Low Iron & Still Exhausted? This Other Deficiency May Be Getting In The Way
You start taking iron and expect your energy to come back. But sometimes the fatigue sticks around, even when you're treating an iron deficiency.
In a recent randomized trial1, researchers explored whether vitamin D status could influence how well the body responds to iron treatment.
The results suggest that correcting low vitamin D may do more than address a second deficiency. It could potentially help the body use iron more effectively, too.
About the study
Iron helps make hemoglobin, the protein in red blood cells that carries oxygen throughout the body.
When iron levels are too low, red blood cell production can suffer, contributing to fatigue and other symptoms of anemia.
Researchers followed adults with iron deficiency anemia for 90 days. Participants were divided into three groups.
One had sufficient vitamin D and received iron treatment. The other two were vitamin D deficient. One received iron alone, while the other received iron plus vitamin D. Everyone received an iron-containing supplement along with folate and vitamin B12. Researchers measured hemoglobin, red blood cell counts, ferritin (stored iron), and other blood markers before and after treatment.
The vitamin D group responded better to iron
All three groups improved during the 90-day trial. But the people who received vitamin D alongside their iron treatment had the biggest improvements in several markers of iron and blood health.
Their hemoglobin, red blood cell counts, and ferritin increased more than they did in either of the other groups. So the difference wasn't simply that their vitamin D levels improved.
The group receiving vitamin D also appeared to have a stronger response to the iron treatment itself.
The study doesn't show that vitamin D treats iron deficiency anemia, but it raises the possibility that being deficient in vitamin D could affect how effectively the body uses iron.
Why vitamin D might influence iron
One possible explanation is hepcidin, a hormone that helps control iron absorption and storage.
When hepcidin is high, the body holds onto more iron and absorbs less from food. Vitamin D may lower hepcidin, potentially making more iron available to help produce red blood cells.
This connection is still being studied, and this trial used a specific group and treatment protocol. So the findings don't mean everyone with iron deficiency anemia needs vitamin D.
If iron treatment isn't doing enough
If you're treating iron deficiency anemia but still feel exhausted, don't automatically assume you need more iron. It may be worth asking your healthcare provider whether vitamin D testing makes sense for you.
- Check your levels: A blood test can determine whether you're actually deficient in vitamin D.
- Treat a deficiency appropriately: If your levels are low, your healthcare provider can recommend a vitamin D dose and treatment duration that fits with your iron therapy.
- Keep looking for answers: Persistent fatigue can have several causes, so ongoing symptoms deserve a conversation with your healthcare provider.
The takeaway
Vitamin D may play a role in how well the body responds to iron.
If fatigue lingers despite treatment, it could be worth checking whether you're missing another piece of the puzzle.