Iron: What It Does and Where to Find It

Women require more iron than men due to monthly blood loss during menstruation. The NHS recommends 14.8 mg of iron per day for women aged 19-50, compared to 8.7 mg for men. Pregnancy increases the requirement further, as blood volume expands by up to 50% to support the growing baby.

Iron deficiency often develops gradually, making it easy to dismiss early symptoms as just being tired. Watch for these signs:

If you think you may be low in iron, speak to your GP for a blood test.

Not all iron supplements are equal. Common forms include:

• Ferrous sulphate: Most commonly prescribed, affordable but can cause digestive side effects.
• Ferrous fumarate: Better tolerated by some people, good absorption.
• Iron bisglycinate: iron bound to the amino acid glycine.

Take iron with vitamin C (a glass of orange juice works well). Avoid taking iron with tea or coffee. Taking iron on an empty stomach improves absorption but may increase stomach discomfort — find the balance that works for you.

• Absorption is less affected by food and other minerals.
• Ferrous fumarate: Contains a higher percentage of elemental iron (33%) and is reasonably well-tolerated. A good mid-range option.
• Ferrous sulphate: The most commonly prescribed form and the cheapest. However, it has the highest rate of gastrointestinal side effects including constipation, nausea, and dark stools.
• Look for added vitamin C: vitamin C increases iron absorption. A supplement that includes it saves you having to coordinate timing with orange juice.

Iron supplementation may be particularly important for:

• Pregnant women, especially in the second and third trimesters when blood volume increases dramatically
• Vegetarians and vegans — plant-based (non-haem) iron is absorbed at only 2–20% compared to 15–35% for animal-based (haem) iron

Always confirm deficiency with a blood test before supplementing. Excess iron is stored in the body and can cause harm at high levels.

Take your iron supplement with vitamin C-rich foods or drinks (orange juice, strawberries, bell peppers) to dramatically boost absorption. Avoid taking iron within 2 hours of calcium supplements, dairy products, tea, or coffee — all of which inhibit iron absorption. Take it as directed on the label. Cook in cast-iron pans to add small amounts of dietary iron to your food. Pair plant-based iron sources (lentils, spinach, beans) with vitamin C at the same meal.