Moderate exposure to the sun helps prevent obesity and diabetes and is important for good health, an Australian-led study published in the Diabetes journal on Friday revealed.

Ultraviolet (UV) radiation slows weight gain and wards off the symptoms of diabetes, such as abnormal glucose levels and insulin resistance, the study found.

The researchers conducted experiments on mice and found that the benefits of sunlight's UV rays are caused by nitric oxide, which is triggered by sunlight.

Australian researcher Prue Hart, of the Telethon Kids Institute in Perth, said the long-term benefits of exposure to the sun are very strong and melanoma was rare.

She said the mice had been subjected to low dose UV three times a week, suggesting the benefits could be obtained by sensible, moderate sun exposure.

"There is growing obesity because children are being given high- fat diets. Here is a simple way of reducing that pathway to obesity, poor metabolic health and ultimately diabetes," she told the Australian newspaper.

Hart said vitamin D and supplements could not compensate for natural sunlight.

Lead author Shelley Gorman, a Telethon Institute macrobiologist, said the new findings suggest that casual skin exposure to sunlight, together with plenty of exercise and a healthy diet, may help prevent the development of obesity in children.