Kids • Nutrition • Brain Health
Vitamin D and Children’s Behaviour: What the Research Says About ADHD
Vitamin D isn’t just for bones — growing evidence suggests it may influence attention, mood, and behaviour during childhood.
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).
Quick takeaway: Several large studies and meta-analyses find an association between lower vitamin D levels and higher ADHD symptoms. This doesn’t prove cause-and-effect — but it does suggest vitamin D may be a modifiable risk factor.
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.
| Study type | What it found | Why it matters |
|---|---|---|
| Prospective cohort | Low vitamin D in childhood linked to higher behaviour symptom scores later (Tuckute et al., 2020) | Stronger design than cross-sectional studies (looks forward in time) |
| Meta-analyses | Children with ADHD tend to have lower vitamin D; deficiency linked to higher odds (Gan et al., 2019; Wang et al., 2018) | Combines multiple studies to estimate overall association |
| Neonatal cohort | Low vitamin D at birth associated with increased ADHD risk later (Sourander et al., 2019) | Suggests early life exposure may be important |
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
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