Articles · Nutrients
Tired all the time? What iron has to do with it
Why iron matters for energy, who runs low, how to absorb more of it from food (hint, a squeeze of lemon), and why a blood test beats guessing.
· 4 min read
Everybody gets tired. But if you're worn out most days, short of breath on the stairs, and pale, there's a chance your body is short of iron. It's the most common nutrient deficiency in the world. How does it happen, and what can you do about it with food?
What does iron do?
Most of the iron in your body sits in haemoglobin, the protein in red blood cells that carries oxygen from your lungs to every other part of you. Without enough iron, the body makes fewer, smaller red blood cells, and the tissues get less oxygen. That's iron-deficiency anaemia, and tiredness is its best-known sign.
Iron also helps muscles store oxygen and plays a part in growth, the brain and the immune system.
Think about it: Have you ever had your iron checked? Many people with low iron go years without knowing.
Who runs low?
- Women who have periods, especially heavy ones, lose iron every month.
- Pregnant women need much more iron for the baby and the extra blood.
- Babies, toddlers and teenagers, who are growing fast.
- Frequent blood donors.
- People who eat little or no meat, who can get enough, but need to plan for it.
- People with conditions that affect absorption or cause blood loss, such as coeliac disease or a bleeding ulcer.
In the United States, the recommended intake for adults is 8 mg a day for men and for women over 50, and 18 mg a day for women aged 19 to 50.
Two kinds of iron
- Haem iron, from meat, poultry and fish, is absorbed well.
- Non-haem iron, from plants, eggs and fortified foods, is absorbed less well, and how much you take up depends a lot on what else is on your plate.
Good plant sources include lentils, beans, chickpeas, tofu, dark leafy greens, pumpkin seeds, dried apricots and iron-fortified breakfast cereals.
Apollo in the Forge of Vulcan, Diego Velázquez, 1630, Museo del Prado, Madrid. The god Apollo walks into Vulcan's forge with startling news, and the blacksmiths stop mid-hammer, a glowing bar of iron on the anvil. In your body, iron does quieter work: it carries oxygen in every red blood cell. Public domain · Wikimedia CommonsHow to absorb more iron from your food
- Add vitamin C to the meal. A squeeze of lemon on lentils, peppers in a bean chilli, a glass of orange juice with fortified cereal, or a few strawberries all help the body absorb non-haem iron.
- Keep tea and coffee away from iron-rich meals. Their polyphenols bind iron: in one study, black tea drunk with a meal cut the iron absorbed from it by 79–94%. Leave an hour or so between the meal and the cuppa.
- Mix sources. A little meat or fish in a meal also helps you absorb the iron from the vegetables alongside it.
- Mind the calcium. Calcium can reduce iron absorption too, so if you take a calcium supplement, take it at a different meal.
Try this: Swap the after-dinner tea for a mid-afternoon one, and add lemon juice or chopped peppers to your next lentil or bean dish.
Should you just take an iron supplement?
Not without a test. Tiredness has many causes, from poor sleep to thyroid problems, and too much iron is harmful: it builds up in the body and can damage the liver and other organs. A simple blood test (haemoglobin and ferritin) tells you whether iron is the problem. If it is, your doctor can advise the right dose, and look for the cause.
Think about it: If you've felt tired for weeks, could it be worth asking your doctor for a blood test instead of another coffee?
Quick quiz
Which kind of iron does the body absorb better: from meat or from beans?
From meat (haem iron). Iron from beans and other plants is absorbed less well, but vitamin C in the same meal helps.
What simple addition helps you absorb more iron from a lentil soup?
Something rich in vitamin C, such as a squeeze of lemon juice, chopped peppers or tomatoes.
Why not take iron tablets "just in case"?
Too much iron builds up and can harm the liver and other organs, and tiredness has many other causes. Get a blood test first.
Sources
General information, not medical advice. If you have a health condition, are pregnant or take medication, ask a doctor or dietitian what is right for you.