Prolonged exposure to blue light, such
as that which emanates from your phone, computer and household fixtures,
could be affecting your longevity, even if it's not shining in your
eyes.
New research at Oregon State University suggests that the blue
wavelengths produced by light-emitting diodes damage cells in the brain
as well as retinas.
The study, published today in Aging and Mechanisms of Disease,
involved a widely used organism, Drosophila melanogaster, the common
fruit fly, an important model organism because of the cellular and
developmental mechanisms it shares with other animals and humans.
Jaga Giebultowicz, a researcher in the OSU College of Science who
studies biological clocks, led a research collaboration that examined
how flies responded to daily 12-hour exposures to blue LED light --
similar to the prevalent blue wavelength in devices like phones and
tablets -- and found that the light accelerated aging.
Flies subjected to daily cycles of 12 hours in light and 12 hours in
darkness had shorter lives compared to flies kept in total darkness or
those kept in light with the blue wavelengths filtered out. The flies
exposed to blue light showed damage to their retinal cells and brain
neurons and had impaired locomotion -- the flies' ability to climb the
walls of their enclosures, a common behavior, was diminished.
Some of the flies in the experiment were mutants that do not develop
eyes, and even those eyeless flies displayed brain damage and locomotion
impairments, suggesting flies didn't have to see the light to be harmed
by it.
"The fact that the light was accelerating aging in the flies was very
surprising to us at first," said Giebultowicz, a professor of
integrative biology. "We'd measured expression of some genes in old
flies, and found that stress-response, protective genes were expressed
if flies were kept in light. We hypothesized that light was regulating
those genes. Then we started asking, what is it in the light that is
harmful to them, and we looked at the spectrum of light. It was very
clear cut that although light without blue slightly shortened their
lifespan, just blue light alone shortened their lifespan very
dramatically."
Natural light, Giebultowicz notes, is crucial for the body's
circadian rhythm -- the 24-hour cycle of physiological processes such as
brain wave activity, hormone production and cell regeneration that are
important factors in feeding and sleeping patterns.
"But there is evidence suggesting that increased exposure to
artificial light is a risk factor for sleep and circadian disorders,"
she said. "And with the prevalent use of LED lighting and device
displays, humans are subjected to increasing amounts of light in the
blue spectrum since commonly used LEDs emit a high fraction of blue
light. But this technology, LED lighting, even in most developed
countries, has not been used long enough to know its effects across the
human lifespan."
Giebultowicz says that the flies, if given a choice, avoid blue light.
"We're going to test if the same signaling that causes them to escape blue light is involved in longevity," she said.
Eileen Chow, faculty research assistant in Giebultowicz's lab and
co-first author of the study, notes that advances in technology and
medicine could work together to address the damaging effects of light if
this research eventually proves applicable to humans.
"Human lifespan has increased dramatically over the past century as
we've found ways to treat diseases, and at the same time we have been
spending more and more time with artificial light," she said. "As
science looks for ways to help people be healthier as they live longer,
designing a healthier spectrum of light might be a possibility, not just
in terms of sleeping better but in terms of overall health."
In the meantime, there are a few things people can do to help
themselves that don't involve sitting for hours in darkness, the
researchers say. Eyeglasses with amber lenses will filter out the blue
light and protect your retinas. And phones, laptops and other devices
can be set to block blue emissions.
"In the future, there may be phones that auto-adjust their display
based on the length of usage the phone perceives," said lead author
Trevor Nash, a 2019 OSU Honors College graduate who was a first-year
undergraduate when the research began. "That kind of phone might be
difficult to make, but it would probably have a big impact on health."
Oregon State University
Story Source:
Materials provided by Oregon State University. Original written by Steve Lundeberg. Note: Content may be edited for style and length.
Materials provided by Oregon State University. Original written by Steve Lundeberg. Note: Content may be edited for style and length.
Journal Reference:
- Trevor R. Nash, Eileen S. Chow, Alexander D. Law, Samuel D. Fu, Elzbieta Fuszara, Aleksandra Bilska, Piotr Bebas, Doris Kretzschmar & Jadwiga M. Giebultowicz. Daily blue-light exposure shortens lifespan and causes brain neurodegeneration in Drosophila. npj Aging and Mechanisms of Disease, 2019 DOI: 10.1038/s41514-019-0038-6
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