A major new study involving The University of Queensland has found that newborn babies with a vitamin D deficiency are more likely to develop mental health disorders later in life, including attention deficit hyperactivity disorder (ADHD), schizophrenia and autism.
In the largest population study of its kind, researchers examined the vitamin D status of 71,793 individuals, many of whom were diagnosed with a mental health disorder during childhood or early adulthood.
Professor John McGrath from UQ’s Queensland Brain Institute led the study, which was based at the National Centre for Register-Based Research at Aarhus University and the State Serum Institute in Denmark.
Previous research had linked neonatal vitamin D deficiency with schizophrenia and autism, but this study covered a wider range of mental disorders, and included evidence based on two vitamin D-related biomarkers as well as related genetics.
The findings suggest that vitamin D supplementation during pregnancy and early life could help reduce the risk of mental health disorders in adulthood. Vitamin D is vital for a baby’s brain development, and low vitamin D levels are common in pregnant women worldwide.
This is why many countries recommend vitamin D supplements during pregnancy. Just as folate supplements are advised during pregnancy to prevent spina bifida, optimising vitamin D levels early in life may reduce the risk of several neurodevelopmental disorders.
Study details and significance
Researchers analysed vitamin D levels using dried blood spots collected from newborn heel prick tests, which are stored on filter paper, allowing them to test vitamin D status of babies born in Denmark between 1981 and 2005.
They compared vitamin D levels from a random sample of individuals without mental disorders against those diagnosed with autism, schizophrenia, ADHD, major depression, bipolar disorder, and anorexia nervosa. The study found that low vitamin D was associated with increased risk of schizophrenia, autism and ADHD.
It is believed that vitamin D levels in adulthood do not influence these disorders, but rather it is the low vitamin D during early brain development that matters. A newborn cannot produce its own vitamin D; all the vitamin D measured in newborns originates from the mother.
Vitamin D, often called “the sunshine vitamin,” is primarily obtained through sun exposure but is also found in some foods and supplements. In Australia, margarine is fortified with vitamin D by law.
What Does This Mean for Pregnancy and Vitamin D in Europe?
This landmark study reinforces the critical importance of vitamin D sufficiency during pregnancy, not only for skeletal development but now with growing evidence linking it to long-term mental health outcomes in children. For Europe, where vitamin D deficiency is widespread among pregnant women—especially in Northern regions with limited sunlight exposure—these findings carry significant public health implications.
Key takeaways for Europe could include:
- Urgent need for harmonised guidelines: Currently, vitamin D supplementation policies vary widely across European countries. Some recommend routine supplements during pregnancy, while others do not. This new evidence strengthens the case for standardising prenatal care guidelines across the EU, with clear recommendations for vitamin D intake.
- Public health campaigns: Raising awareness among women of childbearing age about the importance of maintaining adequate vitamin D levels—not just for bone health, but potentially to reduce the risk of conditions like ADHD, autism, and schizophrenia in their children—should become a public health priority.
- Potential for prenatal screening updates: Although routine screening for vitamin D deficiency during pregnancy is not yet common practice in most of Europe, this study may prompt re-evaluation of cost-effectiveness and benefit-risk assessments of incorporating such screenings.
- Equity in supplementation access: Ensuring equitable access to affordable vitamin D supplements—particularly in underserved or high-risk communities—may help reduce long-term health disparities in mental health outcomes across populations.
In summary, this study strengthens the case for proactive vitamin D strategies during pregnancy in Europe, similar to how folate supplementation is universally recommended. It offers policymakers, healthcare providers, and expectant parents compelling reasons to view early-life nutrition as a foundation for long-term neurological health.
Read more:
Full study
https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(25)00099-9/abstract
