Iron supplementation is often associated with gastrointestinal side effects, which may impact treatment adherence. As a result, researchers have explored different dosages and frequencies of supplementation.
One meta-analysis looked at intermittent (once, twice, or three times per week) iron supplementation vs. daily supplementation for improving iron status and preventing anemia in menstruating adolescent and adult women. Both had similar effects on hemoglobin levels and the risk of anemia. However, daily supplementation proved more effective in increasing ferritin levels (although with low quality of evidence), which may be especially significant in populations with a high prevalence of ID, which is characterized by adequate levels of hemoglobin but low ferritin and/or transferrin saturation.[1] Moreover, there were no significant differences in treatment adherence or in the side effects experienced among participants in the two groups.[2] There is currently no evidence that intermittent supplementation offers advantages in terms of fewer side effects or improved adherence compared to daily supplementation.
In another study, iron-depleted (but not deficient) participants took the same iron dose either daily or on alternate days for 14 and 28 days, respectively. The alternate-day dosing regimen resulted in reduced levels of hepcidin (a hormone responsible for regulating iron homeostasis in the body) and greater iron absorption. However, the impact on iron status remained unclear because there were no notable differences in serum iron, ferritin, or hemoglobin levels between the two groups at the end of the trial. Additionally, the alternate-day dosing group reported experiencing less nausea but more headaches.[3] A subsequent study by the same author, including individuals with ID, confirmed these findings. However, the study’s duration was too short to assess the long-term effects on iron status.[4]
References
- ^Al-Nassem, A. et alIron deficiency without anemia: a diagnosis that mattersClin Med.
- ^Fernández-Gaxiola AC, De-Regil LMIntermittent iron supplementation for reducing anaemia and its associated impairments in adolescent and adult menstruating womenCochrane Database Syst Rev.(2019 Jan 31)
- ^Stoffel NU, Cercamondi CI, Brittenham G, Zeder C, Geurts-Moespot AJ, Swinkels DW, Moretti D, Zimmermann MBIron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trialsLancet Haematol.(2017 Nov)
- ^Stoffel NU, Zeder C, Brittenham GM, Moretti D, Zimmermann MBIron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic womenHaematologica.(2019 Aug 14)