Iron and women: why so many of us are deficient and what

to do about it

Fatigue that sleep does not fix. Feeling cold when everyone else is fine. Brain fog that makes concentrating feel like pushing through mud. These are symptoms many women are told are just part of life. Often, they are signs of iron deficiency. Iron deficiency is the most common nutritional deficiency in the world, and women are disproportionately affected. This article covers what iron actually does, why women need more of it, and the most effective ways to get it from food.

What does iron actually do?

Iron is a trace mineral, meaning your body needs it in small amounts, but its role is anything but minor. Over 60% of the iron in your body is found in haemoglobin, the protein in your red blood cells that carries oxygen from your lungs to every cell in your body.

A further 8% is in myoglobin, which stores oxygen in your muscles. The rest is involved in energy production, immune function, and a broad range of enzyme activity that keeps your metabolism running properly.

When your iron stores are low, your body cannot make enough functional red blood cells. Less oxygen reaches your tissues. Everything slows down. That is why the fatigue of iron deficiency feels so total rather than just being tired.

Why women are more at risk

The average adult woman has around 2g of iron in her body compared to 4g in the average adult man. The difference comes down to menstruation. Women lose additional iron every month through blood loss, around 0.5mg extra per day on average, on top of the baseline losses everyone experiences through the gut, sweat, and skin.

During pregnancy, requirements increase further still, with the body needing an extra 2mg per day to support foetal development and the expansion of blood volume. Breastfeeding adds another layer of demand.

UK national diet data consistently shows that girls aged 11 to 18 and women aged 19 to 49 are among the groups most likely to have iron intakes below the recommended level. Around 10% of women require more than the standard RNI of 14.8mg per day due to particularly heavy menstrual losses.

The two types of iron in food

Not all dietary iron is equal, and this is one of the most important things to understand if you are trying to improve your levels.

Haem iron is found only in animal flesh: red meat, poultry, and fish. It is already in a form your body can use directly, and absorption rates are 20 to 30%. It is also less affected by other things you eat at the same meal, making it the most reliable dietary source.

Non haem iron is found in plant foods including lentils, beans, tofu, spinach, fortified cereals, nuts, and seeds, as well as in eggs and dairy. Absorption rates are significantly lower at 1 to 10%, and unlike haem iron, it is heavily influenced by what else you eat at the same time.

For women eating plant-based diets, this distinction matters a great deal.

What helps iron absorption and what blocks it

Vitamin C is the most powerful enhancer of non-haem iron absorption. Eating a source of vitamin C alongside a plant-based iron source, such as squeezing lemon over lentils or adding red pepper to a spinach dish, can significantly increase how much iron your body actually takes up.

Haem iron also helps. Eating a small amount of meat or fish alongside plant iron sources improves absorption of the non-haem iron too, which is worth knowing if you eat a mostly plant-based diet with occasional animal foods.

On the other side, certain compounds compete with iron for absorption. Phytates, found in wholegrains and legumes, and oxalates, found in spinach and rhubarb, bind to iron and reduce how much is absorbed. Tannins in tea and coffee have a similar effect. Drinking tea or coffee with or immediately after an iron rich meal is one of the most common ways women unknowingly reduce their iron absorption.

Calcium also competes with iron at the absorption site in your gut. High calcium meals or supplements taken at the same time as iron rich foods can lower how much iron you absorb.

Signs you might be low in iron

Iron deficiency develops in stages. In the early stages, your stores are depleted, but your red blood cells are still functioning normally, so you may feel off without understanding why. By the time anaemia develops, haemoglobin levels have dropped and symptoms are usually obvious.

Signs to look out for include persistent fatigue and weakness; feeling cold all the time, particularly in your hands and feet; difficulty concentrating; headaches; shortness of breath during activity that would not normally wind you; pale skin; and brittle or spoon-shaped nails.

If several of these sound familiar, the most useful first step is a blood test rather than self-supplementing. Testing for serum ferritin, which measures your iron stores, gives a more complete picture than haemoglobin alone and can catch deficiency before it becomes anaemia.

The best food sources of iron for women

For haem iron: beef, lamb, liver, chicken, turkey, sardines, and salmon are all strong sources. Liver in particular is one of the most concentrated sources of iron available, though it should be avoided during pregnancy due to its very high vitamin A content.

For non-haem iron: red lentils, chickpeas, kidney beans, tofu, pumpkin seeds, cashews, quinoa, fortified breakfast cereals, and dark leafy greens. UK wheat flour is also compulsorily fortified with iron, meaning bread contributes meaningfully to many women's intake.

A practical combination that works well: lentil soup with a squeeze of lemon and a side of crusty bread. Iron from multiple sources, vitamin C to enhance absorption, and no tea for at least an hour afterwards.

The boops takeaway

If you are a woman in your 20s, 30s or 40s and you are tired in a way that sleep does not touch, iron is worth investigating before you assume it is just your life. Get your ferritin tested, not just your haemoglobin. In the meantime, eat iron rich foods alongside vitamin C, hold off on the tea for an hour after meals, and make sure you are not inadvertently blocking the iron you are already eating. Small changes to timing and combinations can make a meaningful difference to how much your body actually absorbs.

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