Iron is an essential trace element that our body needs for numerous functions – including oxygen transport, the formation of red blood cells, and supporting the immune system. An iron deficiency can manifest itself through symptoms such as fatigue, paleness, or difficulty concentrating. Proper nutrition plays a key role in preventing this.
But how can you improve your iron absorption and prevent iron deficiency? Here you'll learn which foods help, which factors influence absorption, and when supplementation with dietary supplements might be beneficial.
The most important points in brief
Iron from animal-based foods (heme iron) is absorbed better than plant-based iron (non-heme iron).
Vitamin C and fruit acids improve iron utilization, whereas calcium, phytic acid and tannins inhibit absorption.
Women, athletes, and vegetarians often have a higher iron requirement and may benefit from targeted supplementation.
A blood test at the doctor's office can reveal whether the body has sufficient iron levels.
Iron in the diet:
The basics
Iron is found in various foods, but not all sources are equally bioavailable. There are two forms of iron:
1. Heme iron
Heme iron is found in animal-based foods such as meat, fish, and poultry. It is particularly well absorbed by the body, with an absorption rate of approximately 20 to 30%.
2. Non-heme iron
Non-heme iron is found in plant-based foods such as pulses, leafy green vegetables, whole grains, and nuts. The intake of non-heme iron is lower, at about 5 to 15%. However, it can be improved through targeted food combinations [1].
Iron-rich foods:
The best sources
Animal sources:
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Beef, pork and poultry
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Liver (very high iron content, but should be consumed in moderation)
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Fish and seafood, e.g. tuna and mussels
Plant sources:
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Lentils, chickpeas and white beans
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Spinach, chard and broccoli
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Oat flakes, millet and quinoa
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Nuts and seeds, especially sunflower seeds and almonds [2]
Optimize iron absorption:
Tips for a supportive diet
The bioavailability of iron from food can be increased or decreased by certain dietary habits.
Here are some tips for you:
Foods that promote growth:
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Vitamin C increases iron absorption from plant sources. Therefore, combine iron-rich foods with bell peppers, oranges, berries, or lemon juice for improved absorption.
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Fruits containing fruit acids can also promote iron absorption, e.g., pineapple or strawberries.
Inhibitory foods:
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Dairy products and calcium can inhibit iron absorption; therefore, they should not be consumed directly with iron-rich meals.
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Phytic acid is found in whole grains, legumes, and nuts, and it also reduces iron absorption. However, soaking or sprouting these foods can lessen this effect.
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Tannins and polyphenols are found in tea, coffee, and red wine. Avoid drinking these beverages directly with meals to prevent inhibiting iron absorption [3].
When is iron supplementation advisable?
Despite a balanced diet, many people fail to meet their iron requirements. Those particularly affected include:
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Women with heavy periods
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Pregnant women and breastfeeding mothers
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Vegetarians and vegans
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competitive athletes
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People with certain chronic diseases such as celiac disease or inflammatory bowel disease [2]
In these cases, dietary supplements can help meet your needs. If you frequently feel tired or lethargic, you may have an iron deficiency. A blood test will determine whether iron supplementation is advisable.
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Taking iron supplements correctly:
The most important rules
To ensure your body can optimally utilize the iron, you should pay attention to the following points:
1. Time of intake
Iron should ideally be taken on an empty stomach, about one hour before or two hours after a meal. This avoids interactions with other foods and minerals.
If you have a sensitive stomach, you can take the medication with a small meal.
2. Combination with Vitamin C
Vitamin C improves iron absorption. Combine your supplement with a glass of orange juice or a vitamin C capsule to increase absorption.
3. Avoid inhibitors
Avoid consuming dairy products, tea or coffee for at least one hour before and after taking [4].
4. Observe the dosage
Stick to the recommended amount – an overdose can cause side effects such as nausea, constipation or, in the worst case, iron overload [2].
Conclusion
Iron is essential for your health, but not all sources are equally bioavailable. Heme iron from animal-based foods is efficiently absorbed, while plant-based iron should be combined with vitamin C to improve absorption. At the same time, calcium, phytic acid, and tannins inhibit iron absorption.
If you experience symptoms like fatigue despite an iron-rich diet, a blood test can help determine your iron status. With the right diet and targeted adjustments, you can keep your iron levels stable in the long term and feel more energetic.
Our expert
Dr. Anne Bansleben
Nutritionist
Key areas:
Product development in analytical chemistry | botany | microbiology
How can I meet my iron needs through diet?
Through a combination of animal (heme iron) and plant (non-heme iron) iron sources . Foods rich in vitamin C help improve absorption.
Which foods are particularly high in iron?
- Animal sources : beef, liver, poultry, fish
- Plant-based sources : lentils, spinach, rolled oats, nuts, quinoa
Do I need iron supplements if I follow a vegetarian diet?
Not necessarily. However, vegetarians should pay attention to their diet and optimize their iron intake with vitamin C. A blood test can determine their needs.
What are the best plant-based sources of iron?
Lentils, chickpeas, spinach, quinoa, rolled oats, nuts and seeds (e.g. sunflower seeds).
How do I take iron supplements correctly?
Best taken on an empty stomach with vitamin C. Avoid dairy products, tea, or coffee before or after taking it .
References for further reading:
- Chang X, Lv C, Zhao G. A Dual Function of Ferritin (Animal and Plant): Its Holo Form for Iron Supplementation and Apo Form for Delivery Systems. Annual Review of Food Science and Technology 2023; 14:113–33.
- German Nutrition Society (DGE) Iron; 2025 [Status: 04.02.2025]. Available at: https://www.dge.de/gesunde-ernaehrung/faq/eisen/.
- Milman NT. A Review of Nutrients and Compounds, Which Promote or Inhibit Intestinal Iron Absorption: Making a Platform for Dietary Measures That Can Reduce Iron Uptake in Patients with Genetic Haemochromatosis. J Nutr Metab 2020; 2020(1):7373498. doi: 10.1155/2020/7373498.
- Siebenthal HK von, Moretti D, Zimmermann MB, Stoffel NU. Effect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women. Am J Hematol 2023; 98(9):1356–63. doi: 10.1002/ajh.26987.