A GROUNDBREAKING study has provided new evidence that vitamin C in pregnancy may influence childhood lung function by altering DNA methylation at key asthma- and allergy-associated loci, particularly in cases where mothers smoke during pregnancy.
Vitamin C and Lung Function: A Promising Link
In a follow-up to the ‘Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function’ (VCSIP) trial, researchers investigated how prenatal vitamin C supplementation impacted DNA methylation (DNAm) in buccal cells, specifically at loci associated with asthma and allergies. Previous results indicated that babies born to smokers who received vitamin C exhibited improved respiratory outcomes, with benefits persisting through age 5. The current study aimed to deepen understanding by examining the relationship between these improvements and changes in DNAm, focusing on asthma-related genetic markers.
Groundbreaking Findings in DNA Methylation
Using a custom Asthma&Allergy DNA methylation array, researchers profiled over 36,000 CpGs in 137 children, comparing those whose mothers received vitamin C to those who received a placebo. They identified nine genome-wide differentially methylated CpGs (DMCs), with one CpG associated with forced expiratory flow (FEF25-75), a measure of lung function. Importantly, five of these DMCs were linked to the vitamin C treatment effect, with two CpGs annotated to the SLC25A37 gene, which is involved in mitochondrial iron transport, indicating a novel molecular pathway potentially involved in improved lung function.
Vitamin C’s Role in Asthma and Allergy Prevention
This study also found a strong connection between vitamin C supplementation and reduced risk factors for asthma and allergies, especially through the mediation of DNA methylation changes. The identification of these molecular markers opens new avenues for exploring how prenatal interventions can reduce the long-term respiratory risks for children born to smokers. This finding is particularly important given the established link between prenatal smoking exposure and heightened asthma risk in offspring.
Next Steps in Research
The study provides compelling evidence that vitamin C supplementation during pregnancy may have lasting benefits for children’s lung function, potentially through epigenetic modifications. Further research is needed to confirm these findings and explore their broader implications for asthma and allergy prevention in early childhood.
Reference
Shorey-Kendrick LE et al. Vitamin C supplementation to pregnant smokers alters asthma- and allergy-associated CpGs in child buccal DNA at 5 years of age. Clin Epigenetics. 2025;17(1):155.
