Studies investigating vitamin D status in children and adults appear to find a link between it's deficiency and schizophrenia in newborns and depression in older adults. These findings suggest the importance of taking the vitamin for healthy ageing of the brain as well as physical functioning of the body.
We are all becoming more aware of the role of vitamin D in our health, the NHS recommends vitamin D drops from birth for all breast fed infants and for all adults vitamin D supplementation is advised over the winter months. As we get older, insufficient levels of vitamin D has an impact on frailty status, bone health, cardiovascular disease and mortality and now there is growing interest in the link between vitamin D status and late life mental health.
The senior study author, Dr Eamon Laird, who lead the Trinity College Dublin research team in discovering a 75% increased depression risk in vitamin D deficient patients over a 4 year follow up period said:
"This study shows that vitamin D status is associated with a health condition other than bone health."
"Our previous research has shown that one in eight older adults are deficient in the summer and one in four during the winter. Moreover, only around 8% of older Irish adults report taking a vitamin D supplement."
Newborns deficient in vitamin D had 44% more risk of developing schizophrenia
Professor John McGrath from Aarhus University in Denmark found newborns deficient in vitamin D had 44% more risk of being diagnosed with schizophrenia compared to those with sufficient vitamin D levels. He said:
"As the developing fetus is totally reliant on the mother's vitamin D stores, our findings suggest that ensuring pregnant women have adequate levels of vitamin D may result in the prevention of some schizophrenia cases."
"This is comparable to the role folate supplementation has played in the prevention of spina bifida."
The development of depression could be reduced by having a higher vitamin D status
Dr Laird's study looked at almost 4000 people aged 50 and above over a 4 year period. It looked at the relationship between vitamin D status at baseline and the incidence of depression at 2 and 4 year follow ups.
The findings showed that vitamin D deficiency was linked to a 75% increase in the risk of developing depression by four years. And this was the case even after excluding participants taking anti-depressant medication and vitamin D supplementation.
Professor Rose Anne Kenny of Trinity College Dublin said:
"The new finding that the development of depression could potentially be attenuated by having a higher vitamin D status could have significant policy and practice implications for Government and health services."
"It is our responsibility to now ascertain whether supplementation will influence depression. There are many reasons for vitamin D supplementation in Ireland. Benefits to something as disabling and often silent as depression are therefore important for wellbeing as we age."
Trials of vitamin D supplementation in pregnant women needed to examine the impact on child brain development
Professor McGrath's analysis looked at findings from 2602 individuals to suggest that newborns with a vitamin D deficiency could account for around 8% of schizophrenia cases in Denmark. He said:
"Much of the attention in schizophrenia research has been focused on modifiable factors early in life with the goal of reducing the burden of this disease."
"Previous research identified an increased risk of schizophrenia associated with being born in winter or spring or living in a high-latitude country, such as Denmark."
The hypothesis put forward by Professor McGrath is that low vitamin D levels in pregnant women due to limited sun exposure during winter months might be the cause of this risk and therefore looked at the association between vitamin D deficiency and risk of schizophrenia.
He added: "The next step is to conduct randomised clinical trials of vitamin D supplements in pregnant women who are vitamin D deficient in order to examine the impact on child brain development and risk of neurodevelopmental disorders such as autism and schizphrenia."