A recent review published in the journal Nutrients suggests that vitamin D may play a key role in shaping health during the first 1,000 days of life, according to a Mar. 31 article. The review analyzes how maternal, infant, and environmental factors influence nutritional programming from pregnancy through toddlerhood.
This topic is important because the early years are considered both a “window of opportunity” and a “window of susceptibility,” where nutrition can have lasting effects on long-term health. Vitamin D deficiency remains widespread globally, with estimates indicating that about 28% of people are affected.
The review finds that vitamin D is essential for preventing skeletal diseases such as rickets but also points to new evidence suggesting broader roles. Researchers note that vitamin D influences over 1,000 genes through its receptor and may impact immune function, metabolism, and neurodevelopmental processes. However, they say current human clinical evidence for these non-skeletal benefits is still incomplete and varies depending on context.
Meta-analyses involving more than 54,000 pregnant women show that over half had low levels of serum vitamin D. Since infants rely heavily on maternal stores transferred during pregnancy, maternal deficiency could increase risks for adverse outcomes like lower birth weight or small-for-gestational-age infants. For immune regulation, studies involving more than 48,000 participants found a slight reduction in acute respiratory tract infection risk with supplementation—mainly at doses between 400–1,000 IU daily—but no significant effect was seen among infants under one year old.
The review also highlights research linking maternal supplementation to changes in placental gene expression and reduced epigenetic gestational age acceleration; however, it says the clinical significance remains unclear. The authors recommend following guidelines such as those from the Endocrine Society (2024), which suggest empiric supplementation during pregnancy at about 2,500 IU per day while noting that non-skeletal benefits are not yet proven.
Researchers conclude by calling for future studies using precision nutrition approaches to account for genetic differences—such as variations in the vitamin D-binding protein—that might affect individual responses to supplementation.
