Iron deficiency is one of the most common nutritional deficiencies in Ireland and worldwide. It affects people of all ages, but is particularly prevalent in women of childbearing age, pregnant women, teenagers, vegetarians and vegans, and people with certain digestive conditions. Understanding iron — how it works, how to recognise deficiency, and how to supplement effectively — is essential knowledge for a significant portion of the Irish population.
Why Iron Matters
Iron is an essential mineral with several critical functions:
- Oxygen transport: Iron is the central component of haemoglobin, the protein in red blood cells that carries oxygen from the lungs to every cell in the body. Low iron means lower haemoglobin levels — the basis of iron deficiency anaemia.
- Myoglobin: Iron is also a component of myoglobin, which stores and supplies oxygen to muscle cells.
- Energy metabolism: Iron is essential for mitochondrial energy production. Even without full anaemia, low iron stores (ferritin) can cause significant fatigue.
- Immune function: Iron plays a role in immune cell production and activity.
- Cognitive function: Adequate iron is important for neurotransmitter synthesis and brain function. Iron deficiency in children is associated with impaired cognitive development.
- Thyroid function: Iron is required for the production of thyroid hormones.
Signs and Symptoms of Iron Deficiency
Iron deficiency develops gradually through stages: iron depletion, iron-deficient erythropoiesis, and finally iron deficiency anaemia. Symptoms can begin before full anaemia develops:
- Fatigue and low energy — often the first and most prominent symptom
- Pallor (pale skin, inner eyelids, nail beds)
- Shortness of breath on exertion
- Heart palpitations
- Cold hands and feet
- Headaches and dizziness
- Difficulty concentrating ("brain fog")
- Brittle nails, sometimes with a "spoon" shape (koilonychia)
- Hair loss or thinning
- Restless legs syndrome
- Pica — unusual cravings for non-food items like ice, clay or chalk (a notable iron deficiency sign)
- Sore or swollen tongue
- Frequent infections
Many of these symptoms overlap with other conditions. If you suspect iron deficiency, always get a blood test before supplementing. Your GP can check serum ferritin (iron stores), haemoglobin, and full blood count.
Who Is at Higher Risk in Ireland?
- Women with heavy periods: The most common cause of iron deficiency in women. Heavy menstrual bleeding (menorrhagia) can result in significant iron losses each month.
- Pregnant women: Iron requirements nearly double in pregnancy to support fetal development and placenta formation. The HSE recommends iron supplementation during pregnancy when needed.
- Vegetarians and vegans: Plant-based diets provide non-haem iron (from plants) rather than haem iron (from meat), which is less bioavailable. Vegetarians and vegans typically need 1.8x more dietary iron than meat-eaters.
- Teenage girls: Growing bodies, menstruation beginning, and often poor dietary habits combine to create risk.
- Older adults: Reduced stomach acid (common in older adults) impairs iron absorption.
- People with digestive conditions: Coeliac disease, Crohn's disease and inflammatory bowel conditions can impair iron absorption.
- Regular blood donors: Each donation removes approximately 250mg of iron.
- Athletes: Particularly endurance athletes, who lose iron through foot-strike haemolysis, sweating and gastrointestinal losses.
Food Sources of Iron
Haem Iron (Higher Bioavailability)
Found in animal foods; approximately 25–30% is absorbed:
- Red meat (beef, lamb, pork) — one of the richest sources
- Liver and offal — extremely iron-rich (but not recommended during pregnancy due to high vitamin A)
- Poultry (darker meat)
- Oily fish and shellfish (oysters, clams, mussels are particularly high)
Non-Haem Iron (Lower Bioavailability)
Found in plant foods; typically 2–20% is absorbed depending on the meal context:
- Legumes: lentils, chickpeas, kidney beans, soybeans
- Tofu and tempeh
- Dark leafy greens: spinach, kale (though note calcium and oxalates reduce absorption)
- Fortified cereals and bread
- Pumpkin seeds
- Dried fruit (apricots, raisins, prunes)
- Quinoa
Maximising Iron Absorption
What you eat with iron-rich foods matters enormously:
Enhancers of Iron Absorption:
- Vitamin C: Consuming vitamin C alongside non-haem iron significantly increases absorption. A glass of orange juice, some peppers, or a squeeze of lemon can make a real difference.
- Haem iron: Having a small amount of meat alongside plant iron sources enhances absorption of the plant iron — the so-called "meat factor."
- Fermented foods: Fermentation reduces phytate content, which inhibits iron absorption. Sourdough bread is better for iron absorption than regular bread.
Inhibitors of Iron Absorption:
- Tannins: Found in tea, coffee, red wine and some herbal teas. Avoid these within 1 hour of iron-rich meals or iron supplements.
- Calcium: Competes with iron for absorption. Avoid dairy or calcium supplements at the same time as iron.
- Phytates: Found in wholegrains and legumes. Soaking and cooking reduce phytate content.
- Polyphenols: In some vegetables and whole grains
Choosing an Iron Supplement
Iron supplements come in several forms:
- Ferrous sulphate — most commonly prescribed by GPs; high elemental iron content but can cause constipation and nausea in some people
- Ferrous fumarate — similar efficacy to sulphate; may be slightly better tolerated
- Ferrous gluconate — lower elemental iron content, but generally better tolerated
- Iron bisglycinate (ferrous bisglycinate) — the gentlest form; well absorbed and least likely to cause digestive upset. Popular in health shops and often the best choice for those who have had problems with pharmaceutical iron supplements. Examples include Floradix and similar liquid iron preparations.
- Liquid iron supplements (e.g., Floradix, Spatone) — popular for being gentle on the digestive system; Spatone is natural iron-rich water from a Welsh spa spring
Always confirm iron deficiency with a blood test before supplementing. Iron overload is possible and can be harmful — unlike most vitamins, the body cannot easily excrete excess iron.