Dietary Heme Iron: A Review of Efficacy, Safety and Tolerability

Iron is a fundamental micronutrient essential for oxygen transport, enzymatic activity, and metabolic homeostasis. Yet it remains the most deficient nutrient in the world, with more than 2 billion people estimated with iron deficiency anemia. In the diet, animal foods provide iron primarily as heme iron. Dietary heme iron is absorbed through the active transport pathways catalyzed by heme oxygenase in the intestinal enterocyte. This form of heme differs in its bioavailability, absorption mechanisms, and tolerability compared to non-heme forms of iron, including iron salts and chelates. Adding more heme iron to a diet, including through iron supplements, may help to reduce the prevalence of iron deficiency. Future research should focus on research of heme iron supplementation strategies to enhance absorption efficiency, gut microbiome health, and safety, ensuring optimal iron status across diverse populations.