A spot of sunshine is always a welcome change from the long gloomy winter months. We crave sunshine not only to warm us, but it also lifts our mood. Sunshine also has many health benefits – one of them is the production of Vitamin D, necessary for strong bones, muscles and overall health. Sunlight is also attributed to reduced incidences of autoimmune diseases and cancers but the process by which sunlight affects this immune mechanism has been unclear until now.
Researchers at Georgetown University Medical Center, Washington DC, have found that sunlight affects T lymphocytes (T cells) present in the skin. T cells play an active role in immune surveillance and boosting our immunity.
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While Vitamin D production requires UV light from the sun which also causes harmful skin cancers, researchers found that T cells are activated by low levels of blue light which is safer and found in sun rays and in special lamps.
The skin is the largest organ in the human body and Home to many microbes. With this report, scientists are able to decode how the skin stays vigilant to any threats from microbes.
T cells basically move to the site of infection to perform an immune response, immediately protecting the body from any threat.
Researchers studied T cells isolated from mice cell culture and human blood, to understand the response of T cells to light. The human skin contains approximately double the amount of T cells present in human blood. Blue light has the capacity to reach the dermis which the second layer of the skin.
The study reports that T cells are intrinsically photoreceptive and they sense and respond to low levels of blue light. Sunlight activates the T cells by producing hydrogen peroxide which triggers a molecular pathway along which the T cells move.
Hydrogen peroxide is a compound which white blood cells produce when they sense an infection or bacteria in order to kill them. This triggers a call to the T cells to move to the site of infection and counter any damage.
When sunlight activates T cells and with the ensuing synthesis of hydrogen peroxide, there is an increase in the movement of T cells, which speeds up the process of their immune response.
The researchers concluded that if blue light triggers only beneficial responses, then it might be helpful to provide blue light therapy to patients to enhance their immunity.
While it was previously thought that the synthesis of Vitamin D is one of the possibilities that has an impact on immunity, with this research, scientists are able to attribute the immune process to the synthesis of T cells because of sunlight.
When you go outside to get your dose of sunshine, know that you are not only producing Vitamin D which is an important element for your health, but you are also building a strong immune system by activating and empowering important cells in your skin.
Source: Scientific Reports
