INTRODUCTION: Inadequate levels of iron, zinc, and copper have been linked to growth impairment and cognitive and motor development deficits. The objective of this study is to examine the deficiencies of trace elements and their correlation with selective eating patterns and the intelligence quotient (IQ) of children. METHODS AND PATIENTS: The cross-sectional analysis involved 430 children aged between 7 and 10 years. Blood samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to measure the trace elements levels. Children's IQs were assessed using Raven's Standard Progressive Matrices. RESULTS: Among the sample group, 20.3% exhibited iron deficiency, 42.5% had zinc deficiency, and 14% had insufficient copper levels. Single trace element deficiency was observed in 56.9% of the children, while 66.7% showed coexisting deficiencies of iron and zinc. Children with lower development levels exhibited significantly lower serum zinc levels compared to those with higher development levels (76.78 ± 10.67 vs. 81.14 ± 10.19 μg/dL). The analysis reveals that picky eaters had lower serum iron levels (76.59 ± 10.42 μg/dL) and higher serum copper levels (123.74 ± 13.45 μg/dL). CONCLUSION: A strong association was observed between zinc deficiency, picky eating habits, and lower developmental stages. The findings underscore the importance of monitoring nutritional status in children, given the significant implications for their cognitive development.