Iron deficiency on a vegan or vegetarian diet
Eating plant-based does not automatically mean deficiency. But your body gets iron from plants differently than from meat. What that means in practice, which levers exist and what you can pay attention to.
Plant iron is absorbed less well than iron from meat. That is the core that everything revolves around. Vegans and vegetarians have lower iron stores on average and therefore a higher risk of deficiency. That does not mean they have a deficiency, though. With a few levers in how you put meals together, absorption can be noticeably improved.
In my practice I often sit with people who eat plant-based in a thoughtful, deliberate way and still wonder why they are tired all the time. Eating plant-based is not a mistake. It only asks you to understand one detail that classic nutrition advice sometimes underplays: what counts is not how much iron sits on the plate, but how much of it reaches your body.
Heme and non-heme iron: two different doors
Many people who avoid meat know the feeling of doing everything right and still ending up looking at a low value. The first key to understanding this is that iron is not simply iron.
There are two forms in which iron appears in food. Heme iron is found in the blood and muscle pigment of animal foods, that is, in meat and fish. Non-heme iron occurs in plants, plus in part of the iron in animal tissue. Plants supply only non-heme iron.
The difference is not academic. Both forms use different routes through the gut wall. Heme iron has its own, fairly reliable door and is barely disturbed by accompanying substances in the meal. Non-heme iron has to be made available first and reacts sensitively to whatever else is on the plate.
Imagine two doors into the body. The heme door is wide and usually stands open. The non-heme door is narrower and can be held shut or opened wider from the outside more easily. As a vegan or vegetarian you almost only use the second door. That is not a disadvantage you simply have to accept, but a door you can actively open wider.
How big is the absorption difference really?
A rough orientation can help here. Heme iron is typically absorbed at around 25 to 30 percent. With non-heme iron, absorption fluctuates much more and often sits in the low single-digit percent range, depending on accompanying substances. These numbers are averages from research and not fixed values, but they show the direction.
The interesting message lies in the third number. The absorption of non-heme iron is not set in stone. It is movable. That is exactly what makes meal design so important and so effective for vegans and vegetarians.
With heme iron, absorption is largely fixed. With non-heme iron, it is shapeable. What is an advantage with animal food becomes your active lever with plant food.
What slows absorption and what promotes it
Non-heme iron reacts to two groups of substances. One group holds the door shut, the other opens it. Both appear regularly in a plant-based diet, often even in the same foods.
The brakes
Phytates are found in whole grains, legumes, nuts and seeds, that is, in exactly the foods that supply a lot of iron on a plant-based diet. They bind iron in the gut. Even small amounts can lower absorption considerably. That sounds like a contradiction, but it is solvable, because the phytate content can be reduced through preparation.
Tannins and other polyphenols are found above all in coffee, black and green tea as well as in some spices and red wine. A cup of coffee or tea directly with an iron-rich meal can noticeably brake absorption.
Calcium is a special case. It slows absorption not only of non-heme iron but also of heme iron, and at the same entry point into the gut cell. Large amounts of calcium, for example from fortified plant drinks or from supplements, therefore fit better not at the same time as the most iron-rich meal.
A detailed review of enhancers and inhibitors of iron absorption summarizes: phytates can lower non-heme iron absorption strongly in a dose-dependent way, even small amounts act. Polyphenols from tea and coffee inhibit as well, and calcium is the only one of the named substances that brakes both heme and non-heme iron.
For you this means: the inhibitors are real, but each of them can be worked around through timing or preparation.
Milman NT. J Nutr Metab. 2020;2020:7373498. DOI: 10.1155/2020/7373498The most important enhancer
Against this stands a strong helper: vitamin C, that is, ascorbic acid. It keeps iron in a form the gut takes up more easily, and it can partly cancel out the inhibiting effect of phytates and polyphenols. In studies, vitamin C clearly increased the absorption of non-heme iron from a meal.
A controlled investigation showed that ascorbic acid can prevent the dose-dependent inhibition of non-heme iron absorption by polyphenols and phytates. The enhancing effect was so clear that the researchers describe vitamin C as a practical lever to improve absorption from plant-based meals.
Concretely this means: a vitamin C source with an iron-rich meal can make up part of what phytates and tannins brake.
Siegenberg D et al. / current reproduction in Am J Clin Nutr. DOI: 10.1016/j.ajcnut.2023.06.005The common worry goes: plant iron is poorly available, so plant-based eating is a problem when it comes to iron. Looked at more closely, plant iron is above all shapeable. You lose absorption in one place and can deliberately bring it back in another. How to put this into everyday practice is laid out in detail in the article Improving iron absorption.
What does the research say about iron status?
Now for the honest stocktaking. When you compare large groups, a clear pattern emerges: vegetarians and vegans have lower iron stores on average than omnivores. That does not mean every individual has a deficiency. It means the risk is shifted.
A systematic review with meta-analysis pooled data from 24 cross-sectional studies. Adult vegetarians had clearly lower ferritin values on average than non-vegetarian comparison groups, on average around 30 micrograms per litre lower.
Interesting: the effect was strongest in men and smaller in pre-menopausal women. For you this means that lower stores on a plant-based diet are the rule, but not a fate.
Haider LM et al. Crit Rev Food Sci Nutr. 2018;58(8):1359-1374. DOI: 10.1080/10408398.2016.1259210A literature review of the iron status of vegetarians describes that vegetarians almost consistently have lower ferritin values than non-vegetarians. Women of childbearing age in particular showed a high proportion of depleted iron stores in some investigations.
At the same time the authors stress that a well-planned plant-based diet can supply enough iron. So this is about planning, not about giving up plant food.
Pawlak R et al. Am J Lifestyle Med. 2018;12(6):486-498. DOI: 10.1177/1559827616682933A second, often overlooked finding is encouraging: the body appears to adapt. Those who eat plant-based for longer or have lower stores tend to absorb more from non-heme iron. This adaptation is limited and does not replace checking your values when symptoms exist, but it shows that the body does not react rigidly.
A controlled study on the adaptation of non-heme iron absorption on a vegan diet found indications that absorption from plant food can be up-regulated over time. So the body responds to the lower store and gets more out of the iron that is present.
This explains why many long-term vegans hold stable values, even though the calculated absorption per meal appears lower.
Mol Nutr Food Res. 2025. DOI: 10.1002/mnfr.70096Good plant iron sources
Plant food is by no means poor in iron. On the contrary, many people eating plant-based even take in more total iron than omnivores. So this is less about quantity and more about the right choice and combination.
Iron-rich plant foods
- Legumes: lentils, chickpeas, white and black beans, soybeans. A load-bearing pillar of plant iron supply.
- Soy products: tofu and tempeh supply relevant iron, tempeh often with a more favourable phytate profile thanks to fermentation.
- Seeds and kernels: pumpkin seeds, sesame and tahini, sunflower seeds, flaxseed.
- Whole grains and pseudo-grains: oats, amaranth, quinoa, millet.
- Dark green vegetables: spinach, chard, kale, rocket. The content is solid, and absorption benefits strongly from vitamin C.
- Dried fruit and more: apricots, dark chocolate with a high cocoa content, parsley.
Higher risk does not necessarily mean deficiency
Here is the most important framing of the whole text. A higher statistical risk is not a verdict about you personally. It is a reason to look more closely, not a reason to question your plant-based diet.
Classic medicine looks first at the question of whether a treatment-requiring anaemia is present. That is sensible and important. What can be added from an integrative view is the earlier look: are your stores enough for freedom from symptoms, even when there is no anaemia yet? This functional range becomes especially relevant on a plant-based diet, because the stores are lower on average.
This also makes clear why the bare lower lab limit for ferritin is often not enough. It tells you when a deficiency is statistically likely, not when you feel well again. With symptoms, many experts orient toward a target above 100 micrograms per litre. What ferritin actually measures and why this target value can make sense is explored in the article Ferritin value: what is normal?.
The question is not whether you, as a vegan or vegetarian, should fall back on meat. The question is whether your iron values are well accompanied. A plant-based diet with a plan, a vitamin C combination and occasional value checks can absorb the higher risk factor well.
When diet alone is not enough
Sometimes the choice is right, the combination fits, and still the values stay low or the symptoms remain. That is not a failure of the plant-based diet. There can be other causes, such as heavy menstrual bleeding, an increased demand in sport or a disturbed absorption in the gut.
In such cases it makes sense to look for the cause rather than just eat more. When the stores are clearly empty, iron preparations or, with a clear indication, an iron infusion can play a role. Common tablets and modern infusion preparations are usually not of animal origin, but this should be checked case by case. Whether, when and how to treat belongs in a medical assessment, with an eye on indication and contraindications such as a possible iron overload.
More on the causes that can lie behind a stubborn deficiency can be found in the article Causes of iron deficiency. And the full picture, from diagnosis to infusion, is laid out in the pillar article on iron deficiency and iron infusions.
Eating plant-based asks for a little more attention when it comes to iron. That attention is well invested, because it turns a higher risk into a well-steerable factor.
And now you know why, with plant iron, it is not about the amount on the plate, but about how much of it reaches your body, and how much of that you can shape yourself.
Frequently asked questions
Do vegans and vegetarians inevitably develop iron deficiency?
No. A fully plant-based or meat-free diet does not automatically lead to a deficiency. Studies do show lower iron stores on average than in omnivores. So the risk is higher, but deficiency is not automatic. A well-planned plant-based diet can provide enough iron.
What is the difference between heme iron and non-heme iron?
Heme iron is found in the blood pigment of animal foods and is absorbed quite well through its own pathway. Non-heme iron occurs in plants and in part of the iron in animal tissue, and it is absorbed through a pathway that depends strongly on inhibitors and enhancers in the meal. Plants contain only non-heme iron.
Why is plant iron absorbed less well?
Non-heme iron first has to be made available in the gut and reacts sensitively to accompanying substances. Plant foods often contain phytates from whole grains and legumes as well as tannins from coffee and tea, which bind iron. As a result, proportionally less iron from a meal ends up in the body than with heme iron.
Which plant foods contain a lot of iron?
Good plant iron sources include legumes such as lentils, chickpeas and white beans, plus tofu and tempeh, pumpkin seeds, sesame, oats, amaranth, quinoa and dark green leafy vegetables. What matters is not only the content, but how well the iron from them is absorbed.
How can I improve iron absorption as a vegan?
One simple direction is to combine iron-rich meals with a vitamin C source, such as bell pepper, citrus juice or berries. Coffee and black tea fit better between meals. Soaking, sprouting and sourdough fermentation can lower the phytate content. More detail in the article on iron absorption.
Does calcium inhibit iron absorption?
Calcium can temporarily slow iron absorption from a meal, and it affects both heme and non-heme iron. In practice it can make sense not to take large amounts of calcium, for example from supplements or fortified plant drinks, at the same time as the most iron-rich meal. Spread across the day, the effect is relativized.
Does the body adapt to a plant-based diet?
There are indications that the body can up-regulate absorption of non-heme iron when stores are lower and on a longer-term plant-based diet. This adaptation is real but limited. It does not replace checking your values if symptoms persist.
Which ferritin value is sensible for vegans and vegetarians?
The sensible target value does not fundamentally differ from that of other people. What matters is that the bare lower lab limit is not an optimal value. With symptoms, many experts orient toward a target above 100 micrograms per litre. The individual target value belongs in a medical assessment.
Are iron tablets or infusions suitable for vegans?
Common iron preparations and modern infusion preparations are usually not of animal origin, but this should be checked case by case. Whether and which form makes sense depends on values, symptoms and tolerability and belongs in a medical assessment, not in self-medication.
How do I notice that my iron is running low?
Possible signs are persistent tiredness, exhaustion, trouble concentrating, hair loss, pale skin, restless legs or reduced exercise capacity. These signs are nonspecific. Clarity only comes from a blood test with ferritin and accompanying values.
Read on in the Iron Guide
Sources
- Haider LM, Schwingshackl L, Hoffmann G, Ekmekcioglu C. The effect of vegetarian diets on iron status in adults: A systematic review and meta-analysis. Crit Rev Food Sci Nutr. 2018;58(8):1359-1374. DOI: 10.1080/10408398.2016.1259210 [Meta-analysis, 24 cross-sectional studies]
- Pawlak R, Berger J, Hines I. Iron Status of Vegetarian Adults: A Review of Literature. Am J Lifestyle Med. 2018;12(6):486-498. DOI: 10.1177/1559827616682933 [Review, literature review]
- Milman NT. A Review of Nutrients and Compounds, Which Promote or Inhibit Intestinal Iron Absorption. J Nutr Metab. 2020;2020:7373498. DOI: 10.1155/2020/7373498 [Review of inhibitors and enhancers]
- Ascorbic acid prevents the dose-dependent inhibitory effects of polyphenols and phytates on nonheme-iron absorption. Am J Clin Nutr. 2023. DOI: 10.1016/j.ajcnut.2023.06.005 [RCT, absorption study in humans]
- Plant-Based Diet and Risk of Iron-deficiency Anemia. A Review of the Current Evidence and Implications for Preventive Strategies. Curr Nutr Rep. 2025. DOI: 10.1007/s13668-025-00671-y [Review]
- Dietary Adaptation of Non-Heme Iron Absorption in Vegans: A Controlled Trial. Mol Nutr Food Res. 2025. DOI: 10.1002/mnfr.70096 [RCT, controlled dietary study]
- Hurrell R, Egli I. Iron bioavailability and dietary reference values. Am J Clin Nutr. 2010;91(5):1461S-1467S. DOI: 10.3945/ajcn.2010.28674F [Review of bioavailability]
- Gibson RS, Perlas L, Hotz C. Improving the bioavailability of nutrients in plant foods at the household level. Proc Nutr Soc. 2006;65(2):160-168. DOI: 10.1079/PNS2006489 [Review of preparation and phytate reduction]
- Enhancing iron and zinc bioavailability in maize through phytate reduction: fermentation, soaking and germination. Front Nutr. 2024;11:1478155. DOI: 10.3389/fnut.2024.1478155 [In vitro, experimental study on phytate reduction]
- Saunders AV, Craig WJ, Baines SK, Posen JS. Iron and vegetarian diets. Med J Aust. 2013;199(S4):S11-S16. DOI: 10.5694/mja11.11494 [Review of iron and vegetarian diets]
This article serves general information and does not replace medical advice, diagnosis or treatment. Whether and how an iron deficiency should be assessed or treated belongs in an individual medical assessment. Part of the relationships mentioned rests on reviews and clinical experience, whose strength of evidence differs from randomized trials.