Iron Supplements Can Mess with Microbes

Guest BloggerMicrobiome Environment


Iron is the go-to treatment for anemia.

Troubling though is the dysbiosis it can cause. Iron favors strains of pathogenic species over more healthful ones.

In the genital tract, for instance, Gardnerella vaginalis, Trichomonas vaginalis and Candida albicans require iron for adhesion.  Most lactobacilli, which maintain a healthy vaginal ecosystem, do not. And in another example with 115 randomized Kenyan infants, those receiving iron-containing micronutrient powders showed adverse gut microbiome effects: increased pathogens as well as intestinal inflammation.

Global organizations such as the World Health Organization recommend routine iron supplementation despite there being good evidence that elevated iron stores predispose to systemic infection and inflammation.

Iron supplements: impact in a 2019 report

Indeed, the impact of oral iron supplements (OIS) use on the clinical outcomes of patients with gram-negative bacteremia has not been evaluated.

A retrospective study was done recently to explore the impact of OIS on the outcomes of such patients. Alaa Atamna and colleagues from Israel published Chronic use of oral iron supplements is associated with poor clinical outcomes in patients with gram-negative bacteremia in European Journal of Clinical Microbiology & Infectious Diseases

In this study, the cohort was divided into chronic OIS users (study group) and nonusers (control group); it included 232 patients; 44 patients in the study group and 188 in the control one. The urinary tract was the main source of the bacteremia, of which Escherichia coli comprised the majority.

Results of iron supplementation
  • Septic shock at presentation was increased.
  • 30-day mortality was increased.
  • No impact on length of hospital stay was seen.

“There is a significant association between chronic OIS exposure and increased adverse outcomes in patients with gram-negative bacteremia .These findings might have important clinical implications.”

Healthcare providers should look at this oft overlooked link to pathogen growth in their patients.

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