The blue light emitted by phones, tablets, televisions, and other gadgets may substantially accelerate the process of biological aging in fruit flies (Drosophila melanogaster), new research shows.
Blue light is part of the visible light spectrum, and compared with the rest of that spectrum, it has very short high-energy wavelengths.
There are concerns that the blue light given off over long periods at short distances from electronic screens could meddle with normal cellular processes and disrupt our natural circadian rhythms.
Before we go much further, it's worth remembering that although research done in fruit flies and mice has found signs that blue light may cause cellular damage, it's not yet clear if these findings extend to humans.
Nonetheless, emerging evidence suggests blue light can harm the cells of our skin, but whether that damage is significant or not is still hotly debated. Electronic screens are responsible for just a fraction of the blue light doses we get – sunlight, for instance, is mostly blue light.
In the new study, fruit flies exposed to artificial blue light for 10 or 14 days showed differences in the levels of some small molecules (called metabolites) produced in cells, compared to flies kept in constant darkness.
This, the researchers suggest, could be a sign that cells are aging faster and performing at less than optimal levels.
"We are the first to show that the levels of specific metabolites – chemicals that are essential for cells to function correctly – are altered in fruit flies exposed to blue light," says molecular biologist Jadwiga Giebultowicz from Oregon State University.
Take note, however, that the study only looked at cells outside the eye, such as skin and fat cells, and not retinal cells that sense light.
In the flies, the scientists saw an increase in a metabolite called succinate, which fuels the production and growth of each cell.
There was also a drop in a metabolite called glutamate, one of the molecules responsible for managing the communications between neurons.
While it's worrying that blue light seems to cause these changes, it's important to note that the blue light used on the fruit flies in this study was at a more intense level than what humans are typically exposed to.
The researchers still think, though, that there is some potential for blue light to alter cellular processes along similar lines in people. Other research also shows that bright lights before bed can rob us of good, restful sleep.
"LEDs have become the main illumination in display screens such as phones, desktops, and TVs, as well as ambient lighting, so humans in advanced societies are exposed to blue light through LED lighting during most of their waking hours," says Giebultowicz.
"The signaling chemicals in the cells of flies and humans are the same, so there is potential for negative effects of blue light on humans."
While the new study builds on previous research showing that sustained exposure to blue light can harm the brain and shorten life spans in fruit flies, studies on humans haven't been conclusive so far – especially over longer periods of time.
Humans also haven't been staring at screens for extended periods of time for all that long – the iPhone turned up in 2007, for example – so scientists are still collecting data on the potential damage of lots of screen time, and whether solutions like lenses or glasses can help.
Further research will need to be carried out on people to determine to what extent our cells can cope with blue light exposure.
The research has been published in Frontiers in Aging.