SUNLIGHT OFFERS SURPRISE BENEFIT – IT ENERGIZES INFECTION FIGHTING T CELLS

Sunlight allows us to make vitamin D, credited with healthier living, but a surprise research finding could reveal another powerful benefit of getting some sun.

Georgetown University Medical Center researchers have found that sunlight, through a mechanism separate than vitamin D production, energizes T cells that play a central role in human immunity.

Their findings, published today in Scientific Reports, suggest how the skin, the body’s largest organ, stays alert to the many microbes that can nest there.

“We all know sunlight provides vitamin D, which is suggested to have an impact on immunity, among other things. But what we found is a completely separate role of sunlight on immunity,” says the study’s senior investigator, Gerard Ahern, PhD, associate professor in the Georgetown’s Department of Pharmacology and Physiology. “Some of the roles attributed to vitamin D on immunity may be due to this new mechanism.”

They specifically found that low levels of blue light, found in sun rays, makes T cells move faster — marking the first reported human cell responding to sunlight by speeding its pace.

“T cells, whether they are helper or killer, need to move to do their work, which is to get to the site of an infection and orchestrate a response,” Ahern says. “This study shows that sunlight directly activates key immune cells by increasing their movement.”