorption.

To improve absorption, pair iron-rich plant foods with foods high in vitamin C, such as citrus fruits, bell peppers, or broccoli. Soaking legumes and grains also helps reduce absorption-inhibiting phytates.

Initial symptoms of iron deficiency can include fatigue, weakness, and pale skin. As it progresses, you might experience shortness of breath, headaches, dizziness, and brittle nails.

For most healthy vegans, routine supplementation is not necessary, but those at higher risk, such as pregnant women or individuals with a history of deficiency, should consider a supplement. Always consult a healthcare provider before beginning supplementation.

Yes, cooking acidic foods in a cast-iron skillet can increase the iron content of your meals. This is a simple and effective way to get a little extra iron.

While spinach contains iron, it also contains oxalates that can inhibit iron absorption, so it's not as effective as once thought. However, when consumed with vitamin C, it can still be a valuable part of a balanced diet.