Impact of Vitamin A Deficiency on Iron Metabolism and Anemia: A Historical Perspective and Research Advances.

This article focuses on the metabolic mechanisms by which vitamin A deficiency (VAD) modulates iron metabolism, leading to vitamin A deficiency anemia (VADA). It reviews evidence that VAD impairs iron mobilization, causing iron to accumulate in storage sites like the liver and spleen, thereby reducing its availability for erythropoiesis despite adequate iron stores. A key factor in this process is the upregulation of hepcidin, a liver-produced hormone that restricts iron absorption and release, which can be triggered both directly by VAD and indirectly via inflammation and systemic infection. The article also discusses how VAD may downregulate erythropoietin production and alter iron regulatory protein 2 (IRP2) expression, further disrupting iron homeostasis and red blood cell production. Understanding these interactions is important for developing effective anemia interventions, especially in low- and middle-income countries where VAD, iron deficiency, and infections commonly coexist.