Iron Deficiency Anemia in Infants—Diagnostic Challenge and Assessment of Dietary Impact on Its Prevalence

<b>Background/Objectives</b>: Iron deficiency affects 2% of infants under six months of age and 4-18% of infants aged 6-12 months and may lead to anemia. Given the consequences of iron deficiency in infancy and the importance of adequate nutrition, this study aimed to assess indicators of iron metabolism in infants whose parents participated in nutritional education. <b>Methods</b>: The study included 104 infants, divided into a study group (SG, <i>n</i> = 52) receiving a nutritional education intervention and a control group (CG, <i>n</i> = 52). Peripheral blood morphology parameters and biochemical markers, e.g., iron status (serum iron, transferrin, ferritin, and hepcidin), were evaluated at 3 and 12 months of age. Additionally, at study end, parents completed a three-day dietary diary to assess their infant's iron intake. <b>Results</b>: After nearly one year of intervention, no cases of anemia based on hemoglobin concentration were identified in either group. However, infants in the SG were less likely to present iron and ferritin concentrations below reference ranges compared to the CG. In the CG, low ferritin levels occurred more frequently at 12 months than at baseline. This finding may be related to higher dietary iron intake in the SG, as insufficient iron intake was more common among the CG. Heatmap analysis revealed strong positive correlations among erythrocyte indices, confirming their internal consistency. No single parameter emerged as a superior marker of iron deficiency, emphasizing the need for a combined assessment of iron status. <b>Conclusions</b>: Parental nutritional education may improve iron status and reduce the risk of iron metabolism disorders in infants.