Exposure to sunlight can reduce the risk of mental problems among children, suggests study.
According to scientists, kids with low levels of vitamin D are more likely to suffer from depression.
Those with the highest levels of the '"sunshine vitamin" have a 10 per cent lower risk of developing the mental health problem.
The study looked at vitamin D levels in more than 2,700 children when they were aged nine and 13.
Those with the lowest levels of vitamin D were more likely to show signs of depression.
Children with higher levels were also more likely to show a decline in depressive symptoms in their teenage years.
Vitamin D is mainly made by the action of sunlight on the skin, although it can also be found in oily fish, such as tuna.
The study investigated levels of two forms of the vitamin - D2 and D3 - and found the strongest anti-depression link with D3.
Lead researcher Dr Anna-Maija Tolppanen, of Bristol University's school of social and community medicine, said that further research is needed before a change in medical practice could be recommended.
Although vitamin D is found in oily fish, and is routinely added to milk, diet accounts for very little of the nutrient that actually makes it into the bloodstream.