As parents, we’re always looking for ways to support our children’s brain development — from sleep and nutrition to mental wellbeing. But one nutrient often overlooked is vitamin D, and a growing body of research suggests it may play a role in children’s behaviour and risk of ADHD (attention-deficit/hyperactivity disorder).

Why Vitamin D Matters for the Brain

Vitamin D is traditionally known for supporting bone health, but its role in brain development is increasingly recognised. It affects regions of the brain involved in attention, mood regulation, and executive function.

Vitamin D is thought to:
- Regulate dopamine, a neurotransmitter important for motivation and focus (Groves et al., 2014)
- Reduce neuroinflammation, which has been linked to ADHD symptoms (Khoshbakht et al., 2018)
- Influence brain cell growth and synaptic plasticity during critical developmental periods (Eyles et al., 2013)

What the Research Says: Low Vitamin D and ADHD

1. A Large Birth Cohort Study (Most Powerful Evidence)

In a prospective study involving over 3,600 children, low serum 25(OH)D at age 6 was associated with significantly higher scores on inattention, hyperactivity, and oppositional behaviours at age 10 (Tuckute et al., 2020). The researchers controlled for socioeconomic status, BMI, physical activity, and sun exposure.

2. Meta-Analyses Support the Association

A meta-analysis by Gan et al. (2019) reviewed data from over 2,000 children and found that those with ADHD had significantly lower levels of vitamin D than healthy controls.
Similarly, Wang et al. (2018) conducted a broader meta-analysis and found that vitamin D deficiency was associated with a 40% increase in the odds of ADHD.

3. Vitamin D at Birth and ADHD Risk

In a Danish cohort study, low neonatal vitamin D levels were associated with a 34% increased risk of ADHD by adolescence (Sourander et al., 2019). This suggests that maternal vitamin D status during pregnancy may play a critical role in neurodevelopment.

Biological Mechanisms: How Vitamin D Influences the Brain

Vitamin D receptors are expressed in the prefrontal cortex, hippocampus, and dopaminergic neurons, all areas implicated in ADHD.
Experimental studies have shown that vitamin D affects the development of dopaminergic pathways, modulates immune responses in the brain, and regulates neurotrophins such as BDNF (Eyles et al., 2013).

What Can Parents Do?

Vitamin D deficiency is common among children in the UK, especially during the winter months.
According to NHS guidance, all children over 1 year should receive 10 micrograms (400 IU) of vitamin D daily, particularly between October and March (NHS, 2023).

To support healthy levels:

• Offer a balanced diet with plenty of veggies
• Encourage daily outdoor play
• Offer a supplement with at least 10 micrograms (400 IU) per serving

Always check with a GP or health visitor if you are unsure.

The current evidence suggests that vitamin D deficiency may be a modifiable risk factor for ADHD, especially when it occurs during early childhood or pregnancy. While more clinical trials are needed, ensuring adequate vitamin D intake is a simple step parents can take to support cognitive and behavioural development. Following NHS guidance and supplementing your children over the age of 1 is a good start!

References

• Eyles, D.W., Burne, T.H. and McGrath, J.J. (2013) ‘Vitamin D, effects on brain development, adult brain function and the links between low levels of vitamin D and neuropsychiatric disease’, Frontiers in Neuroendocrinology, 34(1), pp. 47–64.
• Gan, J., Galer, B.S., Ma, D. and Wang, R. (2019) ‘Lower serum vitamin D levels in children and adolescents with attention-deficit/hyperactivity disorder (ADHD): a meta-analysis’, Neuroscience Letters, 711, p.134441. PMID: 31195282
• Groves, N.J., McGrath, J.J. and Burne, T.H. (2014) ‘Vitamin D as a neurosteroid affecting the developing and adult brain’, Annual Review of Nutrition, 34, pp.117–141.
• Khoshbakht, Y., Heshmat, R., Mohammadpour, T., Majdzadeh, R. and Shariati, M. (2018) ‘Vitamin D deficiency and attention deficit hyperactivity disorder: a systematic review and meta-analysis’, Nutritional Neuroscience, 21(6), pp. 397–408.
• NHS (2023) Vitamins for children. Available at: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
• Sourander, A., Sucksdorff, D., Chudal, R., et al. (2019) ‘Neonatal vitamin D status and risk of attention deficit hyperactivity disorder’, Journal of the American Academy of Child & Adolescent Psychiatry, 58(7), pp. 672–678.e2. PMID: 31831868
• Tuckute, G., Viljakainen, H., Saari, A., et al. (2020) ‘Associations of vitamin D levels in childhood with behavioural problems in adolescence’, Psychoneuroendocrinology, 113, p.104554. PMID: 31368773
• Wang, T., Liu, K., Wang, Y., et al. (2018) ‘Association between vitamin D status and attention deficit/hyperactivity disorder: a systematic review and meta-analysis of observational studies’, Nutritional Neuroscience, 21(7), pp. 539–547. PMID: 30049274