Dietary Supplement Practices in Children With Inherited Metabolic Disorders Receiving Protein-Restricted Diets

Children with inherited metabolic disorders (IMDs) receiving natural protein-restricted diets may be at risk of micronutrient imbalance. However, data on dietary supplement practices in this population are limited. This study aimed to determine the prevalence of current dietary supplement use and to evaluate supplement types and factors associated with their use.

In this cross-sectional study, 50 children with IMDs receiving natural protein-restricted diets were included. Parents completed a structured 50-item questionnaire during face-to-face interviews. Information on dietary supplement use, reasons for supplementation, and clinical and sociodemographic characteristics was collected.

The prevalence of current dietary supplement use was 36.0% (95% CI, 22.9-50.8). Vitamin-mineral preparations were the most commonly used supplements. Current supplement use was more frequent among children with phenylketonuria who had high dietary adherence than among those with low dietary adherence (50.0% vs. 13.3%, p = 0.034). No significant associations were found with diagnosis, growth status, or sociodemographic characteristics. When dietary supplements were used, they were most often recommended by pediatric metabolic specialists according to individual clinical needs.

Approximately one-third of children with IMDs receiving natural protein-restricted diets were current dietary supplement users. These findings support individualized nutritional assessment and the use of dietary supplements based on clinical evaluation rather than routine supplementation.