Dietary Iron Guide

Haem vs Non-Haem Iron

Two forms of dietary iron with very different absorption: haem iron (from animal products): well absorbed (15-35%). Sources: red meat, poultry, fish, eggs (limited). Non-haem iron (from plant sources): poorly absorbed (2-20%). Sources: legumes, whole grains, dark leafy greens, fortified foods, nuts and seeds. The same 5mg iron: from beef provides ~1mg absorbed iron. From spinach provides ~0.5mg absorbed. Implications: vegetarians and vegans need approximately 1.8× more iron from diet to compensa

Iron Deficiency Anaemia

Most common nutritional deficiency in the UK and worldwide. NHS data: 23% of UK women aged 19-64 have iron deficiency. Up to 50% of pregnant women. 3-7% of UK men. Symptoms: fatigue (most common). Pale skin. Shortness of breath. Cold hands and feet. Brittle nails. Restless legs syndrome. Hair loss. Difficult concentration. Risk groups: menstruating women (especially heavy periods). Pregnant women (target 27mg/day). Vegetarians and vegans. Endurance athletes (mechanical haemolysis, sweat losses).

Maximising Absorption

Iron absorption enhancers (take with iron-rich foods): vitamin C — single most important enhancer. 100mg vitamin C (orange, pepper, kiwi, broccoli) can quadruple non-haem iron absorption. Cook in iron pans (cast iron) — small amount of iron transfers to food. Iron absorption inhibitors (separate from iron meals by 1-2 hours): tea and coffee — tannins bind iron, reduce absorption by 50-90%. Calcium supplements and dairy — compete with iron absorption. Phytates (whole grains, legumes) — bind iron.

Supplementation

When dietary iron is insufficient: ferrous sulphate (200mg = 65mg elemental iron): standard NHS prescription. Effective but causes GI side effects in 20% (constipation, nausea, dark stools). Ferrous fumarate: similar absorption, often better tolerated. Iron bisglycinate (chelated iron): newer form. Better tolerated, fewer GI effects. Less elemental iron per tablet but better absorbed. Liquid iron supplements (Floradix, Spatone): gentler but lower dose — useful for sensitive stomachs but slow to

Not medical advice. This calculator is for general information and education only. Figures are estimates and may not reflect your circumstances. For decisions, consult your GP or a qualified healthcare professional. See our editorial standards.

Iron Intake & Deficiency Risk Calculator

Results update automatically as you type

Enter values above to calculate