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How Does Sunlight Boost the Immune System?

Could exposure to sunlight boost the activity of white blood cells? The blue wave lengths help T cells move more quickly to where they are needed.
Hot summer sun vitamin D, source for vitamin D

More than 100 years ago people with tuberculosis were treated in sanatoriums where they were supposed to receive plenty of sunlight. Physicians thought this would help control their infections. Back in the 19th century, of course, scientific understanding of the immune system and its functioning was quite limited.

Does Sunlight Boost Immunity?

There is new evidence, however, that the basic impulse was appropriate. Researchers report that exposure to sunlight appears to activate T cells so they move more rapidly throughout the body.

What Do T Cells Do?

T cells play a crucial role in natural immunity. These white blood cells are crucial for hunting down invading pathogens and attacking them. When they become more mobile they do a better job fighting infections and cancer.

Perhaps this discovery of a sunlight boost to T cell motility explains why people who are exposed to more sunshine are less likely to develop autoimmune diseases and cancer.

Not Just Vitamin D:

While human skin makes vitamin D upon exposure to ultraviolet light, this mechanism is independent of vitamin D. The T cells in skin are extremely sensitive to blue light. This is among the wave lengths contained in sunlight, and it is not the same as ultraviolet light. At low doses, blue light triggers T cells to make hydrogen peroxide. This is what allows them to scoot around more quickly to areas that might need immune system attention.

Scientific Reports, Dec. 20, 2016

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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I have always believed in sun light as medicinal. We are programed for sun light. Please give yourself a chance with a healthy dose of sun light each day. Sunshine is the best!!!

My uncle was born in the early 1900’s with very serious Cerebral Palsy. He was expected to die before he reached a year. My grandparents’ friends suggested they “send him away” to an institution, but my grandmother refused. When my uncle reached 2, it was clear he would never walk or be able to feed himself, and again, the doctors said he would die soon.

My grandmother started sitting in the sun with my uncle for a little while every day, and she continued doing that. My uncle never was able to walk, but he lived to be 56, and even was in charge of a little store that he ran out of my grandmother’s house (with physical help from others). I have no idea if regular exposure to the sun kept my uncle alive, but it certainly didn’t hurt.

Computer screens emit a lot of blue light. So much so, that sleep experts recommend getting away from your computer screen for a while before you go to bed. I have an app on my computer that changes the screen colors slightly according to the time of day, gradually reducing the amount of blues on the screen as it gets later in the evening (f.lux, found at justgetflux.com).

So, perhaps there is actually some benefit to spending long hours staring at my computer screen? Maybe doing it with my shirt off would improve the effect and trigger my T cells to produce hydrogen peroxide and improve my immune system?

Thank you. It’s Winter! I’m wondering if tanning booth UV lights include the kind of blue light to which you refer.

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