PD202 - ASSOCIATIONS BETWEEN MATERNAL VITAMIN D STATUS DURING PREGNANCY, AND OFFSPRING GUT MICROBIOME AND METABOLOME

PD202

ASSOCIATIONS BETWEEN MATERNAL VITAMIN D STATUS DURING PREGNANCY, AND OFFSPRING GUT MICROBIOME AND METABOLOME

A. T. Arnadottir^1,2,*, T. Thanh Truong ³, K. F. Corral-Jara², S. Skirnisdottir², S. Knobloch⁴, G. Caporaso⁵, P. Schmitt-Kopplin³, A. M. Klonowski², I. Gunnarsdottir^1,6

¹Food Science and Nutrition, University of Iceland, ²Microbiology, Matis, Reykjavik, Iceland, ³Analytical Biogeochemistry, Helmholtz Munich, Oberschleißheim, ⁴Food Technology, Fulda University of Applied Sciences, Fulda, Germany, ⁵Department of Biological Sciences, Northern Arizona University, Flagstaff, United States, ⁶Unit for Nutrition Research, Landspitali University Hospital, Reykjavik, Iceland

Rationale: Maternal vitamin D status may influence early-life gut microbiome development and metabolic activity, but the relationship is not fully understood.

Methods: Maternal serum 25-hydroxyvitamin D (25(OH)D) was measured at gestational weeks 11–14 (n=171) and offspring fecal samples collected at one (n=135) and two years of age (n=132). Gut microbiota composition was assessed by 16S rRNA gene sequencing (V4 region), and fecal metabolomic profiling was performed by HILIC LC-MS². Associations with metabolomic features, alpha and beta diversity were assessed accounting for confounders such as maternal age and body mass index, delivery mode, breastfeeding, use of antibiotics and children’s intake of sugars and dietary fiber.

Results: Mean±SD maternal serum 25(OH)D concentration was 64±20 nmol/L, with 27% of mothers having levels below 50 nmol/L, 4% below 30 nmol/L and 33% above 75 nmol/L. Most children (93%) received vitamin D supplements at both one and two years. Maternal 25(OH)D was not significantly associated with differences in alpha or beta diversity of the offspring gut microbiota. In contrast, some metabolites showed significant linear associations, and a subset exhibited non-linear, predominantly quadratic relationships. These patterns were observed across multiple metabolic classes, including amino acids and bile acid derivatives (such as indole lactic acid). Multivariate analyses demonstrated a significant quadratic association for metabolomic profiles (R²=0.08 at one year, p=0.024, and R²=0.05 at two years, p=0.040).

Conclusion: Maternal vitamin D status during pregnancy was associated with infant metabolomic profiles but not gut microbiota composition, suggesting a lasting effect on microbial metabolic function in offspring rather than differences in community structure in early life. The observed quadratic associations are consistent with suggested optimal exposure ranges of vitamin D.

Disclosure of Interest: None declared