A study, published in the journal, Scientific Reports, highlights another powerful benefit of sunlight. Already known for stimulating vitamin D production, sunlight may also have an energizing effect on T cells, a type of white blood cell that activates cells in the body to fight infection.
Researchers at the USA's Georgetown University Medical Center have found that sunlight plays a positive role in the action of T lymphocytes, or T cells, which allow the human body to combat pathogens.
The study found that blue light present in sunlight directly activates the cells, both in samples taken from mice and humans, by increasing their speed of movement. This, in turn, makes them more effective at fighting infection.
The T-cell response was found to be driven by hydrogen peroxide, a compound that white blood cells release when an infection is detected in the body. It serves to kill bacteria and to rally T cells to mobilize an immune response.
Given the large surface area of human skin, all of the T cells present in skin could potentially benefit from this phenomenon through exposure to blue light, the researchers suggest.
Note that vitamin D is only produced in the body via exposure to UV rays, which can be harmful in cases of prolonged sun exposure.
If blue light from the sun's rays is capable of energizing infection-fighting T cells, it could be a potential means of treatment for boosting immunity in many patients, the researchers conclude.