The link between depression and vitamin D (which we get from exposure to sunlight and from certain foods, like oily fish and fortified breakfast cereals) has already been established in adults but this is the first study to look at the vitamin’s effect in children.
The study, which looked at vitamin D levels in over 2,700 children in the Children of the 90s study when they were 9 years and 8 months old, found that those with higher levels of vitamin D were 10 per cent less likely to show signs of depression when they were tested again at the age of 13 years and 8 months old. Those with higher levels were also more likely to show a decline in depressive symptoms between the ages of 10 and a half and 13 years and 8 months.
Vitamin D supplements are available in two different forms (D3 and D2) but it was not known until now whether both forms were associated with depression. This research shows that the connection between vitamin D and depression is linked to the D3 form, which has important implications for future randomised controlled trials investigating whether vitamin D supplements can prevent depression or improve mood in depressed people.
The authors stress that without evidence from randomised controlled trials, the findings do not warrant changes in nutritional policy nor do they recommend that routine testing for vitamin D should be introduced (in general or for children with a family history of depression) or that children should be routinely supplemented with high doses of vitamin D to prevent depressive symptoms. They also emphasise that although certain studies show that high levels of vitamin D are associated with numerous other health benefits, including better respiratory health, lower risk of several types of cancer, asthma and cognitive decline, that these studies have often provided mixed and inconclusive results.
Speaking about the findings, lead author Dr Anna-Maija Tolppanen, said: “Given the importance of depression in childhood and adolescence and the relative ease with which vitamin D levels could be increased with supplements, randomised controlled trials to assess its effectiveness in preventing depressive symptoms would be appropriate.”
‘The association of serum 25-hydroxyvitamin D3 and D2 with depressive symptoms in childhood – a prospective cohort study’ by Anna-Maija Tolppanen, Adrian Sayers, William D. Fraser, Glyn Lewis, Stanley Zammit and Debbie A. Lawlor in the Journal of Child Psychology and Psychiatry, Volume 53, Issue 1, January 2012. DOI : 10.1111/j.1469-7610.2011.02518.x