The Increasing Prevalence of Autism Spectrum Disorder in the U.S. and Its Implications for Pediatric Micronutrient Status: A Narrative Review of Case Reports and Series

INTRODUCTION: Micronutrient deficiencies are considered uncommon in the United States. However, children with autism spectrum disorder (ASD) are at higher risk due to food selectivity and restrictive eating patterns. The prevalence of ASD in the U.S. has quadrupled over the past two decades, amplifying the need to address nutritional gaps in this population. OBJECTIVE: This narrative review examines the prevalence and clinical impact of underreported micronutrient deficiencies beyond vitamin C in children with ASD using case reports and series. METHODS: Case reports and case series reporting micronutrient deficiencies in children with ASD published from 2014 to 2025 were identified through PubMed and ScienceDirect using search terms "autism and deficiency" and "autism and vitamin A, K, magnesium, iron deficiency". Eligible cases included children aged 2-18 years with ASD and laboratory-confirmed micronutrient deficiencies. RESULTS: A total of 44 cases from 27 articles were analyzed. Frequently reported deficiencies were vitamin D (25.0%), vitamin A (24.8%), B-vitamins (18.0%), calcium (10.8%), and iron (9.6%). Less common deficiencies included iodine, zinc, vitamin E, etc. Diseases such as xerophthalmia, rickets, pellagra, and goiter were reported. Co-occurring deficiencies were present in 70% of cases, and all cases reported food selectivity, with deficiencies occurring despite normal growth parameters in some children. CONCLUSIONS: Based on cases reviewed, children with ASD are at high risk for micronutrient deficiencies, despite meeting normal growth parameters. Further research is needed to develop a standardized nutrition assessment, but combining anthropometric, biochemical, and dietary assessments can aid in early intervention and prevent complications.