目的 分析婴儿食物过敏（food allergy, FA）起病初期粪便铁代谢相关蛋白的表达特征，探讨肠道局部铁稳态失衡与婴儿FA的关联。 方法 采用基于前瞻性临床队列的巢式病例对照研究设计，纳入2024年10月—2025年6月期间来自门诊、儿童保健部及社区招募的疑似FA婴儿162例，根据标准化口服食物激发试验分为FA组（n=88）和非FA组（n=74），采用酶联免疫吸附试验检测确诊前采集的基线粪便中铁代谢相关蛋白水平，并测定粪便非血红素铁含量，比较两组差异。 结果 FA组起病高峰集中于4~6月龄，与胎儿期生理性铁储存耗竭阶段高度重合。临床表现以消化道症状为主。与非FA组相比，FA组粪便转铁蛋白受体1浓度显著升高（P<0.001），而铁蛋白重链、铁蛋白轻链浓度及非血红素铁含量均显著降低（均P<0.05）。组间乳铁蛋白及膜铁转运蛋白浓度差异均无统计学意义（P>0.05）。 结论 FA婴儿在起病初期即存在肠道局部铁稳态失衡，表现为铁摄取信号增强与铁储备水平下降并存的“功能性缺铁”状态，提示肠道局部铁稳态失衡与婴儿FA的早期发生存在关联。

Objective To investigate the expression patterns of fecal iron metabolism-related proteins at the early stage of food allergy (FA) onset in infants, and to explore the association between imbalance of local intestinal iron homeostasis and infant FA. Methods A nested case-control design within a prospective clinical cohort was used. From October 2024 to June 2025, 162 infants with suspected FA were recruited from outpatient clinics, the child health department, and community settings, and classified into an FA group (n=88) and a non-FA group (n=74) according to standardized oral food challenge results. Baseline fecal samples collected prior to diagnosis were tested by enzyme-linked immunosorbent assay for iron metabolism-related proteins, and fecal non-heme iron content was measured. Group differences were compared. Results FA onset peaked at 4-6 months of age, coinciding with the period of physiological depletion of fetal iron stores. Gastrointestinal symptoms predominated. Compared with the non-FA group, the FA group had significantly higher fecal transferrin receptor 1 concentrations (P<0.001) and significantly lower ferritin heavy chain, ferritin light chain, and non-heme iron content (all P<0.05). No significant between-group differences were observed in lactoferrin or hephaestin concentrations (P>0.05). Conclusions Infants with FA exhibit an imbalance of local intestinal iron homeostasis at the early stage of disease onset, characterized by enhanced iron uptake signaling alongside reduced iron storage, indicative of a functional iron deficiency state. This imbalance appears associated with the early occurrence of infant FA.