Iron supplementation does not worsen respiratory health or alter the sputum microbiome in cystic fibrosis

J Cyst Fibros. 2014 May;13(3):311-8. doi: 10.1016/j.jcf.2013.11.004. Epub 2013 Dec 13.


Background: Iron supplementation for hypoferremic anemia could potentiate bacterial growth in the cystic fibrosis (CF) lung, but clinical trials testing this hypothesis are lacking.

Methods: Twenty-two adults with CF and hypoferremic anemia participated in a randomized, double-blind, placebo-controlled, crossover trial of ferrous sulfate 325mg daily for 6weeks. Iron-related hematologic parameters, anthropometric data, sputum iron, Akron Pulmonary Exacerbation Score (PES), and the sputum microbiome were serially assessed. Fixed-effect models were used to describe how ferrous sulfate affected these variables.

Results: Ferrous sulfate increased serum iron by 22.3% and transferrin saturation (TSAT) by 26.8% from baseline (p<0.05) but did not affect hemoglobin, sputum iron, Akron PES, and the sputum microbiome.

Conclusions: Low-dose ferrous sulfate improved hypoferremia without correcting anemia after 6weeks. We did not observe significant effects on sputum iron, Akron PES, and the sputum microbiome. Although we did not identify untoward health effects of iron supplementation, a larger blinded randomized controlled trial would be needed to fully demonstrate safety.

Keywords: Anemia; Cystic fibrosis; Hepcidin-25; Hypoferremia; Iron; Microbiome.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Anemia, Iron-Deficiency / drug therapy*
  • Anemia, Iron-Deficiency / etiology
  • Anemia, Iron-Deficiency / metabolism
  • Cross-Over Studies
  • Cystic Fibrosis / complications*
  • Cystic Fibrosis / metabolism
  • Double-Blind Method
  • Female
  • Ferrous Compounds / administration & dosage*
  • Ferrous Compounds / adverse effects*
  • Hepcidins / metabolism
  • Humans
  • Male
  • Microbiota / drug effects*
  • Middle Aged
  • Placebos
  • Sputum / drug effects
  • Sputum / microbiology
  • Treatment Outcome
  • Young Adult


  • Ferrous Compounds
  • Hepcidins
  • Placebos
  • hepcidin 25, human
  • ferrous sulfate