Does vitamin D improve memory or attention?

Observational studies link higher vitamin D with better attention and faster processing speed, especially in older men. This shows association—not proof of causation.

Can vitamin D help with mood?

Low vitamin D has been associated with worse mood in older adults. Some people report mood benefits when correcting deficiency, but results vary.

What about Alzheimer’s disease?

Lower vitamin D is associated with poorer cognitive performance in some studies, but it is not yet proven that vitamin D slows or prevents Alzheimer’s.

Should pregnant people take vitamin D for the baby’s brain?

Vitamin D is important in pregnancy, but claims about preventing autism or developmental disorders are still unproven. More research in humans is needed.

Vitamin D and Brain Function

Can Vitamin D Help with Brain Function?

Research published in the Journal of Neurology, Neurosurgery, and Psychiatry (May 21, 2009) examined the relationship between vitamin D levels and cognitive performance in men. The subjects of the study were 3,369 men participating in the Male Aging Study. Men with higher vitamin D levels performed better than those with lower levels on tests measuring attention and speed of information processing. Higher vitamin D status was associated with improved psychomotor speed and visual scanning ability, with the association being most pronounced in older participants.

Additional research appearing in the American Journal of Geriatric Psychiatry (2006; 14(12):1032–1040) compared cognition and mood in 40 individuals with mild Alzheimer’s disease and 40 age-matched subjects without dementia. Lower serum vitamin D levels were associated with poorer cognitive performance, as measured by the Short Blessed Test, as well as poorer mood.

According to an article by Dr. John Cannell published in Medical Hypotheses (e-published October 4, 2007), vitamin D deficiency may also be linked to autism. Dr. Cannell reviewed animal research suggesting that vitamin D deficiency during pregnancy adversely affects proteins involved in fetal brain development. In vitamin D–deficient animal models, offspring were born with increased brain size and enlarged ventricles—abnormalities similar to those observed in some children with autism.

Dr. Cannell also noted that children with rickets often exhibit features associated with autism and that some of these markers have been reported to improve with high-dose vitamin D supplementation. These observations are hypothesis-generating and highlight the need for further research into the role of vitamin D in brain development and neurological function.