A study published in the CMAJ in 2012 included 198 menstruating women who complained of fatigue. They did not have anaemia, but their ferritin, which reflects iron stores, was below 50 μg/L. One group took 80 mg of iron a day for 12 weeks, the other a placebo.
Results
Fatigue fell by 48% in women taking iron and by 29% in those taking placebo. The difference between the groups was 19 percentage points. This suggests that low iron stores can affect how you feel even when a blood test looks “normal”.
What this means for you
- If you feel constantly tired, ask your doctor to check your ferritin, not just your haemoglobin.
- Don’t take iron supplements without tests and your doctor’s advice.
- Heavy periods can increase iron loss, so mention them to your doctor too.
Sources
- Vaucher P., Druais P.-L., Waldvogel S., Favrat B. (2012). Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. CMAJ, 184(11), 1247–1254. doi:10.1503/cmaj.110950