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Study links blue light emitted by screens to higher cancer risk

The blue light given off by screens could be hurting more than just our sleep cycles.

Part 2 of this report can be found by clicking here.

NEW ORLEANS -- Children and adults spend 8-to-10 hours a day looking at devices and screens, and the amount of time appears to be growing every year.

Doctors have growing concerns about what all that blue screen light is doing to our health.

A team of researchers at Tulane was the first to discover a connection between cancer, light at night and a very important hormone that is supposed to rise in your body every night when it gets dark.

"This hormone produced by the pineal gland at night, called melatonin, had very potent anti-cancer affects in breast, and a variety of other cancers, including prostate cancer, so melatonin directly acted on cancer cells to slow their growth dramatically," said Dr. David Blask, a Professor of Structural and Cellular Biology and the Associate Director for the Tulane Center for Circadian Biology.

Human breast cancer tumors attached to laboratory rodents an grew when the animals were exposed to light at night. That's because light, especially blue light that comes from screens, keeps your melatonin from rising, but when those animals with human tumors were exposed to human blood with high levels of melatonin, the tumors dramatically shut down.

"So that was really the first proof that melatonin is an anti-circadian, anti-cancer molecule,” Dr. Blask said.

In fact, there’s an 80 percent higher breast cancer risk and three times the prostate cancer risk for night workers exposed to light all night.

So, what about all the artificial city and home lights, and using all those devices, rich in blue light at night?

"So, those are very melatonin suppressant, and we know from studies, from other laboratories, that the blue light from the screens of computers, tablets, cell phones, that's enough light to suppress melatonin and to disrupt the melatonin signal at night," Dr. Blask said.

Medical Watch first reported this nearly a decade ago, but now more discoveries on light and cancer are being uncovered as the research continues.

"Blue light during the day we found, actually amplifies the night time melatonin signals," explained Dr. Blask.

So, blue light in the day is good, because at night it caused a rise in melatonin, seven times the normal amount and for a longer period of time. That's because humans evolved to be exposed to lots of natural blue light, out under the blue skies in the day. With the extra blue light in the day, insulin, glucose and fat levels got better, and so did the cancer protection.

"Those tumors grow really slow, almost as if we had given the animals an oral supplement, or injected them with melatonin," he explained about his research.

Doctors think that one day, exposure to light from special blue LED bulbs in the day, could help chemo work better because without melatonin tumors don't respond to chemo.

In the meantime, there are some things that you can do: Shut off screens a least a half hour or more before bedtime, wear a sleep mask or darken shades to keep your bedroom pitch black, and no night lights for children, even preteens, or during puberty. Use only red nightlights if you have to. White will keep them from the protective effect of melatonin.

"That may make them more susceptible to developing breast cancer (later in life)," Blask said.

Meg Farris can be reached at mfarris@wwltv.com.

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