Vitamin D, absorbed mainly from sunlight, reduces the risk of developing asthma, according to research reported in the International Journal of Biometeorology. Spanish scientists have found that children who live in colder and more clouded cities are more likely to develop the disease.
Long exposure to sunlight can cause cancer, but sun avoidance also poses a risk, says study author Alberto Arnedo-Pena, an epidemiologist at the Castellon Public Health Center.
90 percent Vitamin D is synthesized in the skin under the influence of sunlight. In people with asthma, the levels of this vitamin are lower, which can affect the functioning of the respiratory system, the researchers say.
Research conducted among over 45 thousand children and adolescents from nine Spanish cities have found that a greater proportion have asthma in the north of the country, where the sun shines less frequently. This confirms earlier reports of a higher incidence of asthma in less sunlit countries where vitamin D supplements are recommended.
The hypothesis about the effect of the sun vitamin on the risk of asthma first appeared about five years ago, so scientists emphasize that further tests are needed to determine what is the optimal dose of sun (PAP).