Vitamin D and Brain Development

Context:

A major study published in The Lancet Psychiatry has linked vitamin D levels at birth to the later risk of neurodevelopmental and psychiatric disorders, sparking global interest — especially in countries like India, where deficiency is common despite abundant sunlight.

Key Findings from the Danish Study:

Researchers in Denmark analysed data from 88,764 individuals born between 1981 and 2005, using dried blood samples collected as part of a national newborn screening programme. These samples were tested for:

25-hydroxyvitamin D (25(OH)D): Standard marker for vitamin D levels
Vitamin D-binding protein: Helps transport and prolong the activity of vitamin D in the body

These individuals were tracked for diagnoses of mental health conditions including schizophrenia, ADHD, autism, depression, bipolar disorder, and anorexia.

Major Findings:

Higher vitamin D levels at birth were linked with:

18% lower risk of schizophrenia
11% lower risk of ADHD
7% lower risk of autism

Modelling projections showed that if all babies had vitamin D levels in the top 60% of the sample:

15% of schizophrenia cases
9% of ADHD cases
5% of autism cases
could potentially be prevented.

No clear link was found between neonatal vitamin D and depression or bipolar disorder, likely due to their later onset in life.

Testing Causality:

To check whether the observed link was causal or coincidental, researchers used two genetic methods:

Polygenic Risk Score (PRS): Individuals genetically predisposed to higher vitamin D levels had lower risk of schizophrenia, ADHD, and autism. This ruled out reverse causation.
Mendelian Randomisation: Showed stronger evidence that vitamin D levels directly affect the risk of these disorders, particularly ADHD. However, some genetic overlap with other traits could not be ruled out.

India’s Vitamin D Challenge:

Despite abundant sunshine, vitamin D deficiency is widespread in India:

In a study from Uttarakhand, 74% of infants and 85.5% of their mothers were vitamin D deficient.
In Bengaluru, 92.1% of newborns were found deficient.
Research shows a direct link between maternal vitamin D levels and newborn levels — indicating intergenerational deficiency.

Key Issues:

During pregnancy, especially in the third trimester, the need for calcium and vitamin D rises sharply.
Sunlight exposure alone is not sufficient unless accompanied by dietary intake or supplementation.
Routine screening for vitamin D is rare, especially in rural and semi-urban areas.

The Way Forward

Early-life nutrition, including vitamin D, plays a key role in neurodevelopment.
Preventive strategies like routine antenatal supplementation (starting in early pregnancy) may help reduce deficiency.
Clinical experience in India shows that high-dose vitamin D supplementation in the third trimester improves maternal and neonatal levels without safety concerns.

Conclusion:

Vitamin D is not just about bones — it may shape the developing brain too. While it is not a cure-all, adequate levels during pregnancy and early life appear to offer some protection against conditions like ADHD, schizophrenia, and autism. In the Indian context, early screening and supplementation could become a vital public health tool in safeguarding both physical and mental health in future generations.