Iron: Energy, Oxygen and Blood Health Explained
Iron: Energy, Oxygen and Blood Health Explained
Dragging yourself through a packed workday, ending it with a takeaway supper from a late-night chippy after 10pm, and still feeling flat the next morning? Poor sleep is the usual suspect, but low iron is another one worth knowing about.
What Is Iron?
Iron is an essential mineral that your body needs to make haemoglobin, and the body cannot make it, so it must come from food. Haemoglobin is the protein in red blood cells that carries oxygen from your lungs to every part of your body.
Iron is also part of myoglobin, a protein that supplies oxygen to muscles. It supports growth, brain development and the making of some hormones.
Food iron comes in two types. Haem iron, found in meat, poultry and seafood, is absorbed more easily. Non-haem iron, found in plants and fortified foods, is harder for your body to take up. Meat and seafood actually contain both types.
Why Do People Take It?
Keeping oxygen moving so you feel less tired
When iron runs short, your bone marrow cannot make enough haemoglobin. Less oxygen reaches your tissues, and since cells need oxygen to make energy, fatigue follows. Think of it as a delivery fleet with too few vehicles.
Common warning signs include constant exhaustion, pale skin, a racing heartbeat, breathlessness on the stairs, dizziness and brittle nails. A Singapore General Hospital pharmacist notes that iron deficiency is the most common cause of anaemia in Singapore. Anaemia simply means too few healthy red blood cells.
One caution: if you are not iron deficient, there is no evidence that taking iron supplements for energy will help.
Supporting muscles, stamina and immunity
Myoglobin acts like a small oxygen tank inside your muscles, so the oxygen is on hand when you move. Iron is also one of several vitamins and minerals your immune system needs at every stage of its response.
Long-distance runners are among the groups more likely to end up with low iron. Running can cause tiny amounts of bleeding in the gut and break down red blood cells faster. Worth remembering if your weekends are spent on long runs along canal towpaths.
Backing brain development and focus
In children, iron is needed for growth and brain development. A shortage can delay development, and the effects may be permanent. Toddlers and teenagers are at risk because they grow quickly and often eat unevenly.
Milk is a very poor source of iron, so toddlers who drink lots of milk and skip other foods can develop what is called milk anaemia. In adults, iron-deficiency anaemia can show up as low energy and problems with concentration and memory.
Meeting higher needs during periods and pregnancy
Women need more iron than men because of blood lost through menstruation. Pregnancy raises the need further because of the growing baby and extra blood circulation. In younger women, iron deficiency anaemia is mainly due to heavy menstrual loss that is not replaced, and it can go untreated or undetected.
Iron deficiency is the most common cause of anaemia in pregnancy. HealthHub notes that in 2011, up to two in five women of reproductive age in Southeast Asia had iron deficiency anaemia.
Routine check-ups, such as those offered through your GP surgery, are a good habit. But if you have felt tired for weeks, ask your GP whether a blood test for iron makes sense. Long work hours make it easy to shrug off the signs.
Bioavailability & Absorption
Not all the iron on your plate ends up in your body. Haem iron is absorbed better than non-haem iron, and other foods affect it less. That is why people who eat no meat, poultry or seafood need almost twice as much iron.
Some partners help. HealthHub suggests pairing plant iron with vitamin C fruits such as guava, papaya, oranges and kiwi. Mixing a little meat, fish or poultry with beans or dark leafy greens can improve absorption of the plant iron up to three times. Spring greens stir-fried with a few prawns, followed by an orange, is a good example.
Other things get in the way. Coffee and tea contain caffeine and tannins that inhibit iron absorption, so HealthHub advises having them a couple of hours away from meals. Bran fibre, large amounts of calcium and plant substances called phytates and tannins can also reduce absorption. SingHealth also advises keeping iron apart from milk and calcium-rich foods. A milky tea straight after lunch is tea and milk together, so it is worth spacing out.
Your body excretes very little iron, so it controls absorption tightly. A hormone called hepcidin blocks iron absorption when your stores are already sufficient. More is not always better. Cooking in cast-iron cookware can also add a little iron to your food.
Safety Basics
Most healthy people can meet their needs through food. Supplements are different, because iron is a nutrient where too much causes real problems. Excess iron can damage the liver, heart and other organs.
High-dose iron supplements, especially on an empty stomach, can cause an upset stomach, constipation, nausea, abdominal pain, vomiting and diarrhoea. Large amounts may also inflame the stomach lining and cause ulcers. Too much iron can also lower zinc absorption.
Some people need extra care:
- People with hereditary haemochromatosis, a condition where iron builds up to toxic levels, risk liver, heart and other serious problems.
- HealthHub asks you to tell your healthcare professional if you have thalassaemia (a blood disorder) or haemochromatosis, or take other medicines, supplements or traditional or herbal products.
- The Linus Pauling Institute advises that men and postmenopausal women generally avoid multivitamins containing iron.
- Iron can weaken the effect of levodopa and levothyroxine.
- Accidental overdose of iron products is a leading cause of fatal poisoning in young children, so store them well out of reach.
Regular use of anti-inflammatory painkillers such as aspirin and ibuprofen can cause stomach bleeding, which in turn drains iron. Supplement awareness is growing among younger working adults, while older generations tend to be more sceptical. Both instincts have a point: take tiredness seriously, but do not self-prescribe. Taking too many iron supplements without supervision can be dangerous, so speak to your doctor or pharmacist before starting.
Natural Food Sources
- Red meat, poultry and liver: HealthHub lists liver as the richest haem source, but pregnant women and people with high cholesterol should limit it and cook it well.
- Shellfish and fish: Clams, oysters, sardines and prawns are good haem sources. The cockles in a takeaway fried noodle dish count, but the dish is heavy on sodium and fat, so it should not be your iron plan.
- Egg yolks: Eggs, especially yolks, are on MedlinePlus's list of good sources.
- Dark leafy greens: Kailan and broccoli are non-haem sources.
- Beans and soy foods: Tofu, tempeh, soy beans, lentils and chickpeas suit vegetarians well.
- Wholegrains and fortified foods: Wholegrain noodles, brown rice and iron-fortified cereals and breads help.
- Dried fruit and nuts: Prunes, raisins, wolfberries (gou qi zi), nuts and seeds make easy snacks.
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Final Thoughts
Iron is a quiet nutrient. You rarely notice it until you run low, and then everything from your morning commute to your concentration feels harder. Food is the best starting point, and a few smart pairings, like greens with vitamin C fruit, make a real difference.
If you suspect low iron, get it checked rather than guessing. A simple blood test tells you far more than a pill bottle can.
This article is for general informational purposes and is not a substitute for professional medical advice. Please consult a qualified healthcare professional before making any changes to your diet or supplement routine.
References
- NIH Office of Dietary Supplements
https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/ - Harvard T.H. Chan School of Public Health
https://nutritionsource.hsph.harvard.edu/iron/ - MedlinePlus (NIH)
https://medlineplus.gov/ency/article/002422.htm - MedlinePlus (NIH)
https://medlineplus.gov/ency/article/000584.htm - Linus Pauling Institute (Oregon State University)
https://lpi.oregonstate.edu/mic/minerals/iron - HealthHub Singapore 🇸🇬 SG
https://www.healthhub.sg/well-being-and-lifestyle/food-diet-and-nutrition/low-in-energy-you-could-be-low-in-iron