Low Vitamin D in Pregnancy Linked to Weaker Immunity in Children
- Yul So
- Apr 6
- 1 min read
Apr 6, 2026
Yul So
A research team led by Professor Hong Soo Jong at the National Medical Center, supported by the Korea National Institute of Health, has found that vitamin D deficiency during pregnancy may weaken a child’s immune system and increase the risk of allergies after birth.
The study followed 322 children aged three to nine from a birth cohort focused on respiratory and allergic diseases. Researchers examined their responses to common allergens such as dust mites, pollen, and pet dander. Blood samples were analyzed using combined protein and metabolic profiling to better understand immune activity.
Children who reacted to multiple allergens showed higher levels of inactive vitamin D in their blood. This form of vitamin D cannot be immediately used by the body. These children also had increased levels of immune inflammation and oxidative stress markers, suggesting a disrupted immune balance.
Further analysis revealed that vitamin D levels at birth were closely linked to later immune function. Children with lower vitamin D levels in umbilical cord blood were more likely to show increased inactive vitamin D levels during childhood.
The researchers emphasized that vitamin D status during pregnancy may play an important role in shaping long-term immune health. They recommend that pregnant women maintain adequate vitamin D levels through regular sunlight exposure and supplements. The findings highlight the importance of early nutritional care in reducing the risk of allergic diseases and supporting healthy immune development.
