The link between iron and severe headache has been found in women and not in men. In NHANES data covering 7,880 adults, that held for both iron intake and ferritin, split by age and sex (PMID 34295917). A case-control study found the same pattern: significant differences in women, none in men (PMID 31649807).
That difference is not a coincidence. It runs through menstruation.
What keeps striking me here: women with recurring headache are often told their blood was fine. In many cases only the Hb was looked at. That is the value that falls last.
How does iron deficiency lead to headache?
Iron is needed to carry oxygen and plays a part in producing signalling substances in your brain. Once the store empties, fatigue, concentration problems and headache can follow, often long before there is any anaemia.
That word "store" is the key here.
Your body keeps iron in reserve. Every loss draws on that reserve first, and only once it is gone does your haemoglobin fall. Months to years can pass between your store running down and your Hb responding.
In that in between period you can have symptoms while your blood count still reassures. That is exactly where most women get stuck.
Take two women with the same Hb of 8.0 mmol/l. In one the ferritin is 60, in the other 9. On paper both are "not anaemic". Yet the second is running on a nearly empty store, and you only see that if you look past the Hb.
Why is a normal Hb not enough?
Because Hb and ferritin measure different things. Hb shows how much oxygen carrying protein is in your blood right now. Ferritin shows how much iron you still hold in store. A normal Hb does not rule out a low ferritin, and that is the whole reason this question so often stays unresolved.
| Haemoglobin (Hb) | Ferritin | |
|---|---|---|
| What it measures | Oxygen carrying protein in your blood right now | How much iron you hold in store |
| When it falls | Only once the store has been empty for a while | First, often months to years earlier |
| What a normal result means | No anaemia at this moment | Store adequate at this moment |
| What it does not rule out | An empty iron store | Other causes of your symptoms |
One catch: ferritin also rises with inflammation. If something inflammatory is going on at the same time, a ferritin can look falsely reassuring. That is why it is often read alongside other iron values.
The full explanation of that value is in ferritin levels, and the situation without anaemia in iron deficiency without anaemia.
What does your period have to do with it?
Every period costs iron. With average blood loss your food tops that up again over the month. With heavy blood loss it does not, and your store drops a little further month after month. It happens so gradually that you do not experience it as a change.
You get used to being tired. That is the awkward part.
With menstrual migraine something else joins in that rarely gets named: the same week that triggers the attack also costs you the most iron. Two mechanisms landing in the same days, and easily mistaken for one another.
How to tell whether your blood loss really is heavy is in heavy periods. The consequences for your blood count are in anaemia from heavy periods.
Which values answer this?
Ferritin is the value that moves first, which makes it the most informative for this question. Alongside it, the Hb, serum iron and transferrin saturation are often read, because together they show whether this is a store problem or something else.
A single value on its own is harder to interpret than a set.
An iron status test looks at that combination. If your question is mainly whether there is anaemia, the anaemia panel fits better. Discuss the result with your GP: what a value means for you depends on your symptoms, your blood loss and your history.
The Dutch nutrition centre describes which foods supply iron and why plant based iron is absorbed less readily than iron from animal products. Useful background, but it does not replace a conversation about a low result.
When is it your headache and when is it your iron?
Often a bit of both, and that is a more honest answer than a choice. Iron deficiency does not cause migraine, but it can contribute to headache and to the fatigue around it. If your iron store is low, that is worth investigating in its own right.
There is no blood test that shows migraine. You can let go of that expectation straight away.
Practically: if your headache sits tight around your period, the cycle story leads and you want menstrual migraine. If your headache is instead more frequent and increasingly vague, with tiredness, breathlessness on the stairs or cold hands alongside it, the iron side is the first thing I would have looked at.
The full explanation of hormones and headache is in hormonal headache.
References
- Meng SH, Zhou HB, Li X, et al. Association between dietary iron intake and serum ferritin and severe headache or migraine. Front Nutr. 2021;8:685564. PMID 34295917.
- Tayyebi A, Poursadeghfard M, Nazeri M, Pousadeghfard T. Is there any correlation between migraine attacks and iron deficiency anemia? A case-control study. Int J Hematol Oncol Stem Cell Res. 2019;13(3):164-171. PMID 31649807.
- Reddy N, Desai MN, Schoenbrunner A, Schneeberger S, Janis JE. The complex relationship between estrogen and migraines: a scoping review. Syst Rev. 2021;10(1):72. PMID 33691790.
- Voedingscentrum. Iron. Available via voedingscentrum.nl.
- Thuisarts. Anaemia from iron deficiency. Available via thuisarts.nl.
- RIVM and VZinfo. Migraine: figures and context. Available via vzinfo.nl.
Every blood test result at Lunara includes a professional assessment by a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
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