A new study suggests that iron deficiency may hinder the immune system’s ability to respond to respiratory viruses, including influenza. The research, published in The Journal of Immunology, found that mice fed a low-iron diet had lung immune cells that struggled to produce interferon-gamma, a signaling protein that helps the body fight viral infections.
The work centers on memory T cells, which stay in tissues like the lungs and act quickly if the body encounters the same virus again. According to lead author Dr. Thomas J. Connors of Columbia University, the team wanted to understand how dietary iron shapes these cells during and after infection.
“We hope this study deepens the understanding of how iron influences immune system development and raises awareness of iron deficiency as an important global health issue,” he said.
In the experiment, mice were fed either an iron-rich or iron-deficient diet before being infected with influenza. Both groups formed memory T cells, but the iron-deficient mice showed a notable functional problem. Their lung T cells could not make interferon-gamma at normal levels, even when exposed to iron-rich conditions later on. The impairment appeared to persist beyond the period of deficiency.
The effect was specific to lung tissue, which the researchers say may help explain why iron deficiency is linked to higher risk of respiratory infections and has been associated with conditions such as asthma. Iron deficiency is also one of the most common nutrient deficiencies worldwide, particularly among women and young children.
Because iron deficiency is common, experts say it’s helpful to know where iron comes from in everyday foods. Iron-rich options include beans, lentils, tofu, soy foods, fortified cereals, pumpkin seeds, spinach, beef, poultry and seafood such as canned sardines or salmon. Pairing plant-based iron with vitamin C, like adding bell peppers to beans or having citrus with a meal, can also help the body absorb more.
While the findings cannot be generalized to humans, they highlight a potential mechanism worth studying further. The team plans to work with a pediatric clinic to examine immune responses in children with iron deficiency and determine whether similar patterns appear outside the lab.
Connors noted that the goal is not to suggest iron supplements for everyone, but to explore how maintaining healthy iron levels could support immune function during infection. The authors emphasize that more work is needed to understand how these results translate to people.
This study was supported by grants from the National Institutes of Health and Columbia University through the Clinical and Translational Science Awards Program, along with support from the Columbia Flow Cytometry Core and NewYork-Presbyterian Hospital.