At a glance:
- Iron deficiency is the most common micronutrient deficiency among women of reproductive age, affecting approximately 30% of this age group.
- Typical symptoms include chronic fatigue, pale skin, shortness of breath and difficulty concentrating.
- The absorption rate for heme iron from meat is 15–35%, compared with just 2–20% for iron from plant sources — combine plant-based iron with foods rich in vitamin C.
- Iron supplements should only be taken on a doctor’s recommendation, based on ferritin and hemoglobin blood test results.
What causes iron deficiency in women, and who is at risk?
According to the World Health Organization (WHO), iron deficiency in women is the most common mineral deficiency worldwide: approximately 30% of women of reproductive age have iron deficiency anemia. The main cause is regular blood loss through menstruation, compounded by insufficient iron in the diet and impaired absorption. In women who train regularly, the risk is further increased by hemolysis caused by intense physical exertion — the mechanical destruction of red blood cells (Beard & Tobin, 2000).
According to Estonian dietary recommendations, women aged 19–50 need 18 mg of iron a day, and pregnant women need up to 27 mg, while 8 mg is sufficient for men (Health Board, 2015). This more than twofold difference explains why iron deficiency particularly affects women.
What are the symptoms of iron deficiency in women?
The early signs of iron deficiency often resemble general fatigue or overtraining, making them easy to overlook. The clinical picture develops gradually:
- Chronic fatigue and weakness — oxygen-carrying capacity falls as hemoglobin levels drop
- Pallor of the skin, nail beds and inner lining of the lower eyelid
- Shortness of breath even after mild exertion
- Heart palpitations (tachycardia) and a rapid pulse
- Cold hands and feet, dizziness when standing up
- Difficulty concentrating and irritability
- Brittle nails and increased hair loss
- Pica — cravings for non-food substances (ice, clay)
Many of these signs also overlap with the general decline associated with aging; Symptoms of aging II provides a useful overview of which signs warrant separate assessment and when to see a doctor.
A blood test confirms the diagnosis. Ferritin below 30 µg/l indicates depleted iron stores even before hemoglobin levels fall (Camaschella, 2015). Serum iron and transferrin saturation are also assessed.
Which foods should you eat to prevent iron deficiency?
Adjusting your diet is the first and most effective step in preventing iron deficiency and addressing a mild deficiency. It is important to distinguish between two forms of iron: heme iron (from meat, fish and poultry) has an absorption rate of 15–35%, while non-heme iron (from plants) has an absorption rate of just 2–20% (Camaschella, 2015).
Sources of heme iron (bioavailability 15–35%)
| Food | Iron per 100 g |
|---|---|
| Beef liver | ~6 mg |
| Beef (lean) | ~2–3 mg |
| Sardines (canned) | ~3 mg |
| Chicken breast | ~1 mg |
Sources of non-heme iron (bioavailability 2–20%)
| Food | Iron per 100 g |
|---|---|
| Pumpkin seeds | ~8 mg |
| Lentils (cooked) | ~3 mg |
| Spinach (cooked) | ~3.6 mg |
| Tofu | ~3 mg |
| Oat flakes | ~2 mg |
The absorption of plant-based iron depends heavily on the composition of your food and the conditions in your digestive tract. Read more about how pH and healthy eating affect the behavior and bioavailability of minerals in the digestive tract.
How can you improve iron absorption from food?
Your food choices can significantly affect absorption — in either direction.
Factors that enhance absorption:
– Vitamin C — taking 100 mg of vitamin C with a meal increases non-heme iron absorption by up to 4–6 times (Cook & Reddy, 2001). Add bell pepper, lemon juice or kiwi to your spinach salad.
– Meat and fish protein (meat factor) — stimulates iron transport mechanisms in the intestine.
– Fermented foods — reduce the phytate content of legumes and grains.
Factors that inhibit absorption:
– Tea and coffee — the tannins they contain bind iron; drink them at least 1 hour after a meal.
– Calcium in high doses (milk, cheese) consumed with an iron-rich meal.
– Phytates in whole grains and legumes — reduce their effects by soaking and sprouting these foods before use.
– Polyphenols in red wine.
Post-workout nutrition – II takes a closer look at how food choices during recovery affect mineral replenishment and recovery after a hard workout.
Iron and training: What do active women need to know?
Physically active women need more iron than women who do not train. Iron deficiency is 2–3 times more common in endurance athletes than in the general population (Beard & Tobin, 2000). There are several reasons:
- Sweating — iron is lost through sweat, particularly during prolonged, intense exercise.
- Changes in gastrointestinal microcirculation — intense training increases intestinal permeability and the risk of bleeding.
- Mechanical hemolysis — in runners, some red blood cells rupture on impact (known as foot-strike hemolysis).
- Stimulation of erythropoiesis — regular training increases red blood cell production, which uses more iron.
Hormonal balance is also linked to overall vitality and recovery; nutrition and testosterone explains how nutrition affects hormone levels and energy metabolism.
Women who train regularly are advised to have their ferritin levels checked at least once a year, especially if they have a high training load and follow a predominantly plant-based diet (Milman, 2011).
When are iron supplements needed?
For mild iron deficiency, optimizing your diet is often enough. For moderate to severe anemia, oral iron supplements (ferrous sulfate, ferrous fumarate, ferrous gluconate) are effective, but should be taken on a doctor’s recommendation. An iron overdose is toxic, and high doses of iron interfere with zinc and copper absorption (Camaschella, 2015). The Health Board recommends having a blood test to measure your ferritin level before taking supplements — this is the only way to tailor the dose accurately.
References
- Camaschella C. (2015). Iron-deficiency anemia. New England Journal of Medicine. 372(19):1832–1843. PMID: 25946283
- Beard JL, Tobin B. (2000). Iron status and exercise. American Journal of Clinical Nutrition. 72(2 Suppl):594S–597S. PMID: 10919969
- Cook JD, Reddy MB. (2001). Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet. American Journal of Clinical Nutrition. 73(1):93–98. PMID: 11157333
- Milman N. (2011). Anemia — still a major health problem in many parts of the world! Annals of Hematology. 90(4):369–377. PMID: 21181476
- Health Board. (2015). Estonian dietary and physical activity recommendations. National Institute for Health Development, Tallinn.
Frequently asked questions
What are the first signs of iron deficiency in women?
Early signs include chronic fatigue, pale skin, dizziness and difficulty concentrating. These symptoms are often vague and resemble those of general stress or overtraining, so it is important to have a blood test to check your ferritin level.
How much iron should a woman get each day?
According to Estonian dietary recommendations, the recommended daily intake for a woman aged 19–50 is 18 mg of iron. Up to 27 mg is recommended during pregnancy. If you follow a plant-based diet, you are advised to consume approximately 1.8 times as much, because non-heme iron is less readily absorbed.
Can iron deficiency be treated through diet alone?
For mild iron deficiency, optimizing your diet may be enough — particularly by combining sources of heme iron (meat, fish) with foods rich in vitamin C. For moderate to severe anemia, iron supplements are usually needed at a dose prescribed by a doctor.
Why are physically active women at greater risk of iron deficiency?
Training increases your iron requirements: iron is lost through sweat, intense training loads cause changes in gastrointestinal microcirculation, and runners experience mechanical hemolysis. Physically active women are therefore advised to monitor their ferritin levels regularly.
Can you start taking iron supplements on your own?
No. An iron overdose is toxic, and high doses interfere with the absorption of other minerals (zinc, copper). Before taking supplements, it is important to have a blood test to measure your ferritin and hemoglobin levels and consult your family doctor.
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