When researchers exposed overfed mice to UV light, they gained less weight. The mice also displayed fewer warning signs linked to diabetes, such as abnormal glucose levels and resistance to insulin.
Next the researchers applied a cream containing nitric oxide to the overfed mice and found it had the same effect of curbing weight gain as exposure to UV light. Nitric oxide is released by the skin after exposure to sunlight.
Vitamin D, which is produced by the body in response to sunlight and often lauded for its health benefits, does not appear to play a role.
“These observations further indicate that the amounts of nitric oxide released from the skin may have beneficial effects not only on heart and blood vessels but also on the way our body regulates metabolism,” says Martin Feelisch, professor of experimental medicine and integrative biology at the University of Southampton.
Previous studies in people have shown that nitric oxide can lower blood pressure after exposure to UV lamps.
The researchers say the results should be interpreted cautiously, because mice are nocturnal animals covered in fur and not usually exposed to much sunlight. Studies are needed to confirm whether sunshine exposure has the same effect on weight gain and risk of diabetes in people.
“Our findings are important as they 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,” says Shelley Gorman of the Telethon Kids Institute and lead author of the study published in the journal Diabetes.
“We know from epidemiology studies that sun-seekers live longer than those who spend their lives in the shade,” says Richard Weller, senior lecturer in dermatology at University of Edinburgh.
“Studies such as this one are helping us to understand how the sun can be good for us. We need to remember that skin cancer is not the only disease that can kill us and should perhaps balance our advice on sun exposure.”
Source: University of Southampton