Have you felt tired despite sleeping well? Do you get short of breath easily in everyday life, or struggle to maintain your energy throughout the day? Iron deficiency is one of the most common nutrient deficiencies in the world, and many people walk around with low iron levels without even knowing it. But why do iron stores become depleted so easily?
Iron is essential for the body. It is needed to transport oxygen, produce energy, and support a strong immune system. Despite this, it is surprisingly difficult to get enough iron through diet alone, and many factors can increase iron losses or reduce absorption. Below, we go through the most common reasons why iron deficiency develops and why it is so easy to fall short.
We consume too little iron through food
Many people assume that iron is easy to obtain from the diet, but the reality is more complex. The iron content of foods varies widely, and bioavailability, meaning how much iron the body can actually absorb, plays a crucial role.
Let us compare two meals and look at how much iron the body is able to absorb.
A spinach salad with chickpeas, quinoa, and nuts
Chickpeas, 100 g, → 2.9 mg of iron.
Quinoa, 100 g, → 2.8 mg of iron.
Spinach, 100 g, → 2.7 mg of iron.
Nuts, 30 g, → 1 mg of iron.
The total iron content of this meal is about 9.4 mg.
However, actual absorption is likely only around 0.5 to 1.8 mg, because the iron in these foods is non-heme iron. Non-heme iron is absorbed in limited amounts and is easily inhibited by other compounds in the diet, such as phytic acid and polyphenols.
A beef steak with potatoes and vegetables
Beef steak, 150 g, contains approximately 4.5 mg of iron.
Potatoes, 200 g, contain approximately 1.2 mg of iron.
Bell peppers, 50 g, contain approximately 0.6 mg of iron.
The total iron content of this meal is about 6.3 mg. In this case, approximately 2.5 to 3 mg of iron is absorbed, since iron from meat occurs as both heme iron and non-heme iron. Heme iron is absorbed much more efficiently, and the so-called meat factor can also enhance the absorption of non-heme iron.
What does this mean in practice?
Even though some plant-based foods contain as much or more iron than meat, the amount absorbed by the body can be significantly lower. This means that an iron-rich diet is not only about how much iron food contains, but also about how well the body can absorb it. It is entirely possible to meet iron needs through a well-planned diet, but it requires awareness and an understanding of how iron absorption works.
Menstruation and iron loss
An average menstrual period contains approximately 2 to 4 tablespoons of blood, corresponding to a loss of around 15 to 30 mg of iron. At the same time, it can be difficult to compensate for this loss through diet alone. Over time, iron stores may gradually become depleted.
For some women, menstrual bleeding is particularly heavy, leading to chronically low iron levels that can negatively affect both energy and overall well-being.
Pregnancy and breastfeeding, when iron needs increase dramatically
During pregnancy, iron requirements rise sharply, as iron is needed to increase blood volume, support fetal growth, and ensure healthy placental development. Daily needs increase from approximately 15 mg to around 27 mg, almost doubling.
Since many women enter pregnancy with already low iron stores, deficiency can develop early. After childbirth, iron losses continue through postpartum bleeding, and breast milk also contains iron, meaning that breastfeeding can further deplete iron stores.
Exercise and increased iron turnover
People who train frequently may use more iron than average, especially those who run or engage in high-intensity exercise. This is due to increased red blood cell production stimulated by training, which requires iron. Iron can also be lost through sweat during intense physical activity. In runners, repeated foot impact can destroy red blood cells in a process known as foot-strike hemolysis, further increasing iron requirements.
For these reasons, athletes, particularly women, are often at higher risk of iron deficiency.
Low stomach acid, a hidden cause of poor iron absorption
Stomach acid plays a crucial role in iron absorption, especially for non-heme iron from plant-based sources. When stomach acid levels are low, which is common during stress, aging, or the use of acid-suppressing medications, the body cannot convert iron from its ferric form to its ferrous form. As a result, iron passes through the digestive tract without being absorbed. One common example of acid-suppressing medication is omeprazole, frequently used for acid reflux.
Chronic disease and inflammation, when iron becomes trapped in the body
In chronic conditions such as inflammation, inflammatory bowel disease, or kidney disease, the body’s iron regulation changes. The immune system increases the production of hepcidin, a hormone that blocks the release of iron from the body’s stores. This means that even if iron intake is adequate, the body cannot use it efficiently.
The result can be iron deficiency anemia despite apparently normal iron stores in blood tests.
Medications and dietary factors that reduce iron absorption
Certain medications and foods can further inhibit iron absorption. Calcium-rich foods such as milk, cheese, and yogurt compete with iron for absorption in the intestine. Coffee and tea contain polyphenols that can reduce iron absorption by up to 60 percent. Phytic acid found in grains, legumes, and nuts binds iron and reduces its bioavailability. Acid-suppressing medications prevent the conversion of iron into its absorbable form.
Conclusion, iron deficiency develops gradually
Iron deficiency often develops slowly over time, and many people do not notice it until they begin to feel persistently tired, unfocused, and low in energy. Because we lose small amounts of iron every day and often consume too little through diet, deficiency can develop easily, particularly in women, athletes, and during pregnancy.
For this reason, it is important to be aware of iron levels and to review dietary habits. Have you ever considered how much iron you actually consume each day?
