An Exploration of Gut Microbiota Mechanisms Underlying Differential Efficacy of Vitamin D Supplementation in Children Associated with Lipid Metabolism

Hui Wang¹Wan-Ying Liu¹Tong-Tong Wang¹Ying-Tan Yu¹Xin-Xu Li¹Fei-Tong Zhang¹Chen-Yang Zhang^2*Xiao Tong^1*

• ¹Jiangnan University Wuxi School of Medicine, Wuxi, China
• ²Jiangnan University, Wuxi, China

Vitamin D plays an indispensable role in children's growth. Although there has been a growing recognition of the importance of vitamin D supplementation, its deficiency remains a prevalent global issue. This deficiency is frequently associated with abnormalities in lipid metabolism, which can impede the normal development of children. In recent years, the gut microbiota, which exerts a significant influence on drug metabolism and nutrient absorption, has captured increasing attention. This study explores gut microbiota mechanisms of differenti al vitamin D supplementation efficacy related to lipid metabolism, offering references for clinical problem - solving. A retrospective analysis of 2,307 pediatric patients found the levels of serum vitamin D and its correlation with lipid metabolism.To explore the potential mechanism,children with vitamin D deficiency underwent a three-month supplementation and one hour of outdoor activities each day.Then, 24 subjects were selected (12 poor and 12 good responders to supplementation). 16S rRNA sequencing analyzed gut microbiota composition to find differential microbiota, and PICRUSt2 was used for functional prediction to identify potential metabolic differences. Our study revealed a widespread prevalence of vitamin D insufficiency or deficiency among children. Moreover, a negative correlation was established between vitamin D levels and lipid metabolism. The results of 16S rRNA sequencing indicated that Agathobacter emerged as the key gut microbiota influencing the efficacy of vitamin D supplementation. Its abundance was found to be negatively correlated with lipid metabolism. Through PICRUSt2 analysis, distinct "other carbohydrate degradation" pathways were identified in children with different outcomes of vitamin D supplementation. This study confirms the widespread occurrence of vitamin D insufficiency or deficiency in children, which is negatively correlated with lipid metabolism. Agathobacter may exert an impact on vitamin D absorption and lipid metabolism through the "other carbohydrate degradation" pathway. Our findings offer more insights for clinical problem - solving and new therapies based on child - gut microbiota interaction.