Getting outdoors may make you happy but poor mental health shouldn't be blamed on low vitamin D levels or sun exposure, suggests new Australian research.
An observational study by the Royal Women's Hospital, Royal Melbourne Hospital and University of Melbourne has found no association between depressive symptoms, anxiety symptoms or psychological distress with vitamin D status.
Researchers investigated links between mental health and vitamin D among 353 women aged 16 - 25 living in Victoria.
The sun is the greatest source of vitamin D and some studies have previously suggested that people with higher levels of the essential vitamin enjoy better mental health.
The Safe-D study has "unexpectedly" ruled this association out for the general population, said chief investigator Professor John Wark.
It could not rule out the possibility of a link with severe vitamin D deficiency and a number of health outcomes, noted Prof Wark.
Participants completed a series of online questionnaires used by mental health researchers and wore a UV dosimeter to measure personal sun exposure. They also underwent a comprehensive health assessment of their medical history.
A total of 90 women, 26 per cent, reported a previous diagnosis of a mental disorder. The main diagnosis was depression, followed by anxiety.
A quarter, 25 per cent, were found to be vitamin D deficient, 2.5 per cent were severely deficient. Vitamin D levels below 100 nanomoles (nmol/l) is considered deficient.
"There was no association between vitamin D status and the presence of a previous diagnosis of any mental health disorder, nor specifically of depression or anxiety. Likewise, there was no association found between vitamin D status and severity of symptoms," the authors of the research paper wrote.
Better mental health was found among participants with vitamin D serum levels above the recommended level of 125 nmol/L, however only 10 participants had levels above this figure.
Prof Wark says up until now most of the published evidence supporting an association has been confounding.
"We know that people who are depressed are less likely to be physically active and spend less time outdoors so that is linked with lower vitamin D levels because people aren't out in the sunshine. There's actually another factor that explains the apparent association," he told AAP.
"Not for a moment" do the researchers suggest, however, to forget about vitamin D for those with severe deficiency.
"But in the great majority of young women in our community it really is not a health issue based on our studies," Prof Wark said.
