A study conducted by the Harvard Medical School has found that high vitamin D intake during pregnancy can reduce a child's risk of developing asthma, while also improving their lung function.
The trial, which was published in Biomedicine & Pharmacotherapy, found that mothers who have high levels of vitamin D in their blood tend to have children with better respiratory health than those with low levels.
This suggests that vitamin D is a crucial nutrient involved in prenatal respiratory development, and that sufficient intake of the nutrient is important for the long-term health of a child.
Establishing a pharmacokinetic model
The role of vitamin D in supporting overall health has long been understood, though research has increasingly highlighted the necessity of the nutrient in pregnancy.
Currently, the World Health Organization (WHO) suggests that women should consume adequate levels of vitamin D through either the environment, their diet or via supplementation, as it can reduce the likelihood of "pre-eclampsia, gestational diabetes mellitus, preterm birth and other tissue-specific conditions".
However, the WHO also states that there is currently a lack of evidence to suggest that vitamin D supplementation can improve maternal and infant health.
Therefore, researchers at the Harvard Medical School combined data from two randomised controlled trials (RCTs) assessing the impact of prenatal vitamin D exposure, allowing the team to create a pharmacokinetic model.
They primarily looked into how prenatal vitamin D exposure may affect a child's likelihood of developing asthma or 'wheezing' between the ages of three to six — though they also looked at a child's lung function between the ages of six to eight.
Prenatal vitamin D as a protector against respiratory illness
Notably, from modelling the results of these two RCTs, the team at Harvard Medical School found that higher levels of maternal blood vitamin D levels were associated with a reduced risk of asthma and wheezing at both three and six years.
This reduced a child's risk of developing these symptoms by 56 and 41% at ages three and six, respectively.
They also determined that prenatal vitamin D exposure could benefit a child's respiratory health six to eight years after birth, as those with high exposure generally exhibited better lung function than those who experienced low exposure in utero.
It should also be noted that these effects were seen in all groups "when accounting for sociodemographic and socioeconomic factors", suggesting that vitamin D supplementation could be a cost-effective and beneficial intervention for expecting mothers looking to support their child's respiratory development.