Iron: Where Both Deficiency and Excess Do Damage

Iron occupies an unusual position: it is the most common nutritional deficiency in the world and also a nutrient whose excess causes organ damage. Supplementing it without testing is therefore a genuinely bad idea, which does not stop it from being common.

Reading the panel properly

• Ferritin reflects stored iron and is the most useful single number — but it is also an acute-phase reactant, so inflammation raises it and can mask depletion
• Transferrin saturation shows how much of the transport capacity is in use; high values point toward overload
• Haemoglobin falls late. By the time it is low, stores have been empty for some time
• CRP alongside ferritin, so a raised ferritin can be interpreted rather than guessed at

Why the inflammation caveat matters

Someone with chronic inflammation can have a ferritin in the normal range and be functionally iron deficient. Someone else can have a high ferritin purely from inflammation and be told they have iron overload. Neither is resolved without looking at both numbers together.

A ferritin result without a CRP beside it is half a measurement, and it is the half that leads to the wrong conclusion in exactly the people most likely to be tested.

Overload is more common than people think

Hereditary haemochromatosis is among the most common genetic conditions in people of northern European descent. Excess iron accumulates in liver, pancreas and heart and causes damage that is largely preventable if caught. Men and post-menopausal women have no regular route of iron loss, which is why the condition tends to declare itself in middle age.

The historical treatment — regular blood donation — remains effective and free.

If you are genuinely low

• Find the cause before treating the number, particularly in men and post-menopausal women where blood loss needs explaining
• Bisglycinate is better tolerated than sulphate, which causes the constipation that ends most iron courses
• Vitamin C with it improves absorption; tea, coffee, calcium and zinc taken at the same time impair it
• Every other day dosing absorbs better than daily — hepcidin rises after a dose and blocks the next one
• Re-test after three months rather than taking it indefinitely