Nutritional Status of Children Diagnosed With Autism Spectrum Disorder: A Systematic Review and Meta-Analysis

Autism spectrum disorder (ASD) may impact feeding behaviours, which can affect physical development. We aimed to examine published evidence comparing nutritional status, defined as anthropometry, micronutrient status, and intakes and dietary intake, of children with ASD with those of typically developing children (TDC). Eligibility criteria included any studies that compared nutritional status among children with ASD and TDC. PubMed, Web of Science, Scopus and CENTRAL were searched. We used standardized mean difference (SMD) as an effect size for continuous variables and risk ratio (RR) for dichotomous variables with a 95% confidence interval (CI). Thirty-two studies with 18,480 children (ASD: 2955, TDC: 15,525) were included in our meta-analysis. Children with ASD were statistically significantly shorter than TDC (SMD: -0.16, 95% CI [-0.28, -0.04], I² = 7%), but no difference in weight [-0.12, 95% CI (-0.17, 0.92)] and BMI [-0.06, 95% CI (-0.32, 0.20)]. They had decreased intake of protein [-0.34, 95% CI (-0.52, -0.15)] and nearly all lipid-soluble vitamins: vitamin A (SMD: -0.20, 95% CI [-0.38, -0.02], I² = 37%), vitamin D (SMD: -0.30, 95% CI [-0.53, -0.03], I² = 50%), and vitamin K (SMD: -41, 95% CI [-0.71, -0.10], I² = 0%). Also, children with ASD had a statistically significantly decreased intake of some water-soluble vitamins like folate, riboflavin, thiamine and niacin. Decreased levels of some micronutrients like vitamin D and folate was also found. Children with ASD are statistically significantly shorter than TDC, which can be explained by the lower protein intake and fat- and water-soluble vitamin status and intake. These findings warrant further longitudinal population-based studies.