Study reveals dietary iron deficiency impairs lung immune cells' viral defense - Video

Early iron deficiency during childhood doesn't merely cause temporary weakness-it can create lasting scars on the lungs' immune defenses, making kids more vulnerable to viruses like flu even years later. Researchers at Columbia University uncovered this by examining memory T cells, the immune system's "memory keepers" that rally against repeat infections.

Their detailed findings, published in the Journal of Immunology, explain why iron-poor children face heightened risks of severe illness and chronic respiratory issues.

Iron deficiency, the world's most common nutritional shortfall affecting nearly 10% of U.S. children and disproportionately young ones globally, strikes during critical immune maturation phases.

Without sufficient iron, lung-resident immune cells fail to produce essential proteins like interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α). These signaling molecules alert and activate defenses to destroy viruses, but low iron disrupts their production, impairing both immediate responses and long-term memory.

To pinpoint iron's isolated role, the team fed mice iron-rich or iron-poor diets, then challenged them with influenza virus. Iron-deficient mice developed severe symptoms, with sluggish T cell activation in the lungs compared to well-nourished peers. Surprisingly, even severely iron-starved mice formed apparently normal-looking memory T cells.

However, rigorous functional tests revealed these cells produced far less IFN-γ and TNF-α upon re-exposure to the virus-a critical defect persisting even after iron levels normalized. This "immunological memory impairment" was lung-specific, highlighting how early shortages reprogram local defenses irreversibly.

Nearly a decade of human data links iron deficiency to worse flu outcomes, asthma, and recurrent infections. Routine anemia screening detects late-stage harm, but prevention demands proactive steps: iron-rich foods (red meats, beans, fortified cereals, spinach paired with vitamin C for absorption), balanced diets, and regular pediatric checks during growth spurts when immune systems solidify.

Looking ahead, Columbia plans human studies on iron-deficient kids' lung immunity and tissue effects to combat chronic conditions. Prioritizing early iron sufficiency builds lifelong viral shields, underscoring nutrition's profound role in child health.

REFERENCE: Bradley, M. C., et al. (2025). Dietary iron deficiency impairs effector function of memory T cells following influenza infection. The Journal of Immunology. doi: 10.1093/jimmun/vkaf291. https://academic.oup.com/jimmunol/advance-article/doi/10.1093/jimmun/vkaf291/8305832