The IAEA is inviting research organizations to join its new Coordinated Research Project (CRP) on the potential long term impact of inflammation on iron metabolism. The five-year project will study long term iron absorption and loss from the usual diet in free-living individuals with and without inflammation to better understand iron metabolism during inflammation and its impact on iron requirements in populations with chronic inflammation or recurring infections.
Despite wide implementation of iron supplementation and fortification programmes along with nutrition education and dietary diversification campaigns, anaemia remains a major global public health problem. Although iron deficiency is not the only cause of anaemia globally, it is by far the largest single cause.
Inflammation is part of the immune response to an acute or chronic infection, or other medical insult; it involves a series of unspecific, systemic physiologic reactions to protect the body from damage. This includes protecting the body from iron, which can nourish microorganisms and fuel ongoing oxidative damage. Inflammation could thus affect absorption, utilisation, storage, and mobilisation of iron, and individuals with inflammation might develop iron deficiency and anaemia despite having an adequate dietary iron intake. A stable isotope technique can measure long term whole body iron absorption and loss without being biased by inflammation.
The CRP is expected to generate novel information that will inform the debate on dietary iron requirements for individuals with chronic or recurring inflammation and eventually support the design of interventions to combat iron-deficiency anaemia.
The CRP will be implemented as a multi-centre study involving at least five research teams from low- and middle-income countries. Each team will bring together researchers with experience in conducting cohort and intervention studies as well as dietary assessments. The experience with stable isotope techniques is an asset.
The iron isotope dilution method
The technique builds on the principle of radioisotope studies previously used to determine iron losses. This new method, adapted for stable isotopes and further developed to measure iron absorption, enables direct unbiased measurement of long term iron absorption and loss without any radiation risk. Following dosing with and equilibration of a stable iron isotope (tracer) for approximately 1 year, participants’ iron isotope signature in blood is measured at different time points. The reduction of the tracer concentration as it gets diluted with dietary iron equals iron absorption, and the reduction of the total tracer amount equals iron loss.