Attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are some of the most common neurodevelopmental disorders. More recently,  AuDHD, a combination of these conditions, is becoming more prevalent, and nearly half of people with autism also experience ADHD.

Both these conditions have a variety of potential causes, including strong genetic factors. However, genetics aside, research has found that environmental factors play a part in the development of autism and ADHD. One of these proposed factors is prenatal nutrition.

A recent study in Nutrients has found that prenatal vitamin supplementation – particularly with vitamin D, folic acid, and multivitamins – can impact the brain structure of infants as they develop. This means that proper nutrition could help in preventing the development of ADHD and autism in children.

The Link Between Prenatal Nutrition and Neurodevelopmental Disorders

The 2025 “Generation R Study” sheds light on how maternal vitamin supplementation and diet during pregnancy could help to lower the risk of neurodevelopmental disorders in children. The large population-based child development study focused on 3,937 children aged between 9 and 11.

Researchers used the children’s mothers’ folate and vitamin D blood levels and multivitamin use habits to predict neurodevelopmental outcomes in the children. They also assessed the mothers’ overall diet quality and used structural MRI scans to assess the formation of the participants’ brains. The assessment included the brain volume of specific regions associated with traits of ADHD and autism. The children’s parents completed Child Behaviour Checklist and Social Responsiveness Scale questionnaires as well, helping to pinpoint the signs of ASD and ADHD in their children.

The results of the study show a clear connection between mothers’ prenatal nutrition statuses and the risk of ADHD and autism traits in their children. Researchers found that better vitamin D status and diet quality were linked with larger brain volumes in children. They found that this, in turn, was associated with fewer traits of neurodevelopmental conditions.

The study’s authors concluded that while more research is needed, taking vitamin D and other supplements during pregnancy could help reduce the risk that children will experience neurodevelopmental conditions in childhood or later in life.

How Nutrition Status Influences Neurodevelopment

Many other studies have linked maternal vitamin D status with the rate of many brain disorders and conditions. One study from the Royal Society of Chemistry notes that vitamin D has well-known neuroprotective actions in the brain. It confirms that maternal vitamin D deficiency is associated with a number of neurobiological disorders, including depression, developmental defects, autism, and schizophrenia.

According to the paper, proteins and carbohydrates are essential for proper foetal development. Vitamins and minerals are no different, with any deficiencies causing ‘functional changes’ and potential long-lasting health impacts for children.

Research also highlights the importance of nutrient-regulated pathways such as mTOR, which support mitochondrial function and DNA repair. Both systems play critical roles in foetal brain development, and their activity depends heavily on maternal nutrient status. Low levels of micronutrients can disrupt these pathways and may contribute to the altered brain structure seen in conditions such as ADHD and autism.

The role of vitamin D in foetal development is well-studied, too. The vitamin is crucial for proper skeletal development, and it supports healthy brain development by promoting the differentiation of neurons, the formation of the dopamine system, and connections between axons in the brain.

Vitamin D Status and Foetal Brain Development

Aside from being an essential nutrient and a hormone, vitamin D acts as a neuro-steroid. It influences the brain’s development and function by altering gene expression and through other non-genomic activities. The developing brain contains an abundance of vitamin D receptors. These receptors are found in the cortex, hippocampus, thalamus, and hypothalamus.

As a child’s brain develops in the womb, vitamin D aids the process by halting excessive cell growth. It also allows cells to specialise into neurons, supporting apoptosis, enabling cells to die in a structured way as the brain forms and grows.

The Impacts of Maternal and Neonatal Vitamin D Levels

Vitamin D deficiency during pregnancy may cause significant abnormalities in brain development. These lead to structural and chemical changes that can continue into adult life. Additionally, these changes contribute to the development of neurodevelopmental conditions like ASD and ADHD.

A 2021 study published in Molecular Psychiatry echoes these findings. It notes that pregnant mothers with 25OHD (vitamin D3) deficiency at 11 weeks had 1.58 times higher odds of having children with ASD, compared to those with normal D3 levels. Low levels of vitamin D3 in newborns were also linked with 1.33 times higher odds of autism diagnosis later in life.

The study further found that when a pregnant mother and her newborn were both deficient, the odds of an ASD diagnosis were 1.75 times higher. Its findings align with a growing body of evidence that suggests that maternal Vitamin D supplementation supports proper brain development in children. It could also potentially reduce the risk of them developing ADHD, autism, or AuDHD in the future.

In Summary

Studies like the Generation R Study highlight the importance of vitamin D for healthy brain development in children. They also note that vitamin D is vital for increasing the brain volume in regions linked with disorders like ADHD and autism, which may help to reduce the risk of them occurring.

If you are currently pregnant or planning a pregnancy, consider working with a qualified nutritionist to ensure that you get the nutrients required to support your child’s brain development and function. According to the NHS, breastfed babies should be given a vitamin D supplement daily from birth. This intervention can support their brain development, bone health, and overall well-being as they grow.

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