Higher vitamin D in pregnancy could mean sharper minds for kids years later. A large US study found early pregnancy may be the key window for boosting brain development, especially in children of Black mothers.
Vitamin D levels during pregnancy are known to affect the health of both mother and fetus. In addition to being crucial for bone health and calcium regulation, maintaining adequate gestational vitamin D levels has also been associated with a reduced risk of preeclampsia, gestational diabetes, low birth weight, and premature birth.
Now, a new study by the Environmental Influences on Child Health Outcomes (ECHO) Cohort, a research program supported by the US National Institutes of Health (NIH), which includes researchers from institutes across the country, has found that higher vitamin D levels during pregnancy were linked to better scores on cognitive tests in children aged seven to 12.
“Our study provides important new evidence that early pregnancy may be a critical period when vitamin D has the greatest potential to support cognitive development,” said lead author Melissa Melough, PhD, a registered dietitian and assistant professor in the Department of Health Behavior and Nutrition Sciences at the University of Delaware. “This highlights a key opportunity for clinicians to enhance screening and support for vitamin D supplementation before and during pregnancy.”
For this long-term observational study involving 912 mothers and their children, the researchers measured 25-hydroxyvitamin D, abbreviated to 25(OH)D, an indicator of vitamin D status, in either prenatal blood or umbilical cord blood. Samples were taken, on average, at week 23 of the pregnancy. When the children were seven to 12 years old, they were given the NIH Toolbox Cognition Battery, which measures fluid cognition (problem-solving and reasoning in new situations), crystallized cognition (knowledge and skills acquired through experience), and overall cognition.
The researchers used statistical models that adjusted for potential confounding factors like maternal age, socioeconomic status, and other health influences. They also looked for differences by self-reported race and whether certain stages of pregnancy were more important for vitamin D’s effect.
The recommended range for 25(OH)D is 20 to 40 nanograms per milliliter (ng/mL). In study participants, the average vitamin D levels during pregnancy were 23.8 ng/mL. About 38% of mothers were found to be vitamin D deficient; that is, they had levels less than 20 ng/mL. Higher vitamin D levels were associated with better cognition. For every 10 ng/mL increase in gestational vitamin D, the offspring’s overall cognition score was about 1.1 points higher, and their fluid cognition score was about 1.2 points higher. No meaningful change was found in crystallized cognition.
A stronger effect was seen in children of Black mothers. Fluid cognition scores were almost three points higher per 10-ng/mL increase in vitamin D among children of Black mothers, compared to less than one point in children of non-Black mothers. It appeared that timing was important. Early pregnancy seemed to be the most critical period for vitamin D’s impact on later cognitive ability. Differences in vitamin D levels between high- and low-scoring children were most noticeable at this stage.
The study’s findings have important real-world implications. Primarily, it highlights the important role that gestational vitamin D plays in brain development and cognitive functioning. Since vitamin D deficiency is common, especially among Black women, who face a higher risk due to skin pigmentation reducing vitamin D synthesis, addressing deficiency before or early in pregnancy could improve childhood cognitive outcomes. From a public policy perspective, routine vitamin D screening and supplementation could be a cost-effective way to support child brain health, especially in high-risk groups.
“Gestational 25(OH)D concentrations were positively associated with cognitive scores, especially in children of Black mothers,” said the researchers. “Given higher deficiency risk among Black women, vitamin D repletion before or in early pregnancy may be an important strategy for reducing racial disparities in child neurodevelopment.”
The study was published in The American Journal of Clinical Nutrition.
Source: ECHO
